Radiation, dosimetry and crew protection
This course develops a capability that was still missing from the core curriculum. It starts from concepts and units, builds the necessary calculations, then connects each method to real Mars engineering decisions.
Mastery objectives
- explain quantities, units and assumptions
- repeat at least one calculation by hand
- identify uncertainty, limits and failure modes
- turn the result into a decision for a Mars architecture
1. Chronic galactic radiation and solar events
Galactic cosmic rays create a persistent background while solar particle events can rise rapidly. A mission must manage cumulative exposure and short-term shelter response.
Shielding is not a perfect wall because energetic particles can generate secondaries.
Engineering reflex. Identify what is measured, assumed and calculated, then state what would change the decision.
2. Absorbed and equivalent dose
Absorbed dose is measured in gray, Gy, or joules per kilogram. Equivalent/effective dose uses sievert, Sv, to account for biological effect.
The units are not interchangeable and every technical page must state which quantity it uses.
Engineering reflex. Identify what is measured, assumed and calculated, then state what would change the decision.
3. Shielding geometry
A compact storm shelter surrounded by water, food or other hydrogen-rich stores can be more efficient than adding the same mass everywhere.
Radiation protection is partly an architecture and storage problem.
Engineering reflex. Identify what is measured, assumed and calculated, then state what would change the decision.
4. Personal and area dosimetry
Crews need cumulative personal dose records while habitats, rovers and EVA paths need mapped exposure.
Operational decisions connect solar forecasts, dosimeters, shelter location and the time required to stop work.
Engineering reflex. Identify what is measured, assumed and calculated, then state what would change the decision.
5. Settlement protection
Long-term settlements can use geometry, hydrogen-rich materials and possibly regolith, but burying structures creates access and maintenance problems.
The best solution reduces radiation risk without making other hazards unmanageable.
Engineering reflex. Identify what is measured, assumed and calculated, then state what would change the decision.
Worked example step by step
Build a nominal case and a degraded variant. Write every input with units, convert to one coherent system, perform the calculation, then translate the result into a sentence. Finally vary the most uncertain parameter by ±20% and check whether the decision changes.
Progressive exercise
- Choose a Mars subsystem and list five inputs.
- Classify each input: measured, sourced, assumed or calculated.
- Calculate the nominal case.
- Inject uncertainty or a failure.
- Decide: continue, degrade, stop or reconfigure.
Reasoned solution
A good solution shows units, reasoning, sensitivity and the decision. A numerical result without physical interpretation is not a complete solution.
Validation mini-project
Produce a three-to-five-page engineering note with need, assumptions, diagram, calculation, uncertainty, injected failure, decision criterion and at least three primary sources.