ISRU, local resources and first Mars industry
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. ISRU replaces cargo with a process chain
In-situ resource utilisation can reduce launch mass, but oxygen from Mars CO₂ still requires compression, reaction, power, purification, storage and maintenance.
Every kilogram not launched from Earth becomes an industrial obligation on Mars.
Engineering reflex. Identify what is measured, assumed and calculated, then state what would change the decision.
2. MOXIE proved a principle, not a settlement plant
MOXIE demonstrated small-scale oxygen production from the Martian atmosphere under varied conditions. It validated technology, not human-mission propellant capacity.
Scaling from grams per hour to tonnes changes power, compression, thermal control, lifetime and cryogenic storage.
3. Water is a resource only when extraction is defined
Ice may support drinking, oxygen and hydrogen production, but extraction depends on depth, concentration, temperature and surrounding material.
Base-site selection therefore trades landing safety, energy, science and resources.
4. Regolith to materials
Regolith can be sorted, compacted, heated or used as process feedstock, but properties vary and contaminants may require treatment.
Industry begins with characterisation: grain size, mineralogy, volatiles and mechanical behaviour.
5. The first factory must be repairable
A plant that saves cargo but needs one unique Earth-made part every few months does not create durable autonomy.
Performance must track energy per kilogram, availability, purity, maintenance burden and imported dependencies.
6. From resource to product: ISRU is a process chain
Saying that a resource exists in regolith or atmosphere is not enough. It must be acquired, conditioned, fed into a reactor, separated, purified, stored and accompanied by waste handling. Throughput of the complete chain is limited by its slowest step. An ISRU architecture therefore reports efficiency and losses at each stage rather than only the central chemical reaction.
7. Energy is often the real production-rate limit
Excavation, heating, compression, electrolysis and liquefaction consume energy. The operational question is how many useful kilograms are produced per available kilowatt-hour and for how many hours per sol the process can run. During a degraded power mode, ISRU may be a flexible load, but interrupting a furnace or thermal cycle at the wrong point can damage the process. Flexibility has to be designed rather than assumed.
8. Start before the crew: turn production into verified inventory
A robust strategy may operate robotic ISRU before crew arrival and accumulate oxygen, water or propellant. Stored mass is useful only if product quality, tank condition and transfer capability are verified. A crew-departure criterion can therefore depend on measured inventory rather than promised nominal capacity. This turns ISRU from an aspiration into a testable mission condition.
Industrial case: the entire chain must close
An ISRU plant can have an excellent electrolyser and remain unusable if excavation, drying, purification, compression or storage limits throughput. Engineers follow matter and energy from feedstock to stored product. Every step has efficiency, capacity, maintenance downtime and consumables. Overall output is limited by the bottleneck, not by the most spectacular component.
9. Worked example step by step
A unit produces 2.0 kg of oxygen per hour while consuming 5 kW and runs 10 h per sol. Production is 20 kg/sol and energy use is 50 kWh/sol. Over 30 sols without failure it produces 600 kg for 1,500 kWh. If actual availability is 80%, production falls to 480 kg. Sizing therefore separates nominal throughput from operational availability.
10. Progressive exercise
Size a campaign that must accumulate 10 tonnes of oxygen before crew arrival. Choose hourly production, operating hours per sol, availability and storage margin. Calculate required sols and total energy.
11. Reasoned solution
Producing 30 kg of O₂ per day for 300 days yields 9,000 kg. At 18 kWh per kilogram, total energy is 162,000 kWh, or 162 MWh. At 80 percent availability, required power during actual production periods must be higher than a simple division by 365 days suggests; availability and storage therefore belong in sizing.
12. Validation mini-project
Design a complete ISRU chain from feedstock acquisition to storage: equipment, yields, energy, maintenance, quality control, reserves, waste, crew-departure threshold and post-failure strategy.