Konstantin Tsiolkovsky

Chapter 1 · 1857 – 1866 The Collodion Balloon

One day, in a house in Ryazan Province, a mother shows her children a toy. It is a tiny balloon made of collodion, a transparent film, inflated with hydrogen. One of the boys is eight or nine. Sixty years later, having become the theorist of spaceflight, Konstantin Tsiolkovsky would place that balloon among the first memories of his life.

Izhevskoye, Ryazan Province

Konstantin Eduardovich Tsiolkovsky was born on September 5, 1857, by the Russian calendar of the time, or September 17 by ours, in the village of Izhevskoye, in the Spassk district of Ryazan Province, southeast of Moscow.

His father, Eduard Ignatyevich, was of Polish origin. He was a forester in state service. His mother, Maria Ivanovna, née Yumasheva, was Russian. The family was large and lived on little.

Tsiolkovsky described his parents in three sentences, in the notes he sent in 1926 to his biographer Nikolai Rynin. “My parents were poor. My father was a failure, an inventor and a philosopher. My mother, as father used to say, possessed the spark of talent.” He adds that on his mother’s side of the family there were some very able people.

Those three sentences are about all he was willing to say of his origins. He warns Rynin, moreover, in the letter that accompanies his notes: they might not meet with his approval, but there is nothing else he can offer, and he should not even ask.

A dream from before books

In 1911, in the preface to an article, he goes back even further than the balloon. His favorite dream in very early childhood, he writes, before he could even read, was a dim consciousness of a realm without gravity, where one could move freely in every direction, more freely than a bird in the air. Where that desire came from, he could not say. He had never come across stories of the kind. He dimly perceived such a place, and longed for it.

There is something here, he admits, that he cannot explain. It seems to him, though he is not sure, that the urge to reach for the Sun and the desire to shed the bonds of gravity had been with him always.

The memory can be taken for what it is: the account a man of fifty-four gives of his childhood, at the moment he is trying to understand where his fixed idea came from. But it has its value. Tsiolkovsky does not present himself as an engineer who came to space through machines. He presents himself as a child who wanted to float.

The families, the moves

His early childhood was spent in Izhevskoye, then in Ryazan, where the family settled around 1860. In 1868, the father was transferred to Vyatka, a town in the northeast of European Russia, some eight hundred kilometers from Moscow. Konstantin was then ten, and his life had already been turned upside down.

For between the collodion balloon and the departure for Vyatka comes the event he would say decided everything else. At nine, he caught scarlet fever.

Sources: autobiography of K. E. Tsiolkovsky (1926) and letter of June 11, 1926, in N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (Leningrad, 1931), NASA translation TT F-646, 1971, p. 2; Tsiolkovsky’s preface to his 1911 article (Vestnik Vozdukhoplavaniya, no. 19), quoted by Rynin, p. 28; for family names and dates, the Russian and English Wikipedia entries (tertiary sources).

Chapter 2 · 1866 – 1873 Scarlet Fever

“When I was nine years old, I lost my hearing after having been sick with scarlet fever, and was regaining it very slowly.” Konstantin Tsiolkovsky tells what followed without self-pity. With children his own age and in company, he often found himself in awkward situations. His deafness made him appear funny. It alienated him from people. And, “out of sheer boredom,” he began to read, to withdraw into himself, and to daydream.

What deafness did

He would not remain completely deaf, but he would never hear well again. He followed a class poorly. That nearly closed school to him, and everything school opens.

At sixty-eight, he analyzed for himself what this infirmity had produced. First, a wound to his self-esteem. He had been hurt, he writes, and sought to assert himself. He entertained thoughts of great deeds. At eleven, he started writing poems he calls silly.

Next, a habit. Having no teachers and few books, he had to work things out alone. He grew so used to it that, faced with a textbook, it was easier for him to prove a theorem than to look up the proof in the book. He adds honestly that he did not always succeed.

Finally, a price to pay, which he never stopped feeling. His partial deafness from childhood, he writes, left him completely inexperienced in matters of everyday life and without any contacts. Perhaps that is why, he concludes in 1926, at sixty-eight he had not accomplished much and had had no notable success. The man who wrote that sentence had already published the equation that bears his name.

Vyatka, the gymnasium, his mother’s death

In Vyatka, he did enter the gymnasium, the classical secondary school, in 1869. According to his Russian biographers, he repeated a year there and left in 1873 without finishing. He himself says nothing of it in his autobiography, except this: his deafness deprived him of the opportunity to go to school, and he later had to take examinations to obtain his certificate.

In the fall of 1870, his mother died. He was thirteen. Of that, too, he says nothing to Rynin.

Lathes, a cart, a turbine

What he does tell about is his machines. At fourteen, he read in a physics textbook, that of the Frenchman Ganot, a few pages on balloons. He tried to inflate a tissue-paper bag with hydrogen. The experiment failed. It was around that time, he thinks, that he became interested in mechanical flight, with wings.

He made rudimentary lathes, on which things could really be turned. He built all sorts of machines. The most successful was a cart designed to be driven by the wind. The model worked beautifully. He set it on a board, on the roof of the house, and the cart moved against the wind. “My father was very pleased,” he writes. They used to bring him down from the roof so he could show the model to guests, indoors. There he made the wind with bellows, and the experiment succeeded too.

Encouraged, he started on a vehicle of his own size, to travel in himself. He bought nails and odds and ends with his breakfast money. The venture came to nothing. He gives three reasons, in this order: he ran short of patience and materials; he got tired of going hungry; and he realized that the whole thing was not going to work anyway.

At the same period, another of his models ran across the floor: a cart powered by a steam turbine.

The metal balloon

At about fifteen or sixteen, he learned elementary mathematics. He could then go more deeply into physics. Balloons still occupied him. He put a precise question to himself: how large must a balloon be, with an envelope of metal of a given thickness, in order to carry people?

He found the answer, and it struck him. The larger the balloon, the thicker its envelope can be. The volume, which lifts, grows faster than the surface, which weighs. By thinking big enough, one can therefore make a balloon entirely of metal.

“From then on the idea of a metal dirigible did not leave me.” It did not, indeed. He would tire of it at times, turn to other things for months, and always come back. He would give that airship, which was never built, as much effort as his rockets.

In 1873, his father decided to send him to Moscow. He was sixteen.

Sources: autobiography of K. E. Tsiolkovsky (1926), in N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 2–4 and 8–9; for the Vyatka gymnasium, his mother’s death, and the departure for Moscow, the Russian Wikipedia entry (tertiary source).

Chapter 3 · 1873 – 1876 The Night in the Streets of Moscow

He was sixteen, he was in Moscow, and he believed he had found the way to rise to the stars. The idea had come to him while studying centrifugal force. He was so worked up that he could not sleep. All night he wandered the streets, turning over in his head the implications of his discovery. By morning, he saw the flaw in his machine. “My disappointment was as strong as my exhilaration had been,” Konstantin Tsiolkovsky would write.

Three years of bread

His father had sent him to Moscow in the summer of 1873. According to his Russian biographers, he was to enter a technical school there. He did not. He stayed three years, and taught himself.

The same biographers describe a life of privation. He lived on ten to fifteen rubles a month and fed on bread and water. His days were spent in a public library. It has often been written that there he met the librarian and philosopher Nikolai Fyodorov, for whom humanity would one day have to leave the Earth and people the heavens. The dates make this uncertain, and Tsiolkovsky does not mention it in the account he gave Rynin.

What he himself says takes a few lines. He did not study systematically. He read only what could help him solve the problems that interested him and that he thought important. That is how he learned mathematics, out of necessity, problem by problem.

Centrifugal force

Among those problems, there was one he placed above the others: getting off the Earth. The Soviet historians who went through his papers confirm that his interest in interplanetary travel goes back to those Moscow years, between 1873 and 1876, long before he thought of the rocket.

His first tool was centrifugal force, the force that pulls outward an object being whirled. A stone in a sling tends to fly off. Could something not be spun fast enough for that force to overcome gravity and lift a machine? He believed so, for one night.

By morning, he saw that his invention had a basic flaw. He does not say which. One can only recall the law he would state himself ten years later: a closed machine does not move by its internal motions alone, any more than one lifts oneself by pulling on one’s own hair. Something must be thrown out.

The error was a fruitful one. Centrifugal force does not allow a takeoff, but it is indeed what keeps a satellite in orbit: launched fast enough horizontally, a body no longer falls back, because its tendency to go straight exactly balances gravity. Tsiolkovsky would use it in 1895 to describe an artificial moon of the Earth.

“I still have dreams”

That night mattered. “It had a lasting impact on me,” he writes. Thirty years later, he still had dreams in which he flew up to the stars in his machine, and felt in them the same excitement as on that memorable night.

In the same breath he tells of another youthful illusion. He devoted some effort to perpetual motion, the machine that would run forever without consuming anything. Fortunately, he says, he discovered within a few hours that he was proceeding from an improper understanding of magnetism.

Two false starts, then, and he admits both. That is his way. Tsiolkovsky never claimed to have been right the first time. He wrote more than once that, for lack of books, he had rediscovered things long known, and that he had often been wrong. But he gained by it, he adds, in developing his reasoning and his critical faculties.

The return

In 1876, his father brought him back to Vyatka. According to one reference entry, he was worried to see him wearing himself out. Konstantin was nineteen. He earned his living giving lessons in algebra and geometry.

He brought back from Moscow the habit of learning alone, higher mathematics included. He would say why he took it up. “The idea of traveling into outer space constantly pursued me. It prompted me to study higher mathematics.”

Sources: autobiography of K. E. Tsiolkovsky (1926), in N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 3–4; V. N. Sokolsky, in First Steps Toward Space, Smithsonian Annals of Flight no. 10, 1974, p. 269; for living conditions in Moscow, the library, and the return to Vyatka, the Russian and English Wikipedia entries (tertiary sources).

Chapter 4 · 1878 – 1879 The Ryazan Notebook

The archives of the Academy of Sciences preserve a school exercise book of eighteen pages. Konstantin Tsiolkovsky filled it in Ryazan in 1878 and 1879, at twenty-one and twenty-two, while he was waiting for a schoolmaster’s post. It contains sketches of vehicles and devices, diagrams, notes in pencil. It is the oldest document in which one sees his hand drawing space.

A family coming apart

In 1878, his father retired and the family moved back to Ryazan. It had shrunk. According to his Russian biographers, Konstantin had lost a younger brother, who died of typhus in Vyatka in 1876, and a sister the year before. His father would die in January 1881.

In November 1878, he was exempted from military service because of his deafness and nearsightedness. He needed a profession. He had no diploma. He chose the only one within his reach: schoolteacher.

Mice in a rotating machine

In the meantime, he experimented. The Soviet editors of his works have summarized what the notebook shows. Tsiolkovsky was wondering what strong acceleration does to a living being. He had built a rotary machine himself. He placed mice, chicks, and insects in it and spun them, to see what increase in their weight they could bear.

The year was 1879. No one was thinking of sending a living being into space. But he had already asked himself the question that would later govern the whole design of crewed ships: departure requires a sharp acceleration, and one must know what the body can endure. He had also understood that this can be found out without leaving the ground, by replacing the acceleration of a launch with that of a rotation. It is the principle of the centrifuges in which astronauts train.

The Soviet historian V. N. Sokolsky confirms the date: in 1878–79, Tsiolkovsky began his astronomical drawings and proposed a device for studying the effect of acceleration on living organisms.

What the notebook contains

The pages published in 1960 carry drawings with captions of a few words. They show that a projectile, thrown or falling, has no weight. They show that in a carriage starting or stopping, a horizontal gravity is added to the Earth’s gravity, and that the gravity felt becomes inclined. They show two people standing in the same room at right angles to each other. They show that a liquid set in rotation changes shape. And they show that in a space without gravity, motion along a curve gives rise to an apparent gravity, proportional to the curvature of the path and to the square of the speed.

All of this is correct. And all of it would be put to use. The apparent gravity created by rotation would become, in his books, the means of giving weight back to the inhabitants of stations. The weightlessness of a falling body would become the ordinary condition of life in orbit.

The editors see in these pages the rough drafts of a text he would write four years later, “Free Space.”

The examination

In September 1879, he sat as an external candidate for the examination that conferred the title of district schoolteacher. His Russian biographers have found the papers: religious instruction, Russian, arithmetic, and algebra. He passed.

In January 1880, he was appointed teacher of arithmetic and geometry at the district school of Borovsk, a small town in Kaluga Province, about a hundred kilometers southwest of Moscow. He was twenty-two. He would teach for forty years.

Sources: “Pages from a Young Man’s Notebook” and essay by B. N. Vorobyov, in K. Tsiolkovsky, The Call of the Cosmos (Moscow, 1960), pp. 453 and 471–472; V. N. Sokolsky, in First Steps Toward Space, p. 269; autobiography (1926), in N. A. Rynin, NASA trans. TT F-646, p. 4; for the family, the exemption, and the examination, the Russian Wikipedia entry (tertiary source).

Chapter 5 · 1880 – 1883 Twenty-Four Years Behind

In 1881, in the small town of Borovsk, a young schoolteacher finished a paper on physics. In it he established, from nothing, the theory that explains the pressure and heat of a gas by the agitation of its molecules. He sent it to St. Petersburg, to the Russian Physico-Chemical Society. The reply taught him that the theory already existed. Konstantin Tsiolkovsky would sum up the episode in a sentence: he had developed the theory of gases unaware that he was twenty-four years behind the times.

The arithmetic master

Borovsk is a small town in Kaluga Province. Tsiolkovsky taught arithmetic and geometry there at the district school. According to his Russian biographers, on August 20, 1880, in a nearby village, he married Varvara Yevgrafovna Sokolova, a priest’s daughter. The same biographers note that on his wedding day he bought a lathe.

They would have seven children. The first, Lyubov, was born in 1881. Then came Ignaty, Alexander, Ivan, Leonty, Maria, and Anna.

He would say that he had always been a dedicated teacher, and that he came home from school exhausted, having spent most of his energy there. Only in the evening could he make his calculations and conduct his experiments.

Three papers

At twenty-three and twenty-four, he sent the Physico-Chemical Society three works: a theory of gases, a mechanics of the animal body, and a study of the duration of stellar radiation.

He acknowledges it plainly: these works were out of date. Others had treated these subjects before him. In his isolation, he had no way of knowing it. Books were scarce, and few were accessible to him.

The Society could have sent him back to his pupils. It did the opposite. It treated him, he writes, with great consideration, and this encouraged him. Forty-five years later, he still names those who read him: “Perhaps they have forgotten me, but I still remember Borgman, Mendeleev, Van der Vliet, Bobylev, and especially Sechenov.”

Dmitri Mendeleev is the chemist of the periodic table. Ivan Sechenov was a great Russian physiologist. It was to him that Tsiolkovsky sent the first part of his study on the animal body. According to the Soviet editor of his stories, Sechenov took an interest in it and advised him to finish it. He would manage to do so only forty years later.

His biographers add that the Society admitted him as a member. A deaf schoolteacher with no diploma, living far from any scientific library, had just entered the world of science by mail.

What the lag was worth

To redo alone a theory twenty-four years old is no small thing. It proves one is capable of finding it. Tsiolkovsky drew from it an idea of himself that he would keep: he had no teacher, but he could follow a line of reasoning to the end.

He also drew from it a certain wariness. He wrote more than once that the lack of books had forced him to work everything out by himself, and that this had developed his critical faculties. He thinks he was always, by nature, an original. His deafness and the isolation it imposed only strengthened that bent.

The downside would show all his life. He used his own notation, Russian letters in his formulas, where everyone else writes in Latin letters. He illustrated his equations with tables of numbers, never with curves. The engineer Mikhail Tikhonravov, who would edit his works in 1947, noted that these habits make his texts hard to read for those who learned science in schools.

The steam engines

Between twenty-five and twenty-eight, he worked at improving the steam engine. He built one of metal, and another whose cylinder was of wood. Both were poorly built, he says, but they worked. He also made some fairly good air fans and various pumps. He did not sell them. He made them as an experiment, and for use in soldering and forging.

Then he gave up. He saw, he writes, how ineffectual he was technically when it came to putting his ideas into practice. The sentence is that of a clear-sighted man. He knew from then on that he was not a builder. His strength lay elsewhere: posing a problem, calculating it, and saying what the machine would have to be.

That is exactly what he did, in the spring of 1883, in a manuscript he would never publish.

Sources: autobiography of K. E. Tsiolkovsky (1926), in N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 4–5; B. N. Vorobyov, in The Call of the Cosmos (1960), p. 460; M. K. Tikhonravov, introduction to Works on Rocket Technology (1947), NASA trans. TT F-243, pp. 10–11; for the marriage, the children, and admission to the Society, the Russian and English Wikipedia entries (tertiary sources).

Chapter 6 · 1883 Free Space

“With all my strength, I threw a stone in the direction opposite to the one in which I wanted to go.” Konstantin Tsiolkovsky wrote that sentence in Borovsk, between February and April 1883. He imagines a man floating in a space without gravity and without air, who wants to move. He has nothing to push against. He has a stone left. It is, in his papers, the first text in which he describes how to move in a vacuum by throwing matter away.

The stone

The manuscript is entitled “Free Space.” That is what Tsiolkovsky calls a place where gravity is absent, or very weak. He applies to it the laws of motion of two bodies acting on each other.

The stone, he writes, leaves at ten meters per second. The man, a hundred times heavier than it, leaves in the other direction a hundred times more slowly, that is, at one tenth of a meter per second. The stone will continue on its way through space until it meets, perhaps in a thousand years, a large mass that attracts it. If it is not caught, it is lost forever.

He draws a law from this, which he puts in quotation marks: without loss of matter, motion in free space is impossible.

The barrel

Throwing stones one by one gives a jerky motion. So he moves on to a continuous jet. Take, he says, a barrel filled with a highly compressed gas. If one of its taps is opened, the gas escapes in a steady stream, and the elasticity of the gas, which pushes its particles out into space, also pushes the barrel, without interruption.

He goes further. With enough taps, six, he writes, the outflow of gas can be regulated so that the motion of the barrel depends entirely on the will of whoever works them. The barrel will follow any curve, at any pace.

He sees the limit at once. This motion at will lasts only as long as gas remains: minutes, hours, or days. After that, the barrel runs on in a straight line at constant speed, and nothing more can be done about it.

This six-tap barrel is exactly what engineers today call a cold-gas attitude control system. Satellites and crewed spacecraft orient themselves this way, by releasing small jets of gas through nozzles pointing in several directions.

The sketch of March 9

One page of the manuscript carries a drawing, dated March 9, 1883, by the Russian calendar. It is the cross-section of a ship. On the right, a cannon fires spherical projectiles: the recoil of each shot pushes the craft. In the center, gyroscopes, spinning tops whose rotation makes it possible to change the ship’s orientation in space without throwing anything away.

The text contains no trajectory calculation. The historian V. N. Sokolsky stresses it: there are no quantitative data, all the conclusions rest on qualitative reasoning, and Tsiolkovsky does not say how one would leave the Earth to get there. But the necessity of reaction is clearly understood and formulated in it. The manuscript also examines, Sokolsky notes, the conditions under which plants and living beings could exist and grow in that space.

Mikhail Tikhonravov, who published these excerpts in 1947, took care to add a reservation: what is described here is not the rocket, but the principle of motion in airless space is correctly indicated.

Thirteen years of oblivion

Tsiolkovsky did not publish “Free Space.” The text would stay in his papers. It would appear only in 1954, in the edition of his works by the Academy of Sciences.

He himself seems to have forgotten it. Tikhonravov says so bluntly: apparently, Tsiolkovsky thought no more of these pages, and thirteen long years went by before he returned to the subject. By then he was nearing forty. In the interval, he had given himself wholly to another machine, the one he had carried in his head since adolescence.

It may seem surprising that a man should hold in his hand, at twenty-five, the principle of spaceflight, and put it away in a drawer. But in 1883, he had no means of going from the principle to the project. A barrel of compressed gas does not leave the Earth. He lacked the calculation that would say how much matter must be thrown away, and at what speed, to reach the stars. That calculation he would make in 1897.

Sources: excerpts from “Free Space” (1883) quoted by M. K. Tikhonravov, introduction to K. E. Tsiolkovskiy, Works on Rocket Technology (1947), NASA trans. TT F-243, pp. 5–6; V. N. Sokolsky, in First Steps Toward Space, p. 270; facsimile and caption of the sketch in The Call of the Cosmos (1960), supplement; B. N. Vorobyov, same volume, pp. 453–454.

Chapter 7 · 1885 – 1887 The Metal Airship

In the spring of 1887, a provincial schoolteacher took the floor before the Society of Friends of Natural Science, in Moscow. He was twenty-nine. He had come to present the design of a dirigible balloon whose envelope would be made not of fabric but of metal. His manuscript ran to four hundred and eighty pages and eight hundred formulas. Konstantin Tsiolkovsky had not brought it: it was in the hands of a professor.

The decision of 1885

He dated the turning point himself. In 1885, at twenty-eight, he decided to devote himself to aeronautics and to the theoretical study of a metal dirigible. He worked on it for two years, almost without interruption.

He was short of time. School took his days and his strength. So he adopted a habit that says a great deal: he rose at dawn, worked on his treatise, then went off to teach. After two years of this regime, he suffered from headaches.

Why metal

The balloons of the time were made of varnished cloth. They leaked, they burned, they lost their shape. To go up or down, gas had to be released or ballast thrown out, and neither can be done indefinitely.

Tsiolkovsky imagined a hull of corrugated sheet metal. The corrugations run across the length. They allow the envelope to fold like a bellows: the balloon changes volume without tearing. Two beams run along the top and bottom of the hull. Cables stretched between them draw them together or apart, and in this way the shape and volume are adjusted.

The second idea is to heat the gas. The exhaust gases of the engines pass through pipes that cross the envelope. By regulating this heating, the lifting gas is expanded or contracted. The airship rises or descends without losing either gas or ballast.

Finally, everything is calculated so that the parts work only in tension. The hull is held in shape by the pressure of the gas it contains. It can therefore be thin and light. The same principle would later be recognized in the pressure-stabilized tanks of certain rockets.

Moscow

According to his Russian biographers, it was an inventor from the region, Pavel Golubitsky, who arranged his trip to Moscow. The talk took place before the Society of Friends of Natural Science. Tsiolkovsky remembered being treated there with kindness and understanding, in particular by a scientist named Yakov Weinberg.

A few objections were put to him. He answered them easily. He adds a remark of rare honesty: more serious objections could have been raised, but nobody did so, because the subject was little known and his manuscript was not there.

The manuscript had been handed by the physicist Alexander Stoletov, for review, to Nikolai Zhukovsky, the future founder of Russian aerodynamics. Tsiolkovsky did not consider his work finished. He even asked that it not be judged yet. What he asked for instead was to be transferred to Moscow, near the libraries and the scientists. He was promised it. For a reason unknown to him, the transfer never happened.

What became of the project

He went back to Borovsk. He would never let go of that airship again. In 1890, he would send a new study of it and a folding model to the Russian Technical Society, on Mendeleev’s recommendation. In 1892 and 1893, he would publish its description at his own expense. He would calculate versions for twelve, for a hundred, for two hundred passengers, then, in 1915, tables going up to aircraft eighteen hundred meters long.

None would be built. His biographer Rynin wrote in 1931: private institutions and the government allotted him some funds from time to time for his models, but, lacking steady support, he was never able to verify whether a full-size dirigible was feasible. The largest model, a brass hull ten meters long, would be made in Moscow in the mid-1920s.

The metal dirigible is the work to which Tsiolkovsky gave the most pages. It is also the one history has left aside. But it was in trying to find out whether the air would slow his balloon that he would build, ten years later, the first wind tunnel in Russia.

For the moment, he had presented his idea in Moscow. That same year, his house burned down.

Sources: autobiography of K. E. Tsiolkovsky (1926) and letter of June 11, 1926, in N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 2 and 5–6; Rynin’s description of the dirigible, same work, pp. 17–21; for the role of P. Golubitsky, the Russian Wikipedia entry (tertiary source).

Chapter 8 · 1887 – 1892 The Fire, the Flood, and the Dream of the Moon

“I fell ill, I lost my voice, a fire destroyed my small library and my models.” Konstantin Tsiolkovsky lines up these misfortunes in a single sentence, without a complaint. He adds only that the big manuscript on the dirigible was then in Moscow, with Professor Zhukovsky, and that he therefore still has it. Everything else he had made and collected in Borovsk over seven years went up in smoke.

Fire, then water

According to his Russian biographers, the fire took place on March 23, 1887. It started in a neighboring shed and spread to the house. The books, the instruments, the models were lost.

The following year, again according to them, the house where the Tsiolkovskys had resettled was invaded by the spring flood.

Tsiolkovsky said what he did in such cases. He always had a workshop at home. If that workshop was destroyed, by fire or by flood, he rebuilt it, and he enlarged it.

It took him a year to recover. “After a year I recovered somewhat and resumed my work,” he writes.

Two dreamers on the Moon

Yet it is from these dark years that his first story dates. The manuscript of “On the Moon” bears a note in his hand: he prepared it in Borovsk, in 1887.

The story begins with an awakening. The narrator, a young man with a passion for astronomy, has dreamed that he was bathing. It is winter. He gets up, and everything seems strangely easy. His feet barely touch the floor. He lifts the end of a bookcase full of books. He jumps, rises slowly, comes down the same way, jumps higher, and bangs his head on the ceiling.

His cry wakes his friend, a physicist, who goes through the same surprises. The narrator watches him do so with, he says, the greatest satisfaction. Then the two men try to understand. Have they become stronger, or has gravity diminished?

The physicist proposes a measurement. He braces his feet against the wall and pulls on a spring dynamometer: his strength has not changed. Then he hangs a twelve-pound weight on the same spring. The needle shows two pounds. Gravity is therefore six times weaker. He thinks for a moment and adds: that is exactly the gravity on the surface of the Moon.

They laugh. They draw back the curtains, which they had closed the night before because of the moonlight. The narrator recoils. The sky is blacker than the blackest ink, and the landscape is bathed in dazzling sunlight. There is no town anymore, no one.

A lesson in disguise

What follows is a journey. The two friends travel over the Moon, observe, make experiments. They note that the Sun appears the same size there as from the Earth, and deduce where they are: from Mars, it would look smaller, and Mars receives only half our heat. They discover the length of the lunar day, the burning of the sun, then the cold. The long night comes. They are about to freeze to death, when the narrator wakes up for good.

Tsiolkovsky peopled his Moon with plants and leaping animals, which hide in the crevices or run after the sun to escape the cold of the night. The Soviet editors of 1960, usually severe toward his fancies, found an excuse for these: they soften, they write, the picture of a nature that is otherwise harsh and pitiless.

The rest is exact physics. A weight weighed on a spring loses five sixths of its value, but a two-pan balance would show nothing, since both pans grow lighter together. The sky is black in broad daylight because there is no air to scatter the light. The reader of 1893 learned all this while believing he was reading a tale.

The Technical Society

In the fall of 1890, Tsiolkovsky returned to his airship. Through Mendeleev, he sent the Imperial Russian Technical Society a paper on the possibility of building a metal aerostat, and a model that folded down until it measured only about seventy centimeters.

He soon learned from the press that the Society had judged his calculations and ideas correct. Then he received a copy of the comments of the aeronautics department. They gave him, he writes, great pleasure. The matter would go no further than discussion. But it was the second time a learned society had told him he was right.

At the beginning of 1892, he was transferred. It was not Moscow, which he had been promised. It was Kaluga, the provincial capital, less than a hundred kilometers from Borovsk. He was thirty-four. He would never leave it again.

Sources: autobiography of K. E. Tsiolkovsky (1926), in N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 6 and 9; K. Tsiolkovsky, “On the Moon,” in The Call of the Cosmos (Moscow, 1960), pp. 10–17, foreword p. 6 and editor’s note p. 454; for the dates of the fire, the flood, and the transfer, the Russian Wikipedia entry (tertiary source).

Chapter 9 · 1892 – 1894 Kaluga

“I do not recall a greater joy than the one I felt, being in Kaluga, on receiving the proofs of my paper.” Konstantin Tsiolkovsky was thirty-four. He had just changed towns, and his study of the metal dirigible was about to appear in book form. One of his brothers and a few acquaintances had helped him publish it.

A slightly bigger town

Kaluga is a provincial town on the Oka, some hundred and sixty kilometers southwest of Moscow. Tsiolkovsky held the same job there as in Borovsk: teacher of arithmetic and geometry at the district school. According to his Russian biographers, his salary was thirty-six rubles a month. He had a wife and four children. A fifth, Leonty, was born that year and died the next, of whooping cough.

The town brought him what Borovsk could not give him: people. The Soviet editor of his stories, Boris Vorobyov, noted it: in Kaluga, he met persons connected with the world of letters, who took an interest in his research and tried to help him.

Their help was first of all that of the printer. The first part of his study on the dirigible metal aerostat had appeared in Moscow in 1892. The second was printed in Kaluga in 1893. Then his new friends placed, in the Moscow magazine Vokrug Sveta, “Around the World,” the story he had been keeping since Borovsk. “On the Moon” appeared in 1893, as a serial, then as a book.

Among these friends was, he would say himself, the nephew of the novelist Ivan Goncharov, the author of Oblomov. It was he who would publish in Moscow, two years later, his second book of scientific reveries.

The Kaluga pamphlets

From 1892 on, Tsiolkovsky never stopped publishing. His biographer Rynin drew up in 1931 the list of his printed writings. It fills four pages. It includes articles in journals of Moscow, St. Petersburg, and Odessa, but above all thin pamphlets bearing the imprint “Kaluga.”

Those pamphlets he paid for himself. The engineer Tikhonravov, who reissued them, did the count. They were printed in runs of about two thousand copies. They were not put on sale. Tsiolkovsky distributed them in person, to whoever asked. In thirty years, his works on rockets circulated, all editions combined, in only seven thousand five hundred copies.

He would explain himself on this. He had always fought for the right to publish his own works, in the hope that among the public there would be readers able to judge them correctly.

The airplane of 1894

In 1894, the journal Nauka i Zhizn, “Science and Life,” published a theoretical study by him entitled “The Airplane, or Bird-like Flying Machine.” It appeared as a pamphlet in Moscow the following year.

Rynin stressed the date. This was eight years before the first flight of the Wright brothers. No detailed study of the airplane then existed in Russia. In it Tsiolkovsky sets out a theory of flight, describes the structure of the machine, and calculates the power of the engine.

He built nothing. And he concluded, in the same article, in favor of the metal dirigible. A study of winged flight had shown him, he would say, that this kind of flight requires much more energy than he had first believed. On that point, the future would prove him wrong.

A signal to Mars

In 1896, the local newspaper, the Kaluzhsky Vestnik, published in its issue no. 68 an article by him with an astonishing title: “Will the Earth Ever Be Able to Inform the Inhabitants of Other Planets of the Existence on It of Intelligent Beings?”

The question was in the air. Since the Italian astronomer Schiaparelli drew lines on Mars in 1877, which were translated as “canals,” part of the public had believed the planet inhabited. Tsiolkovsky proposed a way of signaling to it: large mirrors that would send back the light of the Sun. He would take up the idea again in his novel, where the space travelers correspond with the Earth by mirror flashes.

In 1896, then, he was a provincial schoolmaster who had published a theory of the dirigible, a theory of the airplane, a lunar tale, and who wrote in his town’s newspaper about how to talk to the Martians.

Yet he had already written, the year before, the book in which he announces everything else.

Sources: autobiography of K. E. Tsiolkovsky (1926) and list of his writings, in N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 1, 6, and 9–12, 21; B. N. Vorobyov, in The Call of the Cosmos (1960), pp. 454 and 459; K. Tsiolkovsky, “Is This Mere Fantasy?” (1935), same volume, p. 470; M. K. Tikhonravov, introduction to Works on Rocket Technology (1947), NASA trans. TT F-243, pp. 10–12; for the salary and the children, the Russian Wikipedia entry (tertiary source).

Chapter 10 · 1895 Dreams of Earth and Sky

“I woke up with a dreadful sinking of the heart, the kind one feels when falling from a height. I threw off the blanket, and saw that the bed was standing on end. Yet I was not sliding off it.” So begins, in a book published in Moscow in 1895, the description of a house where gravity has vanished during the night. Konstantin Tsiolkovsky was thirty-seven. He had just invented, to explain it to his readers, the daily life of a man without weight.

A cautious book

The work is entitled Dreams of Earth and Sky, and the Effects of Universal Gravitation. Its publisher was the nephew of the novelist Goncharov. Tsiolkovsky would say that in it he expressed his ideas on space travel “cautiously.” There is no rocket in it yet. The aim is to make clear what gravity is, and what a world without it would be like.

He begins by giving the scale. If the Earth were a small pea five millimeters across, the Sun would be a huge watermelon, the Moon a grain of millet, Jupiter an apple, the asteroids grains of sand and dust. The whole atmosphere, on an Earth the size of a finger, would be only a film two and a half millimeters thick, and the layer in which man can breathe would be no thicker than cigarette paper.

Gravity has vanished

Then comes the awakening scene. The narrator wants to get dressed. He finds himself sliding toward the opposite wall. He can no longer tell floor from ceiling. He and his friend bump into everything, and everything they touch starts moving. The chairs, the table, the mirrors float about the room, “each in its own way.” The books open by themselves. The watch, caught by its chain, twists like a snake. The clock has stopped, and the pendulum refuses to start again. A jolt sends the water out of the carafe: it crosses the room as a quivering ball and bursts into drops against the wall.

Tsiolkovsky is enjoying himself. The trousers, he writes, float in a friendly embrace with a hat. The two men struggle “like flies in a lamp glass.” But every detail is exact. A pendulum clock runs only by gravity. A free liquid gathers into a ball. A body once pushed no longer stops. And one ends up getting used to it: the narrator notes that the sensation of falling comes less often, then disappears.

Three quarters of a century later, the first crews of orbital stations would describe the same thing. The book would be reissued twice in the Soviet period, under the title Gravity Has Vanished.

A moon three hundred kilometers up

Tsiolkovsky then looks for a real place where one would be without weight. He finds one. Let us imagine, he writes, a satellite of the Earth, like the Moon, but as close to our planet as you like, just beyond its atmosphere, that is, about three hundred kilometers from the surface. Everything on it would seem to escape gravity.

It is the first time he uses the idea of an artificial satellite. He immediately gives the figure that governs it: for centrifugal force to cancel gravity, a speed close to eight kilometers per second is needed. The first Sputnik, in 1957, would orbit at that speed.

But he does not yet know how to get there, and he says so in so many words. “So near and yet so far.” How does one get out of the atmosphere? How does one give a body eight kilometers per second? He reviews the means, and dismisses them one after another. A train launched at that speed around the equator: the air will never allow it. A platform girdling the Earth above the atmosphere: an absurdity. Jules Verne’s cannonballs?

He stops at a last image. A tower erected at the equator turns with the planet. The higher one climbs it, the weaker gravity becomes, and the greater the centrifugal force. At thirty-four thousand kilometers above the ground, he calculates, the two cancel out. Beyond that, one would be pulled upward. This impossible tower is the ancestor of what is now called the space elevator, and its altitude is roughly that at which our television satellites orbit.

What a body can bear

The book also contains his experiments. He spun insects until their weight was multiplied by three hundred. A cockroach underwent the same treatment and did not seem any the worse for it. He increased the weight of a chick several times, five times he seems to recall, without killing it. It would be interesting, he adds, to know what increase in gravity remains harmless for larger creatures, and above all for man.

He gives a means of protecting what is fragile, and an experiment for checking it at home. Take a glass of water, an egg, and some salt. Salt the water until the egg floats in it between top and bottom. Then strike the glass on the table, as hard as the glass allows: the egg does not move. Nature, he remarks, houses in the same way what is most delicate in her, the embryo, the brain, in a liquid. Could this method not be used? He would make of it, in his rocket designs, the bath in which the passenger lies to withstand the launch.

A glass sphere

Finally, he raises the question of life off the Earth. One of his characters imagines a glass sphere several meters across, reinforced with a steel lattice, or a steel sphere pierced with portholes. Soil, plants, oxygen, carbon dioxide, nitrogen, moisture are put inside. It races through the vacuum like an asteroid. The plants renew the air that the animals breathe.

Someone objects that this is too artificial. The reply has stayed: “Spectacles are not natural either, and yet you wear them. The more man progresses, the more he replaces the natural with the artificial.”

Satellite, orbital speed, gravity created by rotation, a closed greenhouse fed by the Sun, life on the asteroids: in 1895, the whole program is there. The vehicle is missing.

Sources: K. Tsiolkovsky, “Dreams of Earth and Sky” (1895), in The Call of the Cosmos (Moscow, 1960), pp. 53–54, 69–73, 84–85, 90–96; B. N. Vorobyov, same volume, p. 456; K. Tsiolkovsky, “Is This Mere Fantasy?” (1935), p. 470; N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 4 and 24–25; V. N. Sokolsky, in First Steps Toward Space, p. 270.

Chapter 11 · 1896 – 1901 The Wind in a Box

On a very windy day in Kaluga, a man is taking measurements on his roof. He wants to know the force the air exerts on an object. He notices that the resistance, in a strong wind, is lower than had been believed. “I nearly fell off the roof with excitement,” Konstantin Tsiolkovsky would write. The discovery vindicated his dirigible. Above all it would make him the first man in Russia to build a wind tunnel.

A useful quarrel

It all started with a dispute. Theorists maintained that the resistance of the air on a dirigible would be extremely strong. If that were true, his metal balloon could not move forward. Tsiolkovsky decided to check for himself. He ran his tests sometimes in his room, sometimes on the roof when the wind was blowing.

His experiments showed him that the resistance was not so high, and that the coefficient of resistance decreases as speed increases. But natural wind is capricious. To measure properly, one needs a steady stream of air, adjustable at will.

The machine

His biographer Rynin described the apparatus from Tsiolkovsky’s writings. A fan is set in motion by a descending weight, like that of a clock. The weight can be changed, from half a pound to sixteen pounds, and the force of the blast adjusted accordingly. The air comes out through a square nozzle thirty-five centimeters on a side. It reaches a little over five meters per second. To make it steady, it first passes through a grid twenty-five centimeters deep.

The object to be studied is placed in front of the nozzle, on a support that floats in a tank of water. Pushed by the air stream, the support pulls on a thread, and the thread bends a flexible needle in front of a graduated scale. Before the tests, Tsiolkovsky calibrates the scale with pulleys and weights.

He exposed to the blast plates set face-on, then inclined, plates more or less elongated, parallelepipeds, cylinders, polyhedra, spheres, hemispheres, cones, and the model of a dirigible balloon. He also measured the friction of air along a surface.

“It is truly astonishing,” Rynin writes, “that, under the conditions in which he worked, Tsiolkovsky was able to carry out such extensive and careful work, and to formulate with fairly good accuracy the fundamental laws of air resistance.” The engineer Tikhonravov would date this first Russian wind tunnel to 1897.

Fifty-five rubles

The tests cost money. Tsiolkovsky had none. In 1897, the Kaluga newspaper published an article about him by Pavel Golubitsky. The press picked up the story sympathetically, and readers sent donations for the progress of aeronautics.

He told what this did to him. In all, he received fifty-five rubles, which he spent on new experiments. But he accepted the money reluctantly, with a feeling of bitterness. Some donors had not understood the article, he writes, and gave out of simple charity. He even fell ill over it. He held on, in the hope of continuing. The sum, for all the noise made by the newspapers, was paltry. “Petersburg sent four rubles.” He consoled himself with the thought that this money, at least, was meant for aeronautics.

The Academy

In 1899, he published in Odessa, in a journal of experimental physics, the description of his apparatus and his results, under the title “The Pressure of Air on Surfaces Introduced into an Artificial Air Stream.” He sent this work to the Imperial Academy of Sciences.

Academician Mikhail Rykachev, who headed the physical observatory of St. Petersburg, gave a favorable opinion. The Academy granted Tsiolkovsky four hundred and seventy rubles to continue his experiments. That was roughly a year of his schoolmaster’s salary.

He built a larger wind tunnel, whose air stream was nearly seventy centimeters on a side. He made hundreds of tests on a large number of models. A year and a half later, he sent the Academy a report of eighty sheets, with fifty-eight tables and diagrams. An excerpt appeared in 1903 under the title “Air Resistance and Aeronautics.”

“Without a glimmer of hope”

It is about these years that he writes the saddest sentences of his autobiography. His experiments had given him many new results. But scientists, he says, greet new results with skepticism. Anyone could confirm them by repeating the same experiments. But when will that happen?

“It is hard to work all alone for many years, under unfavorable conditions, without a glimmer of hope, without any help.”

He adds, because he is fair, that he was sometimes understood. In Kaluga, a group of engineers recognized that his dirigible design was feasible. Should that not give hope that it will one day be recognized by all educated people?

While he was measuring the resistance of the air in this way, another question occupied him in secret. He had obtained, in 1896, a small pamphlet on a new way of flying.

Sources: autobiography of K. E. Tsiolkovsky (1926), in N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 6–8; description of the wind tunnel and the tests, same work, pp. 1 and 15–16; M. K. Tikhonravov, introduction to Works on Rocket Technology (1947), NASA trans. TT F-243, p. 6.

Chapter 12 · 1896 – 1898 The Formula

In the archives of the Academy of Sciences, a handwritten page bears a date: May 10, 1897. On it is an equation. It links the speed a rocket can reach to the amount of matter it throws away and to the speed at which it does so. Konstantin Tsiolkovsky was thirty-nine. He had just written the law that has governed, ever since, all flight in space.

Fedorov’s pamphlet

He told how he came to it. In 1896, he obtained a small pamphlet that had just appeared in St. Petersburg. The author was named A. P. Fedorov, and the title announced “a new principle of aeronautics.”

“The book did not seem clear to me,” Tsiolkovsky writes, “and in such cases I set about making my own calculations. I got nothing from the book. But it pushed me toward serious work.”

The passage is characteristic. Faced with an obscure text, others would have closed the pamphlet. He picked up a pencil. Thirteen years earlier, he had described a barrel of gas moving through the vacuum. He had forgotten it. Reading Fedorov brought him back to the same point, but with a new question: how much?

Before the rocket, doubt

One must picture what a rocket was in 1896. It was a cardboard tube filled with powder, fired on festive evenings or launched to carry a line to a ship in distress. Tsiolkovsky admits it: “For a long time I looked on the rocket as everyone did, as an amusement and an object of little use.”

He no longer remembers very well, he says, how the idea came to him of making calculations about it. He believes the first seeds were sown by Jules Verne, whose stories set his mind working in a certain direction. Then came desire, and after desire, the work of thought. But thought, he adds, would have led nowhere without the help of science.

What fascinates him, he specifies, is not the flight of a rocket. It is the exact calculations.

What the equation says

The reasoning takes few lines. A rocket, in a vacuum and far from any gravity, throws a little of its matter backward at every instant, always at the same speed. With each ejection, it gains a little forward speed. But it is also a little lighter, so that the next ejection, identical to the first, pushes it a little harder.

Adding up all these small gains, Tsiolkovsky finds a very simple law. The final speed of the rocket depends on two things only: the speed at which the gases come out, and the ratio between the mass of the full rocket and its mass once empty.

He immediately draws three consequences from it, which he would later formulate as theorems.

The first is a freedom. The final speed depends neither on the duration of the burn nor on its regularity. Whether everything is burned in a minute or in an hour, in bursts or in one go, the result is the same, provided the gases always come out just as fast.

The second is a promise. The speed of the rocket has no limit. By carrying enough matter to throw away, any speed can be reached, including those no cannon will ever give.

The third is a bill. That speed grows very slowly. When the mass of the full rocket becomes twice, four times, eight times, sixteen times, thirty-two times that of the empty rocket, the speed increases by only one notch each time: one, two, three, four, five units. The masses grow in geometric progression, the speeds in arithmetic progression. Each additional kilometer per second costs more than the one before.

The numbers

It remained to find out how fast the gases can come out. Tsiolkovsky chose the most energetic mixture he knew: hydrogen and oxygen, which in combining give water. He calculated the heat this reaction releases, and assumed that a sufficiently long tube, flared toward the exit, converts it almost entirely into motion. He found an exhaust speed of several kilometers per second.

With such gases, a rocket whose propellants weigh a few times more than the rest reaches the eight kilometers per second that put it into orbit, then the eleven that tear it away from the Earth. These are enormous proportions. They are not absurd proportions. A full barrel easily weighs ten times the empty barrel.

That is what the sheet of May 10, 1897, contains in embryo: the proof, by calculation, that one can leave the Earth with the means of ordinary chemistry.

August 25, 1898

He did not publish right away. In his papers, another page carries the final formulas of the reactive device, with the date August 25, 1898. He would mention it himself in 1911, adding: “Evidently, I was working on it even earlier.”

Meanwhile, he had begun a story. In 1896, the year of the pamphlet, he wrote the first chapters of Outside the Earth. In the third, a character proposes the rocket as a vehicle for space. The eighth tells of two rocket trials at the limits of the atmosphere. The tenth prepares a flight around the Earth. By the end of the year, he had nine or ten chapters. He stopped there, for twenty years.

Tsiolkovsky himself gave the key to this double writing, in a sentence of 1926: “First, inevitably, come the idea, the fantasy, the tale. Behind them walks scientific calculation. And in the end, execution crowns the thought.” He specified his place in that sequence: his work concerns the middle phase.

Sources: V. N. Sokolsky, in First Steps Toward Space, pp. 270–271 (manuscript of May 10, 1897, Archives of the Academy of Sciences); M. K. Tikhonravov, introduction to Works on Rocket Technology (1947), NASA trans. TT F-243, pp. 5–6; K. E. Tsiolkovsky, “A Rocket into Cosmic Space” (1903), same volume, pp. 32–35; preface of 1911 and theorems of 1914 quoted by N. A. Rynin, NASA trans. TT F-646, pp. 28–29 and 73–74; B. N. Vorobyov, in The Call of the Cosmos (1960), pp. 451 and 457.

Chapter 13 · 1903 The Article Nobody Read

In 1903, issue no. 5 of the journal Nauchnoye Obozreniye, “The Scientific Review,” published in St. Petersburg an article by a schoolteacher from Kaluga. The title is austere: “The Exploration of Cosmic Space by Means of Reactive Devices.” The text announces a drawing that was not printed. The formulas are full of errors, because the author did not read the proofs. Konstantin Tsiolkovsky had just founded the science of spaceflight, and almost no one noticed.

Neither balloon nor cannon

The article begins modestly, with a question of instruments. How high can a measuring device be sent into the atmosphere? Sounding balloons, he writes, have not risen above twenty-two kilometers. To go higher would take an envelope lighter than tissue paper. One will never get out of the air by balloon.

The cannon, then? He does the calculation. Imagine a cannon three hundred meters high, erected next to the Eiffel Tower, which is the same size. To launch a shell to an altitude of three hundred kilometers, it must leave the barrel at nearly two and a half kilometers per second. For a quarter of a second, everything the shell contains weighs a thousand and one times more than usual. A kilogram weighs a thousand. No instrument would withstand it. As for putting a living being in it, that is out of the question.

The advantages of the rocket

Then comes the proposal. In place of the cannon, Tsiolkovsky puts an elongated metal chamber, which carries with it a large reserve of two liquids. Mixed at the entrance of a tube, they burn, and the gases escape through this tube, which flares like a horn.

He lists the advantages, point by point. Compared with a giant cannon, the device is light as a feather, cheap, and easy to make. The thrust is steady, and it is adjusted at will: one can therefore choose the gravity the passengers will undergo, and safely send not only instruments but people. The speed increases as one wishes, in the direction one wishes. It can even decrease, which will make it possible to land gently on a planet. Finally, the rocket passes slowly through the lower layers of the air, where resistance is strong, and really accelerates only once it is up there.

Each of these four remarks answers a defect of the cannon. Together, they describe exactly the way a crewed spacecraft is launched today.

The machine of 1903

The description takes one page, and a drawing found in his papers, dated 1902, confirms it. The two liquids are hydrogen and oxygen, liquefied by cold. They occupy most of the hull. At the front are the people, with light, oxygen to breathe, and something to absorb the carbon dioxide they give off.

The tube in which the mixture burns is surrounded by a jacket. The icy liquids circulate in it before being burned, and so cool the wall. It is the principle all the great engines would use.

To steer the craft, Tsiolkovsky proposes several means. A mass can be shifted inside. The end of the tube can be swiveled. A rudder can be placed in the jet of gas, at the exit. Forty years later, the engineer Tikhonravov would point it out: the German V-2 rocket was steered by graphite vanes plunged into the jet, exactly as he had proposed.

To hold the course without human intervention, he provides for automatic devices. One tracks the image of the Sun through a lens: if the craft turns, the spot of light moves and triggers a mechanism that restores the direction. Another is a gyroscope, a small chamber containing two disks spinning very fast in different planes, which keeps its orientation relative to the stars. He writes in so many words that automatic instruments will be needed to regulate the motion of the rocket and the force of the explosion according to a program fixed in advance.

Then come the equations: the formula of 1897, vertical flight under the effect of gravity, oblique ascent, efficiency.

A small-circulation journal

The journal that published this text was a review of philosophy and science, edited by Mikhail Filippov. Tsiolkovsky would say himself that it had a small circulation. According to the Soviet editor of his stories, it was banned by the police shortly afterward, and the sequel to the article did not appear.

The result was silence. The article, the same editor writes, went unnoticed. In America, Robert Goddard was twenty and had not yet published anything. In Transylvania, Hermann Oberth was eight. Neither would know anything of it for a long time.

That same year, 1903, on December 17, the Wright brothers flew their airplane on a beach in North Carolina. The whole world would eventually learn of it. It would take twenty years for it to learn what had appeared in St. Petersburg in the spring.

Tsiolkovsky by then had other reasons to suffer. The year before, he had lost a son.

Sources: K. E. Tsiolkovsky, “A Rocket into Cosmic Space” (1903, text of 1924), in Works on Rocket Technology (1947), NASA trans. TT F-243, pp. 24–35, and introduction by M. K. Tikhonravov, pp. 8–9 and 13; N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 31–33; V. N. Sokolsky, in First Steps Toward Space, pp. 270–271; B. N. Vorobyov, in The Call of the Cosmos (1960), p. 457; K. Tsiolkovsky, “Is This Mere Fantasy?” (1935), same volume, p. 470.

Chapter 14 · 1902 – 1910 Grief and Genius

In 1916, in Kaluga, Konstantin Tsiolkovsky had a pamphlet printed to which he gave this title: Grief and Genius. Only the title concerns us here. Its two words sum up the fifteen years he had just lived through.

Ignaty

His Russian biographers give the facts, which he himself kept silent. His son Ignaty, the second of his children, was born in Borovsk in 1883. In 1902, he took his own life. He was not yet twenty.

Tsiolkovsky says not a word about it in the notes he sent his biographer in 1926. He writes only, in conclusion: “It is pointless to talk about oneself and the small things of life when there are so many problems to solve, so many works to finish or publish.”

This silence is not indifference. It is that of a man who lost, before he died, five of his seven children. Leonty died in infancy in 1893. Ignaty in 1902. Ivan would die in 1919, Anna in 1922. Alexander, like his brother, would end his own life in 1923. Only Lyubov and Maria would outlive him.

The house of 1904

In 1904, again according to his biographers, he bought a house on the edge of Kaluga. He would live there nearly thirty years. It is now a museum, and the street bears his name.

He set up his workshop there in a glazed veranda, on the upper floor. A small door of that veranda opens onto the sloping roof of a lean-to. The family named it “the door to the cosmos.” On fine evenings, when the sky was clear, he carried out through it his small amateur telescope, mounted on a tripod, and looked at the stars from the roof.

His wife and the neighborhood children, who often came by, also liked to look through the telescope. He would then gather them around him and tell them about the constellations, the planets, the nebulae, and the shooting stars. The editor of his stories, Boris Vorobyov, who reports the scene, sees in it the origin of several of his texts: they have the tone of those talks he gave to people close to him.

The flood of the Oka

In 1908, the Oka overflowed. The house was flooded. One reference entry states that a large part of the papers accumulated over the years was lost.

It was the second flood of his life, after the one in Borovsk, and the third destruction of his workshop, after the fire of 1887. He reacted as he wrote: he rebuilt, and he enlarged.

The schoolmaster

He still earned his living by teaching. He gave lessons in mathematics and physics at the diocesan school for girls in Kaluga. He would stay there until his retirement.

He loved the job, and he said so. True, because of his deafness, he talked more than he listened during his lessons. True, he did not like examinations. “But I liked teaching.” Only, school absorbed all his strength and left him very little energy for his studies and projects. He wrote, calculated, and built mostly on holidays and during vacations.

He counted his pupils: in nearly forty years, about five hundred boys and two thousand girls learned arithmetic, geometry, or physics with him. The disciples who would make his fame never had him as a teacher: they read him.

“My hernias”

He continued his experiments on air resistance. From 1905 to 1908, he published in a St. Petersburg journal a long study of two hundred and sixty pages entitled “The Aerostat and the Airplane.” In 1910 and 1911, he returned to his dirigible, whose advantages he defended in several pamphlets. In 1913 and 1914, he built models of it in corrugated sheet metal.

All of this was done by hand, in the veranda. He would sum up his life in a sentence: it had been nothing but reflection, calculations, manual work, and experiments. In parentheses, he adds a detail few scientists would have admitted: from that manual work, he even got two hernias.

During those eight years, the article of 1903 lay dormant. Nobody asked him for the sequel.

Sources: autobiography of K. E. Tsiolkovsky (1926) and list of his writings, in N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 4, 8–11, and 21; B. N. Vorobyov, in The Call of the Cosmos (1960), pp. 460–462; for the children, the house of 1904, the flood of 1908, and the diocesan school, the Russian and English Wikipedia entries (tertiary sources).

Chapter 15 · 1911 – 1914 “What Is Impossible Today”

“To set foot on the soil of the asteroids, to lift with one’s hand a stone from the Moon, to build moving stations in ethereal space, to form inhabited rings around the Earth, the Moon, and the Sun, to observe Mars from a distance of a few dozen versts, to descend on its satellites or even on its own surface: what could be more insane!” Konstantin Tsiolkovsky wrote this in 1911, in an aviation journal of St. Petersburg. He was fifty-four. This time, he was read.

Eight years later

In 1911, aviation was in fashion. Russia had its first airfields, its first builders, its first journals. One of them, the Vestnik Vozdukhoplavaniya, “The Aeronautics Herald,” agreed to publish the sequel to the article of 1903. It appeared as a serial, from issue no. 19 of 1911 to issue no. 9 of 1912.

The editors presented it cautiously. They pointed out the scale of the difficulties and the strangeness of a medium the author claimed to enter. But they published, with the drawing of the rocket, which readers saw for the first time.

The effect, writes the Soviet editor of his stories, was enormous. Tsiolkovsky at once attracted disciples, whose number grew quickly, in Russia and beyond. He himself would date from 1913 the beginning of his recognition abroad.

The picture of the flight

The second part is very different from the first. The equations are there, but it contains above all a description. Tsiolkovsky entitles one chapter “Picture of the Flight,” and takes the reader along.

Everything is ready, he supposes. We are sitting in the rocket, our friends are watching us. The signal is given. The explosion begins, with a deafening noise. The rocket shudders and is off. Our weight is multiplied by ten. “I have fallen to the floor, knocked myself out, or even died: this is no time for making observations!” There are means of withstanding this gravity, he specifies, in particular immersing oneself in a liquid.

This hell lasts one hundred and thirteen seconds. Then the noise stops, a deathly silence sets in, and gravity disappears as quickly as it came. We are at an altitude of five hundred and seventy-five kilometers.

There follows the weightless world, which he has known since his Dreams of 1895. Water no longer pours from the jug. The pendulum hangs askew. Oil shaken out of its bottle forms a perfect ball. The scales are of no use anymore: gold can no longer be sold by weight. One floats in the middle of the cabin like a fish, effortlessly. “We feel well, light, as if lying on the softest of feather beds.”

The shutters are opened. Two skies are seen. One half is black, with stars that do not twinkle and the Sun. The other is yellowish, scattered with light and dark patches: it is the Earth. It does not look convex. It looks hollow, like the inside of a bowl. As one moves away, it becomes a large dish, then a saucer, then a moon.

Those who stayed on the ground, for their part, saw the rocket rise like a stone falling upward. After half a minute, it is at forty kilometers, and can still be followed with the naked eye: heated by the friction of the air, its skin shines like a star.

Then he describes the maneuver that changes everything. Once up there, the rocket is swung around and the engine relit, this time horizontally. The rocket no longer falls back. It circles the Earth, like the Moon. “We can now be completely at ease: the rocket has become a satellite of the Earth.”

Radium and electrons

He also looks further than chemistry. It had just been discovered that radium disintegrates, throwing off particles at prodigious speeds. If one knew how to speed up that disintegration, he notes, a pinch of radium would be enough to tear a one-ton rocket away from the solar system, and the nearest star would be reached in ten to forty years.

He adds a second lead: it may be that in time electricity will be used to give an enormous speed to the particles thrown out by the rocket. That is, in one sentence of 1911, the principle of the ion engine. He concludes simply: future discoveries may show that there is nothing in it, but it is good to be able to dream of it right now.

Between two and sixteen

The text ends with a passage he entitled “What Is Impossible Today Will Become Possible Tomorrow.” That is where the sentence about the stone from the Moon and the surface of Mars is found.

He recalls there that not so long ago, illustrious scientists regarded as madness the idea of knowing the composition of the stars. It is known today, through the analysis of their light. The idea of going to study them up close will seem madder still. And yet, he writes, it is only when reactive devices are used that a great new era of astronomy will begin.

Does gravity not frighten us more than it should? A shell leaving a cannon at two kilometers per second does not astonish us. Why should a projectile launched at sixteen kilometers per second, which would leave the solar system forever, terrify us? “Is there such a great gulf between the numbers two and sixteen? The one is only eight times greater than the other.”

It was in a letter of the same year, according to one reference entry, that he is said to have written his most famous sentence. It appears in any case in his texts on the future of spaceflight, which his biographer Rynin quoted: “The planet is the cradle of reason, but one cannot live in the cradle forever.”

The theorems of 1914

In 1914, he had a supplement printed in Kaluga. He wanted, he says, to give a popular account of his ideas, and to refute the opinion that the rocket was something very remote from us in time. In it he summarizes his theory in a few theorems.

He also responds there, for the first time, to a foreign scientist. The Frenchman Robert Esnault-Pelterie had set out, in 1912, his own calculations on a reactive device. Tsiolkovsky learned of them through a Russian journal. He takes up the Frenchman’s figures, corrects a power value, and compares Esnault-Pelterie’s rocket with his own. He was no longer alone in the world, and he knew it.

A few months later, the war broke out. He would publish no further scientific work on rockets for ten years.

Sources: K. E. Tsiolkovsky, “The Investigation of Universal Space by Means of Reactive Devices” (1911–1912) and supplement of 1914, in Works on Rocket Technology (1947), NASA trans. TT F-243, pp. 72–77 and 94–101, with the facsimile of the page of the Vestnik Vozdukhoplavaniya; N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 28–30 and 73–74; B. N. Vorobyov, in The Call of the Cosmos (1960), p. 457; “Is This Mere Fantasy?” (1935), p. 470; for the letter of 1911, the English Wikipedia entry (tertiary source).

Chapter 16 · 1917 – 1923 The Lubyanka and the Pension

On November 17, 1919, in Kaluga, agents of the Cheka, the political police of the new regime, arrested an old deaf schoolteacher. He was sixty-two. He was taken to Moscow and locked up in the Lubyanka, the central prison of the police. Konstantin Tsiolkovsky stayed there several weeks. Official Soviet history never spoke of it. It is known only from documents made public after the end of the USSR.

Two revolutions

In 1917, Russia changed regimes twice. The tsar abdicated in March. The Bolsheviks took power in November. The civil war began. Everything was in short supply, down to paper for printing.

For Tsiolkovsky, the new power first brought an honor. In 1918, according to one reference entry, he was elected a member of the Socialist Academy, which the Bolsheviks had just founded in Moscow.

The arrest

Then came November 1919. The sources say little. The historian Anatoly Zak summarizes what the archives have yielded: Tsiolkovsky was accused of anti-Soviet writings, he spent several weeks in the Lubyanka, and he was released on the intervention of a high official.

No more is known here, and it would be dishonest to say more. He himself makes no allusion to it in the account of his life he sent Rynin in 1926.

That same year, 1919, his son Ivan died. In 1922, it was his daughter Anna. In 1923, his son Alexander took his own life, like Ignaty twenty-one years earlier. In four years, he had buried three children.

Retirement

In the early 1920s, he stopped teaching. He cited his health. He was over sixty.

In 1921, the state granted him a personal pension for life. The historian Sokolsky recorded its exact terms. It was awarded to him “in view of the great merits of the scientist-inventor, specialist in aviation and aeronautics.” No mention is made of his research on rockets and interplanetary travel. For the government of 1921, Tsiolkovsky was the man of the metal dirigible.

That pension changed his life. For the first time since 1880, he no longer had to teach to feed his family. He could, Sokolsky writes, devote himself entirely to research. He was sixty-four. He had fourteen years left, and during those years he would publish several pamphlets a year.

Before and after

Soviet authors made much of this contrast. Before the October Revolution, Sokolsky writes, he was regarded as an eccentric, a gifted but unlucky autodidact, without a diploma. Afterward, the attitude changed completely. The engineer Tikhonravov, in 1947, sets against the “old caste of diploma-holding scientists of tsarist Russia” the recognition brought by the new regime, and quotes a letter in which Tsiolkovsky writes to Stalin: “Only October brought recognition to the works of a self-taught man.”

The contrast is real, but it needs qualifying on both sides. Under the tsar, Tsiolkovsky was not persecuted. He was ignored. The country’s greatest scientists, Mendeleev, Stoletov, Zhukovsky, Rykachev, read him kindly, and the Imperial Academy gave him money. What he lacked was an institution to take him on.

Under the Soviets, he was pensioned, housed, decorated, published. He was also arrested. And, as Anatoly Zak notes, he was celebrated as a theorist of space while being silenced as a philosopher. His ideas about the universe, as we shall see, did not fit the official doctrine.

The manuscript of 1921

What did he do with his freedom? The historians of the Academy of Sciences found, filed among his writings on the universe, a notebook entitled “The Expansion of Man into Cosmic Space.” It begins on September 21, 1921.

In it Tsiolkovsky draws up the list of the means of reaching cosmic speeds. He counts four: throwing out gases, solids, or liquids; a flow of electricity; the pressure of light rays; the radiation of matter, that of radium for example. On October 11, he specifies the use of each: the pressure of light for moving in the vacuum, engines for crossing the atmosphere and gaining the initial impetus.

On October 27, 1921, he notes for himself: “It is necessary to begin writing the complete theory of the rocket.”

That notebook settles a quarrel. It has been written, especially outside Russia, that he returned to rockets only in 1923, stung by Hermann Oberth’s book. The dates show that he had returned to them of his own accord, two years earlier. He had, moreover, during those years of scarcity, done something more astonishing still. He had finished his novel.

Sources: V. N. Sokolsky, in First Steps Toward Space, pp. 274–275; M. K. Tikhonravov, introduction to Works on Rocket Technology (1947), NASA trans. TT F-243, pp. 7–8; autobiography (1926), in N. A. Rynin, NASA trans. TT F-646, p. 8; A. Zak, “Konstantin Tsiolkovsky,” russianspaceweb.com, and “Konstantin Tsiolkovsky Slept Here,” Air & Space/Smithsonian, September 2002; for the date of the arrest, the Socialist Academy, the pension of 1921, and the children, the Russian and English Wikipedia entries (tertiary sources).

Chapter 17 · 1896 – 1920 Outside the Earth

In 1920, in Kaluga, the local Natural History Society published a small book in an edition of three hundred copies. Paper was scarce, the country was in the midst of civil war. The book is entitled Vne Zemli, “Outside the Earth.” Its author had begun it in 1896 and taken it up again twenty years later. The action takes place in the year 2017. In it Konstantin Tsiolkovsky tells, chapter after chapter, how people leave their planet, settle in orbit, and set out to explore the solar system.

A castle in the Himalayas

The story opens in the highest mountains in the world. A castle is hidden there. Six scientists live in it in seclusion: a Frenchman, an Englishman, a German, an American, an Italian, and a Russian. Disappointment with people, Tsiolkovsky writes, has led them to solitude. They have found happiness in science. They are immensely rich and can afford any experiment.

He gave them names. The Italian is called Galileo, the Englishman Newton, the German Helmholtz, the Frenchman Laplace, the American Franklin. The Russian is simply called Ivanov. It is he who, one summer evening, bursts into the great glazed hall at the top, disheveled, sweating, and hugs his colleagues until they cry for mercy. “We reach the Moon in four days! We leave the atmosphere in a few minutes!”

They think him mad. Franklin supposes he has invented a giant cannon, an old and impracticable idea. Ivanov grows impatient: it is a cannon, if you like, but a flying cannon, with thin walls, that fires gases instead of shells. A rocket. The Italian is disappointed: a rocket is only a toy. Newton, for his part, thinks it over.

The Soviet editor of the text, Boris Vorobyov, stressed the meaning of this casting. It is not a mere literary device. Tsiolkovsky means that the conquest of space will be the common work of several peoples, and not the isolated effort of a single country.

The rocket of 2017

The scientists first build a test craft: a metal spindle twenty meters long and two wide, with three pilots in padded seats. On the first trial, it hangs in the air for twenty minutes. On the second, it climbs to five kilometers.

Then comes the real ship. It is a hundred meters long and four in diameter. It is made up of twenty simple rockets joined together, each with its reserve, its chamber, and its tube, around a central compartment of twenty meters reserved for the crew. Its hull has three skins: strong metal pierced with quartz portholes, a layer that conducts heat poorly, and an outer skin of refractory metal that glows red during the passage through the air. Twenty men take their places in it.

To withstand the departure, they lie in cases full of liquid and breathe through a tube. They are in them, Tsiolkovsky writes, like swimmers. They can move their arms and work levers placed within reach. An automatic device, on which the orders for several minutes have been recorded in advance, carries out the maneuvers untouched.

On board, there are airtight suits for going out into the vacuum or into the unbreathable atmosphere of another planet. There are, for moving about there, small reaction tubes fixed to a harness. There is oxygen at reduced pressure, devices for absorbing the waste products of breathing, reserves of water and food. And there are seeds.

The greenhouse

This is the great idea of the book. Once in orbit around the Earth, the travelers go out in suits and assemble, beside the rocket, a greenhouse five hundred meters long and two meters in diameter. It is connected to the ship by airlock passages and by two pipes. One sends in the carbon dioxide and the crew’s wastes. The other brings back the oxygen the plants have produced.

The soil is held in a long container pierced with holes, watered from inside. A window runs the whole length. The plants grow in a light that never goes out. Fruits and vegetables ripen. The crew no longer depends on the Earth for eating or for breathing.

Tsiolkovsky goes further. Once people are used to living this way, they build inhabited greenhouses a thousand meters by ten, for a hundred persons each. The materials come up from the Earth by rocket, and workers in suits weld them on the spot. Then these greenhouses are assembled into stars, into clusters, into colonies.

The harvest of meteoroids

Materials are expensive to bring up. So the travelers look for them on the spot. As they move away from the Earth, they meet small blocks of rock and metal circling the Sun. Men in suits, equipped with their small engines, chase them and bring them back in nets.

The catch is analyzed: iron, nickel, silica, oxides. Newton shows the collection to his companions. Here, he says, is an excellent building material, the oxygen we lack, and soil for the plants. The oxygen is combined with other substances, but it is there, and the Sun gives the energy to extract it. Franklin adds that water can also be drawn from these rocks.

Ivanov concludes: if the composition of this world so resembles that of ours, what prevents it from becoming the dwelling place of man and the theater of his activity?

The editors of 1960 made fun of these butterfly nets: a pebble that strikes a ship at several kilometers per second is not plucked, it punches through. But the central idea has made its way. It is now called in-situ resource utilization, and it governs every plan for a lasting settlement on the Moon and on Mars.

A novel read by engineers

Three hundred copies is very few. Vorobyov nevertheless maintains that the book was known even outside Russia. In 1923, when Tsiolkovsky read Hermann Oberth’s booklet, he himself listed what is found in it that already appeared in Outside the Earth: the space suits, the compound rocket, the tethering of people and objects, the black sky, the stars that do not twinkle, the mirrors, the light signals, the base off the Earth from which one sets out farther, the journey around the Moon.

In this novel, the scientists go to the Moon. They also go, much farther, to the approaches of another planet. And there, they do something novelists never do. They decide not to land.

Sources: K. Tsiolkovsky, “Outside the Earth,” in The Call of the Cosmos (Moscow, 1960), pp. 161–166 and 257–259; foreword to the same volume, p. 7; B. N. Vorobyov, same volume, pp. 457–459; N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 11, 28, and 35–40 (description of the rockets and greenhouses of 2017).

Chapter 18 · 1894 – 1920 “Mars Will Not Run Away”

The ship is ten million kilometers from Mars. The planet appears as a miniature Moon. Through the telescope, one can make out its “canals,” its “seas,” its hills, the whiteness of its poles. The travelers have been gone for years. The leader of the expedition speaks: “We shall go no closer to Mars. Landing on the planet would be a dangerous undertaking. We are all tired.” One of his companions adds: “Mars will not run away. We shall reach it on a later expedition.” Konstantin Tsiolkovsky wrote this scene in Kaluga, between 1916 and 1920. It says everything about his way of thinking of the Red Planet.

The Mars of 1894

He had taken an interest in it long before. In 1894, in a manuscript that remained unpublished until 1960, he sends a narrator traveling from planet to planet. The page on Mars begins with numbers. Mars is one and a half times farther from the Sun than the Earth. A Martian field receives half as much heat as an earthly field. Gravity there is two and a half times weaker: objects weigh two fifths of their weight. Two small moons light its nights. The nearer one, Phobos, crosses the sky so fast that it rises in the west and sets in the east.

Then he gives a temperature. He estimates the average at thirty-two degrees below zero Celsius. Many then imagined a temperate Mars, with seas and vegetation. Space probes have measured an average close to sixty degrees below zero. Tsiolkovsky was still too optimistic, but he was on the right side.

From this cold he draws a consequence. Once, he writes, when the Sun was hotter and the planet still warm, the waters of Mars filled depressions, like our seas. Then the weather changed. They froze where they lay and became a solid part of the crust. Under the equatorial sun, this ice melts a little on the surface. The vapor gives a few snow clouds. At night, the whole planet is covered with white frost, which disappears shortly after daybreak.

The famous “canals,” he concludes, are not the works of engineers. They are those seas and rivers petrified by frost.

The explanation is wrong in detail: the canals did not exist, they were an illusion of the observers. But the overall picture is astonishingly accurate. A planet that had liquid water in its youth, that lost it as it cooled, and where it survives in the form of ice: that is, more or less, what geologists say of Mars today.

The manuscript then turns to fancy. The narrator meets “altogether charming” Martians, for whom this visitor from a warm world is a well-stoked stove. Households fight over him. Tsiolkovsky liked such jokes. His Soviet editors judged them severely.

The voyage of 1920

Twenty-five years later, in Outside the Earth, there are no more Martians. There is an engineer’s problem.

The colonies established between the Earth and the Moon are short of materials. Bringing them from the Earth costs too much. The Moon is not suitable. Newton therefore proposes to explore space beyond the Earth’s orbit, between the Earth and Mars, where one may hope to find small asteroids invisible from our telescopes. Before leaving, he checks one point: will it not be too cold there? He calculates that a black surface exposed to the Sun, at the distance of Mars, can still reach eighty-three degrees Celsius. One will therefore be able to live there in greenhouses.

The ship moves away from the Sun in a long spiral, engine idling. Each turn lasts more than a year. The greenhouse follows, attached, and supplies the food. The travelers discover hundreds of small bodies a few kilometers across or less. They land on one of them, nine hundred meters wide, where a man and his equipment weigh almost nothing. They find gold, silver, and platinum there, almost pure.

Ivanov draws from this a reflection that goes beyond metallurgy. If these blocks are the debris of a shattered planet, the Earth could be shattered one day. It would therefore be better for humanity to settle elsewhere without waiting for such a catastrophe. The idea that the species must have more than one world to survive, heard today from the advocates of Mars, is written there.

The decision

After several years, Mars is close. And it is then that Newton gives up.

The scene that follows is entitled “Can the Planets Be Visited?” A young member of the crew is enthusiastic: we live very well here, almost as far from the Sun as Mars, why not go there? Newton answers with a physics lesson.

He draws up a table of temperatures. For a planet, which radiates from its whole surface, the calculation gives Mars twenty-three degrees below zero. Taking into account the share of light it reflects, one falls to minus thirty-five. “It is therefore difficult to accept,” he says, “that with an average temperature of minus thirty-five degrees, the canals and seas of Mars are made of liquid water.” The average there is forty-nine degrees lower than on the Earth, a good part of which is already covered with eternal ice. “Then where would the water come from?”

A young listener asks sadly whether mirrors could not save them from the cold. They could, Newton answers, especially if there is no atmosphere. But an icy wind chills everything, and that is very hard to overcome.

Then he turns to the air. What gases will surround us when we land on an unknown planet? Suits and a reserve of oxygen would protect us from deadly gases. But who guarantees, he says, that our suits and our bodies will not perish in a Bengal fire?

His conclusion is that of the whole book. “I reject nothing. I only mean that we shall have to prepare ourselves by long and painstaking work, if we want to hope to triumph over the hostile forces of nature. Otherwise, they will crush us without even noticing us.”

The return

A vote is taken. The ship turns back. It does not retrace the outbound spiral. It cuts across by a short route, braking, and rejoins the Earth’s orbit in four months.

Before splashing down in the Indian Ocean, Ivanov sends a light telegram. We have explored the space between the orbits of the Earth and Mars, he announces. We have found hundreds of small planets there. They offer an inexhaustible source of materials for establishing colonies. No one was hurt, we lacked nothing. Life in space is wonderful.

He adds a plea, in which one hears the author: spare us the celebrations. Support instead the geniuses who are among you. You know very few of them, but there are more than you think.

In his final report, Newton lays out the program. The colonies will be transferred little by little between the orbits of the Earth and Mars. The Earth will no longer manufacture anything but rockets for transporting people. And those rockets, Tsiolkovsky writes in 1920, will be able to come back with fuel manufactured “up there.”

What this means

Tsiolkovsky, then, did not dream of a landing on Mars. He was even wary of it. In the list of steps he would draw up in 1927, he would write that landing on the large planets is so difficult that the question is, for the moment, beside the point. He saw the future of humans in space itself, in dwellings circling the Sun, fed by its light and built with the matter of the asteroids. Mars was for him a landmark, the boundary of the habitable region, and a world to be studied up close: he said so in 1911, it will first be observed from a few dozen versts, people will descend on its satellites, then, perhaps, on its surface.

But his caution amounts to a program. He posed, before anyone else, the three questions that must be settled before going: what temperature, what water, what air. And he gave the order of operations. First settle in space. Then go and look. Only then, descend.

Sources: K. Tsiolkovsky, “Changes in Relative Weight” (manuscript of 1894), section “Mars,” in The Call of the Cosmos (Moscow, 1960), pp. 377–380; “Outside the Earth” (1920), chapters 48 to 57, same volume, pp. 309–331; foreword, p. 6; Tsiolkovsky’s introduction (May 14, 1927) in N. A. Rynin, NASA trans. TT F-646, p. 27; “The Investigation of Universal Space” (1911), NASA trans. TT F-243, p. 96. For the average temperature of Mars and its water history: NASA.

Chapter 19 · 1923 – 1929 Twenty Years Under a Bushel

In 1924, in Kaluga, Konstantin Tsiolkovsky had his article of 1903 reprinted. He changed its title. “The Exploration of Cosmic Space by Means of Reactive Devices” became “The Rocket into Cosmic Space.” It is, almost word for word, the Russian translation of the title of a book that had appeared in Munich the year before: Die Rakete zu den Planetenräumen, by a certain Hermann Oberth. The old man was protesting in his own way.

The news from Germany

He was sixty-six when he learned that a German teacher had just published the theory of the liquid-fuel rocket, with stages, space suits, the station, and the journey around the Moon. The press spoke of it as a discovery.

He read the book, and made the list. “Oberth has many things that are found in my Outside the Earth,” he notes: the space suits, the compound rocket, the tethering of people and objects, the black sky, the stars that do not twinkle, the mirrors in space, the light signals, the base off the Earth from which one sets out farther, the journey around the Moon, the three-hundred-ton manned rocket, the study of the Moon, and many others.

The engineer Tikhonravov explained the title change of 1924: Tsiolkovsky adopted the almost literal translation of Oberth’s title to protest against the fact that the latter’s book was being received as a novelty, when he himself had proposed the same ideas in 1903.

“The fate of thinkers”

In 1926, he published a recast edition of his major work. He prefaced it with a text whose title is a complaint: “The Fate of Thinkers, or Twenty Years Under a Bushel.” In it he complains of the oblivion in which his works had been left.

A letter found in his papers says what he really thought. He had always been told that his ideas were “untimely.” He replies that all great undertakings have been. Railroads seemed untimely; commissions of scientists even judged them harmful to health. The steamboat was taken for a toy by the great Napoleon himself. History shows, he writes, that neither scientists, nor specialists, nor sages have ever known how to tell a great discovery from a small one.

There is bitterness in these lines, and also an accusation: the right to speak, he says, belongs only to the strong, to established authorities, and to scientists with diplomas. All others are stifled by that caste.

But he could also put things in perspective. “Priority exists today and disappears tomorrow,” he would write. And again: “I have never claimed a complete solution of the problem.”

What Germany gave back to him

The paradox is that Oberth’s book saved him from oblivion. As long as the space rocket was only the idea of a Russian schoolteacher, no one in Moscow cared. As soon as it became a subject of lectures in Berlin and Vienna, Soviet Russia remembered that it had a forerunner. The historian Anatoly Zak says it bluntly: it was in 1923, after Oberth’s publication, that the Soviet state “rediscovered” Tsiolkovsky.

Societies for the study of interplanetary travel were formed. Talented popularizers, Yakov Perelman and Nikolai Ryumin, explained his ideas to the general public. In Leningrad, Professor Nikolai Rynin undertook an encyclopedia of interplanetary flight in nine installments, and devoted an entire one to him. Tsiolkovsky sent him his autobiography in 1926, and in 1927 an introduction written for the purpose.

Abroad, too, he was read at last. A Russian student in Berlin, Alexander Scherschevsky, the very one who would assist Oberth, presented his rockets in German journals. A German engineer, Lademann, discussed his work of 1926 in an aeronautics journal, and contested the idea of vanes placed in the jet. Tsiolkovsky answered him in a pamphlet of 1927. On that point, the facts would prove him right fifteen years later.

The letter of 1929

Oberth, for his part, behaved well. He had heard of the Russian in 1924. In 1925, he received the retitled pamphlet from Kaluga, and had it translated for him by one of his pupils. He acknowledged the priority.

On October 24, 1929, he wrote to Tsiolkovsky. The letter was published, in excerpts, as an appendix to a Kaluga pamphlet. “I greet you… I hope you will live long enough to see your great goals accomplished… You have kindled the light, and we shall go on working until the great dream of mankind is realized… I am sending you my new book, and I would be very grateful if you would send me your latest works in exchange.”

The new book was Wege zur Raumschiffahrt. Rynin was then preparing its Russian translation.

So, in six years, the priority quarrel turned into a correspondence. Each said what he had to say: Oberth that the Russian had kindled the light, Tsiolkovsky that his own work stopped at calculation.

Three men

Tsiolkovsky himself drew up, in 1927, the list of those he regarded as the pioneers. It begins with Nikolai Kibalchich, the Russian revolutionary who in prison, in 1881, drew a powder-driven craft. It includes Ganswindt, Esnault-Pelterie, Hohmann, Oberth, Valier, Goddard, Tsander, Rynin. He underlined the names of those whose work he knew best.

Then he adds the sentence that fixes his place, and that no one disputes: until his works of 1903, the rocket was considered only for flight in the air. Only afterward did anyone think of using it to leave the atmosphere.

Rynin, who publishes this list, appends a historian’s note. The idea of going to the heavenly bodies by rocket is older than Tsiolkovsky: it is found in Cyrano de Bergerac. The merit of the scientist of Kaluga is to have been the first to found it on calculation.

Sources: M. K. Tikhonravov, introduction to Works on Rocket Technology (1947), NASA trans. TT F-243, pp. 6–9 and 13 (title change, letter on “untimeliness,” Oberth’s letter of October 24, 1929, polemic with Lademann); B. N. Vorobyov, in The Call of the Cosmos (1960), p. 458; N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, preface and pp. 26–28, 41–43; H. Oberth, “My Contributions to Astronautics” (1967), in First Steps Toward Space, p. 136; A. Zak, russianspaceweb.com.

Chapter 20 · 1926 – 1929 The Plan

On May 14, 1927, in Kaluga, Konstantin Tsiolkovsky wrote a three-page introduction for Rynin’s book. In it he sets out in twelve numbered points the sequence of operations that will lead humanity from the test stand to the colonization of the solar system. He was sixty-nine. No liquid-fuel rocket had yet flown in Russia. The list he drew up that day is, more or less, the one history began to follow thirty years later.

Twelve steps

This project, he warns, still belongs to pure speculation. Here, nevertheless, is how it might be carried out.

One: static tests, the engine fixed to the ground. Two: a reactive machine, loaded with instruments, running along an airfield. Three: a short hop into the air, followed by a gliding return. Four: the upper atmosphere, up to the stratosphere. Five: a machine that leaves the atmosphere and comes back gliding.

Six: stations in orbit outside the atmosphere, “like small moons near the Earth.” Seven: the use of the Sun’s energy for breathing, feeding, and living. Eight: the use of that energy for traveling throughout the planetary system, and for industry.

Nine: visits to the smallest bodies of the solar system, asteroids and planetoids. Ten: the establishment of bases on those bodies. Eleven: bases on the small moons and small planets. Here he adds a parenthesis: landing on the large planets is so difficult that, in his view, the question is for the time being beside the point. Twelve: the colonization of the whole solar system.

The first steps were climbed, in other forms, between 1926 and 1961, from Goddard’s trials to the first orbital flights. The sixth dates from 1971. That is where we are. Tsiolkovsky had warned: it will probably take centuries.

The work of 1926

This introduction summarizes a large work. In 1926, he had published in Kaluga a new, greatly enlarged edition of his Exploration of Cosmic Space by Means of Reactive Devices. Rynin notes that, under cover of “a few corrections and additions,” the book in fact deals with entirely new subjects, which Western authors had taken up in the meantime, and on which Tsiolkovsky sets his own stamp.

It contains a general theory of propulsion, in which he compares sources of energy. Chemistry first. Then energy received from outside, by radiation. Then that of radium: the mass to be thrown away would be minute, but the efficiency wretched. He shows that a rocket makes the best use of its energy when it throws out its gases at a speed equal to its own.

It also contains the departure. He does not believe that a rocket must tear itself from the ground vertically. He imagines a metal track built in high mountains, inclined at ten to twenty degrees, several hundred kilometers long. A “terrestrial rocket” a hundred meters long slides along it, accelerating, carried on a cushion of compressed air that almost eliminates friction. It carries on its nose the “cosmic rocket,” twenty meters long. At the end of the track, at more than three kilometers per second, the small one separates and goes on alone. The big one brakes and stops. It carries no crew.

It is a two-stage rocket whose first stage stays on the ground. The track was never built. But the idea of a first stage that does not fly off, or that comes back, has never ceased to tempt engineers.

The station and the return

The plan of conquest proper takes a few lines. First a station is built a thousand or two thousand kilometers from the Earth. It accumulates solar energy for distant flights. From there, one reaches the asteroids, where landing presents no great difficulty. The asteroids, he writes, are a source of fuel for the journey to other planets and to the stars.

To return to Earth, the rocket describes lower and lower spirals, then glides in the air like an airplane. The best thing, he specifies, is to have it come down in the ocean. In a manuscript of 1924 that a journal had turned down, he had already proposed braking in the atmosphere instead of burning fuel. All returns from space are made that way.

As for food, each rocket will carry plants that will purify the air and bear fruit. He does the count: a man needs three thousand calories a day. It would be enough to capture a small share of the rays striking one square meter exposed to the Sun.

The rocket trains

In 1929, he published a pamphlet with a vivid title: Cosmic Rocket Trains. A rocket train is an assembly of several similar rockets. The first fires until exhausted, then detaches. The second ignites, and so on. The last reaches the speed needed to escape.

This is the principle of stages, which Oberth and Goddard had described before him in their publications. Tsiolkovsky brings the calculation to it. He determines, for trains of two, three, four, or five units, the mass of fuel, the speeds, the duration of thrust. He places the driving rocket at the head, not the tail, because an assembly holds up better when pulled than when pushed.

In 1930, he described a jet airplane able to fly at an altitude of thirty-seven kilometers and at three thousand six hundred kilometers per hour. He saw the space rocket as the culmination of a line of ever faster airplanes, with ever smaller wings. One of his articles is entitled: “From the Airplane to the Spaceship.”

The train without wheels

Among his pamphlets of those years there is also an invention that has nothing to do with space. In 1927, in Air Resistance and the Express Train, he proposes a wheelless railcar. Engines blow compressed air under the floor. The car rises a few millimeters above the track and glides on this cushion, almost without friction. The air thrown out backward pushes it.

Historians have shown that he had been thinking of it since 1921: his notebook of that year already contains the principle of sliding “on a liquid or on a gas.” The hovercraft would be built only in the 1950s, in England.

“Time will tell”

He had no illusions about the time it would take. Authorities, he writes in 1927, have committed themselves to saying that interplanetary travel is possible, and in the near future. Can this be seen as a guarantee of success? Unfortunately not, as history shows. There have been so many worthless inventions supported in good faith by competent people, and so many others held to be nothing that proved precious.

“One works and hopes, and only life itself settles the questions and the doubts. Time will tell.”

Sources: introduction by K. E. Tsiolkovsky (Kaluga, May 14, 1927) and account of his works of 1926–1930 in N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 23, 26–28, 46–47, and 75–105; M. K. Tikhonravov, introduction to Works on Rocket Technology (1947), NASA trans. TT F-243, p. 13; V. N. Sokolsky, in First Steps Toward Space, p. 275. Modern reference points: NASA (first crewed orbital flight, 1961; first orbital station, 1971).

Chapter 21 · 1925 – 1933 The Philosopher of Kaluga

“There is no end to the life, the evolution, and the improvement of mankind. Man will always progress. And if that is so, he must surely attain immortality.” These sentences are not a poet’s. They close a text by Konstantin Tsiolkovsky on the prospects of rocket flight. For him, the rocket was never a goal. It was the means to a far vaster idea, which he set out in dozens of pamphlets that few engineers have read.

Why leave

One must first understand the reasoning, which is simple. The Earth receives only a minute share of the Sun’s light: one two-billionth, he calculates. All the rest is lost in the void. Yet that light is energy, and the space around the Sun is boundless. A humanity that knew how to live there would have two billion times more energy and unlimited room.

“Is it unreasonable to think of using that energy?” he asks. “Or of using the limitless space that surrounds the Earth?” He adds, for the skeptics: in any case, there is nothing wrong in developing such ideas, provided they are the fruit of serious work.

Then comes duration. The Sun will go out one day. It will then be logical to leave it for another, younger one. The journey will take tens of thousands of years. That is enormous for a man, he writes, but minute on the scale of humanity. The travelers will live in a manufactured environment, and their descendants will arrive. “The greater part of mankind, in all likelihood, will never perish, but will move from sun to sun as they die out.”

It is in this text that his most quoted sentence is found: the planet is the cradle of reason, but one cannot live in the cradle forever.

The beings of the ether

He pushes the reasoning as far as biology. Advanced societies, he observes, live in an increasingly artificial setting, and that is what progress means: protecting oneself from the weather, from animals, from microbes. In space, this artifice will be carried to the extreme.

But in time, he thinks, the new conditions will give rise to new beings. Aquatic animals came out of the water and became land animals. Land animals learned to fly. In the same way, after the conquest of the air will come that of the ether: the beings of the air will become beings of space.

His writings of those years bear titles that state their ambition: Monism of the Universe and The Cause of the Cosmos in 1925, The Future of the Earth and Mankind and The Will of the Universe in 1928, The Aims of Astronautics in 1929, Scientific Ethics in 1930. Rynin lists them without comment.

What his editors said of it

The Soviet scientists who reissued his stories in 1960 kept their distance, in a foreword that does not spare the great man. Tsiolkovsky, they write, lets his imagination run away with him when he describes the life of intelligent beings on Mercury, on Mars, or on the asteroids: these are pure fancies.

They point out errors. He believes in the “ether,” the fluid that nineteenth-century physicists supposed to fill space. He underestimates the danger of meteorites. He thinks a body could be protected from any acceleration by immersing it in water. He peoples all the planets, whatever their temperature and atmosphere, and imagines organisms made of any elements whatever, without seeing the unique role of carbon. He supposes that the Sun will cool in a few million years, because the true source of its energy was unknown in his time.

These criticisms are fair. They do not touch the essential. The same editors acknowledge it: the idea of a balance between plants and animals in large ships, which would allow journeys of indefinite length, is extremely interesting and deserves close examination with a view to carrying it out.

The imposed silence

There is another reason why this part of his work stayed in the shadows. A living universe, a humanity promised immortality: these ideas sat poorly with official materialism.

The historian Anatoly Zak summed up the situation in a phrase: the Soviet state celebrated Tsiolkovsky as a theorist of space, and silenced him as a philosopher. His Kaluga pamphlets, printed in a few thousand copies and distributed by him, passed from hand to hand.

The historian Sokolsky, writing in Moscow in 1968, hinted that the last word had not been said. The view taken of Tsiolkovsky has already changed four times, he notes. A time may come when more attention is paid to his works on the cosmos, and when his works on interplanetary flight will appear as no more than a particular case within a general theory of the conquest of the universe by mankind.

Where are they?

One last feature shows the reach of his thinking. According to a study published in 1995 in a British astronomy journal, he formulated in 1933, in a short note, what would later be called the Fermi paradox. If the universe is full of inhabited worlds, as he believes, why do we see no sign of them?

In Outside the Earth, he had given an engineer’s answer to a related question: the planets of other stars are too small and too dark to be seen. We perceive only the suns.

One may smile at his shivering Martians and his green-winged inhabitants of the asteroids. It would be wrong to forget that it was for them, and for the future they stood for, that he calculated the rocket. Without the philosophy, there would have been no equation.

Sources: Tsiolkovsky’s texts on the prospects of rocket flight, autobiography, and list of his writings, in N. A. Rynin, K. E. Tsiolkovskii, Life, Writings, and Rockets (1931), NASA trans. TT F-646, pp. 8, 11–12, and 29–31; foreword to The Call of the Cosmos (Moscow, 1960), pp. 5–9, and “Outside the Earth,” p. 177; V. N. Sokolsky, in First Steps Toward Space, p. 276; A. Zak, russianspaceweb.com; for the note of 1933 (V. Lytkin, B. Finney, and L. Alepko, Quarterly Journal of the Royal Astronomical Society, 1995), the English Wikipedia entry.

Chapter 22 · 1930 – 1934 The Patriarch

“Dear Sir, since the day of its founding, the Society for Space Travel has always regarded you as one of its spiritual leaders, and has never missed an opportunity to point out, by word of mouth and in the press, your merits and your indisputable priority in the development of this great idea.” The letter came from Berlin. It was addressed, in September 1932, to an old man in Kaluga celebrating his seventy-fifth birthday. Konstantin Tsiolkovsky had become, for those who build rockets, a living ancestor.

The Kaluga mail

Letters arrived from everywhere. On April 28, 1930, he drafted a collective reply, under the title “To Inventors of Reaction-Propelled Machines.” It begins: “Adults and children send me hundreds of designs for reactive means of locomotion. To all of them, I can give the following answer.”

The answer is a lesson in common sense. A reaction engine is efficient only if the craft goes about as fast as the gases it throws out, that is, at one or two kilometers per second. No car, no boat can travel at that pace: the resistance of air or water prevents it, and the wheels would burst. So one must fly, and fly high, where the air is thin. One necessarily arrives at the rocket plane of the stratosphere. But that is too complicated a task for children. There is a research institute for that.

He nevertheless enclosed drawings of simple models, which anyone can build without complicated tools. His editor notes that he took a great interest in the handiwork of the children at the local technical center.

Those who build

That institute did indeed exist. Around 1930, groups of engineers formed in Moscow and Leningrad to study reactive propulsion. The Soviet editors cite among his closest successors Friedrich Tsander and Valentin Glushko, who designed the first Soviet liquid-propellant engines. In 1933, the first Soviet liquid-fuel rockets rose. Among the young people who launched them were Mikhail Tikhonravov, who would edit his works, and Sergei Korolev, who would put Sputnik into orbit.

Tsiolkovsky had given up all practical research. He was then writing, according to his editor, a voluminous treatise on reaction engines, which his health constantly interrupted. He went on publishing: in 1932, a study of the “semi-reactive stratoplane” and another on reactive motion; in 1933, a work on rocket fuels and a turbine design. One of his last manuscripts, dated 1935, deals with the maximum speed of a rocket.

In 1934, his selected works appeared in Moscow. The second volume, devoted to reactive propulsion, had been prepared by Tsander, who had died the year before. It was printed in fifteen hundred copies.

Seventy-five years

The birthday of 1932 was celebrated officially. According to his Russian biographers, the government awarded him the Order of the Red Banner of Labor. The following year, he was assigned a new house in Kaluga.

Among the messages received, historians have singled out that of the German society, already quoted. A little later came a letter from the head of the Reaction Scientific Research Institute, founded in Moscow in 1933. It says what a whole generation owed him: “It is no secret that most of those who work on rockets today first became acquainted with the principles of reactive propulsion in your wonderful books, learned from them, and took from them your enthusiasm and your certainty that our cause will be crowned with success.”

Yet the historian Sokolsky makes a remark that corrects the picture. For most people, he writes, Tsiolkovsky’s name remained attached, as before, to aeronautics and dirigibles. It was the father of the metal dirigible who was being celebrated, more than the father of astronautics.

The model

The dirigible, as it happens, was not forgotten. In the mid-1920s, a brass model of its hull, ten meters long and two high, was built in Moscow from his plans. It occupied the large workshop of a university. “It is very impressive,” he wrote to Rynin, “and it makes me believe in the possibility of a metal dirigible. I really do not know whether this work will continue.”

In 1930, he again published the design of a metal dirigible for forty passengers, a hundred and twenty meters long. He himself warns that these dimensions are insufficient. Rynin concluded the same year, soberly, that for lack of steady support he had never been able to verify whether the machine was feasible at full size.

Eleven people

Rynin gives, in a note to his biography, a domestic detail. In 1931, Tsiolkovsky’s household numbered eleven people: his wife, aged seventy-two; an unmarried daughter of forty-eight; another daughter with her six children; and the orphaned child of a third daughter, deceased.

A photograph of 1928 shows him with a grandson. The old man who wrote about the colonization of the asteroids thus lived surrounded by children, in a full house, fed by his pension.

He had written to Rynin, in 1926, what he thought of his life, and he had not changed his mind. “My main task still lies ahead of me. Shall I have enough strength, shall I be able to complete my projects?”

Sources: V. N. Sokolsky, in First Steps Toward Space, pp. 275–276 (messages for the 1932 jubilee); K. Tsiolkovsky, “To Inventors of Reaction-Propelled Machines” (April 28, 1930) and essay by B. N. Vorobyov, in The Call of the Cosmos (1960), pp. 462–468; M. K. Tikhonravov, introduction to Works on Rocket Technology (1947), NASA trans. TT F-243, table of contents and pp. 11–12; letter of June 11, 1926, and notes by N. A. Rynin, NASA trans. TT F-646, pp. 2, 8–9, and 20–21; for the decoration of 1932 and the house of 1933, the Russian Wikipedia entry (tertiary source).

Chapter 23 · 1935 The Last Summer

On July 23, 1935, the newspaper of the Communist youth, Komsomolskaya Pravda, published an article signed by a man of seventy-seven. “Nothing absorbs me more than the problem of overcoming the Earth’s gravity and flying in space. I am already seventy-eight, and yet I go on calculating and drawing reaction machines.” Konstantin Tsiolkovsky had less than two months to live. The article is entitled “Is This Mere Fantasy?” In it he talks about a film.

The cinema

Some ten years earlier, he recounts, it had been proposed that his story Outside the Earth be brought to the screen. The business had proved too complicated, and was dropped. Now the Mosfilm studios, in the person of the talented Vasily Zhuravlyov, had decided to shoot Cosmic Voyage. Tsiolkovsky was its scientific consultant.

He is unreservedly glad of it. The cinema, he writes, reaches more people than books. It is more alive and closer to nature than a description. It is the summit of art, especially now that sound has been added to it. He finds it very courageous of Mosfilm to have undertaken such a film.

One thinks of the other film, shot in Berlin six years earlier, for which Hermann Oberth had been the consultant. The two theorists had the same experience: explaining to filmmakers how one floats in a cabin.

What tales are for

The article contains a confession. He often tried to write stories of space travel. Each time, he ended up being caught by the exact calculations, and went back to serious work. Fiction, with him, was always the rough draft of science.

But he defends it. Science-fiction stories about interplanetary voyages carry new ideas to the masses. All who devote themselves to this do useful work: they arouse interest, set the brain in motion, and form people who will sympathize with great projects and later work on them.

He also gives, in passing, two dates. He was seventeen when he first dreamed of leaving our planet. And it was from 1913 that his works were recognized abroad.

“In a few decades”

The most remarkable passage comes at the end. Does he himself believe in space travel? Will man ever achieve it?

The more he worked, he answers, the more difficulties and obstacles he met. Until recently, he thought it would take hundreds of years to fly at astronomical speeds, from eight to seventeen kilometers per second. The meager results obtained at home and abroad confirmed it.

But the uninterrupted work of recent times has shaken that pessimism. Methods have been found, he writes, that will give astonishing results in a few decades.

He wrote that in July 1935. The first satellite would be launched twenty-two years later, and the first man would go into space twenty-six years later. For once, he had seen too short in the other direction: all his life, he had said “centuries.”

The letter

He was ill. According to his biographers, he was suffering from stomach cancer. He was operated on.

On September 14, 1935, Pravda published a letter from him, addressed to Stalin and to the Central Committee of the party. “All my life, I have dreamed of moving mankind forward, if only a little, by my works.” In it he bequeaths all his writings on aviation, rockets, and interplanetary communications to the Bolshevik party and the Soviet government, “true leaders of the progress of human culture.” He declares himself certain that they will bring this work to a successful conclusion.

The engineer Tikhonravov quoted another sentence from it: “Only October brought recognition to the works of a self-taught man.”

This letter must be read with what is known of the period. In 1935, no text addressed to Stalin and published in Pravda was a simple private letter. Yet it says two true things. The first is that the pension of 1921 had freed him from school. The second is that he had not founded a scientific school to which he could pass on his papers. To bequeath his papers to the state was to make sure they would not be scattered. They were not: they are in the archives of the Academy of Sciences.

September 19

Konstantin Tsiolkovsky died in Kaluga on September 19, 1935, two days after his seventy-eighth birthday. He was buried in a public garden of the town.

The press announced his death. The government decided to honor his memory. And the historian Sokolsky, going through these texts, made a striking observation. Neither the communiqué on his death nor the government’s decision mentions his works on rockets. It was the inventor of the metal dirigible who was being buried.

His house became a museum the following year.

Sources: K. Tsiolkovsky, “Is This Mere Fantasy?” (Komsomolskaya Pravda, July 23, 1935), in The Call of the Cosmos (Moscow, 1960), pp. 469–471; B. N. Vorobyov, same volume, pp. 452 and 464 (letter published in Pravda of September 14, 1935); M. K. Tikhonravov, introduction to Works on Rocket Technology (1947), NASA trans. TT F-243, p. 8; V. N. Sokolsky, in First Steps Toward Space, p. 276; for the illness, the operation, and the burial, the Russian and English Wikipedia entries (tertiary sources).

Chapter 24 · 1935 – 1967 The Four Faces

On October 4, 1957, a Soviet rocket placed in orbit a metal sphere fifty-eight centimeters across. It circled the Earth at nearly eight kilometers per second, the speed Konstantin Tsiolkovsky had calculated in 1895. Seventeen days earlier, Moscow and Kaluga had celebrated the hundredth anniversary of his birth.

Four times a different man

The historian V. N. Sokolsky retraced, in 1968, the way Tsiolkovsky was spoken of over the course of the century. The portrait changed four times.

Before the revolution, he was an eccentric: a talented autodidact, without a diploma and without success.

From 1917 to his death, he was a specialist in aviation and aeronautics, the inventor of the metal dirigible. It was in that capacity that he was pensioned in 1921 and buried in 1935.

Ten years passed. The Second World War showed what a liquid-fuel rocket can do. Only then, Sokolsky writes, did people begin to speak of him above all as the founder of the theory of reactive propulsion and a pioneer of rocket technology. His works on aeronautics were almost forgotten. It was in 1947 that the engineer Mikhail Tikhonravov, himself a rocket builder, gathered his writings on the subject into one volume. He notes in his preface that the German V-2, with its liquid oxygen, its pumps, its automatic devices, and its vanes in the jet, carries out almost point by point what Tsiolkovsky had described in 1903.

Another ten or fifteen years, and the satellites, the probes to the Moon, Mars, and Venus, and human flight in space changed the figure again. He became the founder of cosmonautics: the first who had the courage to announce that mankind would not remain on the Earth forever, and who proved it scientifically.

The official hero

The Soviet Union made him a national hero. The Academy of Sciences published his works: it was in the second volume, in 1954, that “Free Space” appeared for the first time, seventy-one years after it was written. A monument was raised to him in Moscow in 1957. In Kaluga, Yuri Gagarin laid in 1961 the first stone of a museum of the history of cosmonautics, wanted by Sergei Korolev. It opened in 1967 and bears his name.

In 1959, the Luna 3 probe photographed the far side of the Moon for the first time. One of the most remarkable craters discovered there was given the name Tsiolkovsky.

This glory has a reverse side, which historians after 1991 have brought to light. The official image was too smooth. It erased the arrest of 1919. It erased the philosopher, whose ideas were inconvenient. It contrasted too simply the scientist humiliated by tsarism with the scientist showered with favors by the Soviets. And it tended to make him the inventor of everything, which he had never claimed to be.

What he really did

Tikhonravov, who admired him, put things with an engineer’s clarity. Tsiolkovsky’s works were purely theoretical. He carried out no practical work on rockets. Many of his calculations are very approximate and must be handled with caution. It is doubtful that engineers will use his formulas to build anything.

But, he adds, many of his technical ideas will undoubtedly be used. And he was the first to see, clearly, what the rocket would make possible.

The list of what he saw is long. The liquid-propellant rocket, hydrogen and oxygen. The cooling of the chamber by the propellants. The pumps. The vanes in the jet. Automatic guidance by gyroscope. The rocket of several units. The artificial satellite and its speed. The station in orbit, assembled on the spot. The space suit and the reaction harness. The greenhouse that regenerates the air. Gravity created by rotation. The protection of the crew at departure. Braking by the atmosphere on return. The use of materials found on the spot. The electric engine and the light sail.

None of these things was built by him. Almost all of them have been built.

The three fathers

It was long disputed which of Tsiolkovsky, Goddard, or Oberth deserved the title of father of astronautics. The question makes little sense. Each did what the other two did not.

Tsiolkovsky was first, by ten to twenty years. He found the equation and described the machine. But he wrote in Russian, at his own expense, in a provincial town, and no one read him in time outside his country. His work did not set the movement going: it joined it.

Goddard built. He flew the first liquid-fuel rocket in 1926. But he kept silent, and his results served hardly anyone but himself.

Oberth published in the right place and at the right time. His book of 1923 created, in Germany, the societies and the vocations from which the first large rockets came.

Tsiolkovsky had himself given the key to this division, without thinking of the other two: first thought and the tale, then calculation, then execution. He occupied, he said, the middle. His sentence on priority settles the rest: it exists today and disappears tomorrow.

Sources: V. N. Sokolsky, in First Steps Toward Space, Smithsonian Annals of Flight no. 10, 1974, pp. 275–276; M. K. Tikhonravov, introduction to Works on Rocket Technology (1947), NASA trans. TT F-243, pp. 6–11; B. N. Vorobyov, in The Call of the Cosmos (1960), pp. 454 and 464–466; A. Zak, russianspaceweb.com; for the Kaluga museum and the lunar crater, the English Wikipedia entries and the Presidential Library of Russia; NASA (Sputnik 1, October 4, 1957; Luna 3, October 1959).