ISRU timeline
ISRU (In-Situ Resource Utilization) is the idea of 'living off the land'. We use local materials rather than bringing everything from Earth. This page discusses the order in which Martian settlers are likely to start using local resources.
The timeline for In Situ Resources Utilization (ISRU) depends on the type of colonization and missions.
Discussion
The favored type of mission at this time, by SpaceX (Mars One), NASA(ISP ver.5) and the Mars Society(Mars Direct) all rely on ISRU to produce part of the products needed for their operation and success.
The resources and productions planned are listed in the following table by order of development:
| Source | Ressource | Product | ||
|---|---|---|---|---|
| Regolith | Water | Water, CH4, O2 and H2, food*. | ||
| Atmosphere | CO2 | Propellant, Carbon, Oxygen, food. | ||
| Regolith | Regolith | Radiation shielding, roads. | ||
| Atmosphere | Nitrogen | Settlement air, cold thruster gas, food. | ||
| Regolith | To be determined** | Cement, Marscrete, Compressed Regolith Blocks. | ||
| Regolith | Iron Oxyde Fe2O3 | Iron, steel | ||
| Regolith | Calcium Carbonate | Cement | ||
| Regolith | SiO2, Sodium Carbonate | Glass, mirrors, & eventually semi-conductors. | ||
| Basalt | Rock | Construction stone, roads, glass fibres | ||
| Clay | Very fine separated ores | Ceramics | ||
| Salt deposits | Sodium chloride | Salt | ||
| Other Salts | (SO2 4−), (Mg2+), (Ca2+), & (K+) | Chemical precursors |
*Although food will be produced rapidly for experimental and morale purposes, large scale production will probably wait for the colony population to grow substantially before it becomes economical.
**The best construction material made from regolith will be the subject of some of the first materials research done on Mars and an important scientific objective of initial missions.
Why in the above order?
The first Martian missions will likely make return fuel from CO2 from the air. We must bring hydrogen from Earth, unless we are able to use local water (likely in the form of Permafrost).
So the air, and perhaps frozen ground water will be the first items used.
Local materials may be used as radiation protection. The first 'short' Mars missions are likely to just accept the radiation dose of the Mars trip, but bagging up Martian soil (Regolith) and putting sand bags on top of the habitat will lower the radiation dose. Water is a good radiation shield, so using ice in sealed containers could also act as radiation protection. So soil and water are likely to be the next resources used.
Likely longer term colonists will want to grow food. To make soil that plants can live in, we will want Nitrogen. Nitrate deposits have been found on Mars, but likely the first source will be from the air, where N2 is about 2% of the partial pressure.
After this, the order of things become more murky, but using soil for building materials, and starting the processing of dirt and Dust for metals (especially iron), and basic chemicals to start local industries becomes likely next steps.
Examples of ISRU planned for Mars
- We can make StarCrete made out of Martian regolith, starch, & a bit of salt. [1]. Made with potato starch, it is twice as strong as normal concrete.
Also see these two articles: [2], [3]
