Robotics, autonomy and off-Earth maintenance
Design robots that perceive, plan, manipulate and fail safely when terrain, dust or communications invalidate their assumptions.
Mastery objectives
- explain quantities, units, assumptions and uncertainty
- repeat simple calculations without a black box
- identify interfaces, limits and degraded modes
- turn the result into an operational or architecture decision
1. A robot is a perception–decision–action chain
A planetary robot combines sensing, estimation, planning, control, actuators and supervision. Failure can enter anywhere: a blinded camera, drifting localization, over-optimistic planner, seized joint or ambiguous human command.
Analysis must follow the entire chain. Saying “the arm works” is meaningless if perception cannot localize the part to grasp or software lacks a safe mode when the gripper cannot confirm contact.
2. Perception and localization in sparse terrain
Mars brings dust, hard shadows, relief, lighting changes and no terrestrial GNSS. Robots can combine stereo vision, lidar, inertial sensing, odometry and maps. SLAM—simultaneous localization and mapping—builds or corrects a map while estimating the robot pose.
A map is never the complete world. Autonomy needs confidence measures and must know when to slow down, stop or request supervision because the scene no longer matches its assumptions.
3. Planning: choose a path that remains recoverable
The shortest route is not always best. Mars mobility should include slope, slip, energy, visibility, return margin, thermal exposure and rescue options. A cost function can combine these constraints, but its weights must be explicit.
A logistics robot may rationally choose a longer route if it reduces wheel wear or keeps a recovery path open.
4. Manipulation: grasping is a tolerance problem
A robotic arm needs geometry, force limits, compliance and contact logic. A rigid grasp can damage hardware; a weak grasp can drop it. Dust and temperature also change interfaces used by both robots and suited humans.
Future equipment should be robot-friendly: standardized handles, visual fiducials, tolerant mechanical interfaces, protected connectors and accessible grasp zones.
5. Adjustable autonomy and human–robot teaming
Autonomy can be adjustable. Repetitive well-known work may be delegated; novel conditions can return to human supervision. The system should expose what it believes, what it intends and why it stopped.
The goal is not to eliminate people but to reserve human attention for decisions where judgment adds most value.
6. Multi-robot cooperation and common-cause failure
Several small robots can share mapping, transport and inspection. Cooperation increases capability but adds communications, synchronization and coordination. Three robots running identical software can also share the same defect.
Fleet resilience must therefore distinguish numerical redundancy from real diversity. One bad software update should not immobilize the entire fleet simultaneously.
7. Robotic maintenance and diagnostics
A useful Mars robot should expose wear before failure through motor current, vibration, temperature, mechanical backlash, motion time and position error. Trends support condition-based maintenance.
The machine must also be designed to be repaired: replaceable modules, accessible fasteners, compatible tools, locally manufacturable parts where feasible and a verifiable return-to-service procedure.
8. Worked example: energy autonomy of a robotic sortie
A rover has 8.0 kWh usable. Locomotion averages 600 W while moving and instruments consume 250 W continuously. For a 6 h sortie with 4 h driving, energy is 0.600×4 + 0.250×6 = 2.4 + 1.5 = 3.9 kWh.
If a 30% reserve of capacity must remain untouched, mission energy is limited to 8.0×0.70 = 5.6 kWh. Remaining margin is 5.6 − 3.9 = 1.7 kWh for cold, detours or wheel slip.
Progressive exercise
A four-robot fleet must move 2,400 kg of regolith. Each robot carries 80 kg per trip and one trip takes 25 minutes, but only 75% of scheduled time is productive. Compute the ideal completion time and identify at least three causes that break the independence assumption.
Mini-project
Design an exterior maintenance robot for solar arrays, radiators and antennas: sensors, mobility, arm, autonomy, safing, replaceable modules, health log and task sharing with an astronaut on EVA.