It is important to develop methods for construction in space with local materials, because this reduces the cost of space exploration, provides material for spares and repairs, and makes missions more flexible and effective. The path to crewed Mars expeditions is particularly mass intensive, and a barrier that could be lowered through use of space resources. Structures made from regolith will provide radiation shielding for the crew while working on the Martian surface or Phobos, as well as micrometeoroid shielding for the habitat module, and key thermal insulation. In addition, clayey regolith on asteroids or Phobos can be converted into heat shields for re-entry into Mars' or Earth's atmosphere. Clayey regolith on Mars can be converted into landing pads to enable many-ton, human-tended landers to descend safely. It can be made into pavers or slabs for dust-free work zones on Phobos or Mars, or for roads on Mars, where ISRU operations are occurring. An asteroid can be converted into a Mars Cycler spacecraft by 3D printing with its bulk mass.
DSI is developing end-to-end technology pathways for prospecting, mining, and processing asteroid and other space resources into finished products, primarily to serve in-space markets. Current plans envision HarvestorsTM loaded with NEA resources entering a High Elliptical Earth Orbit (HEEO) with its perigee above geosynchronous orbit where additional processing would be conducted. While HEEO provides good access to geosynchronous orbit, the use of heat shields fabricated from space resources to enable aerobraking down to low Earth orbit would be an efficient alternative to expending significant propellant for the orbit change. Asteroid mining will focus primarily on the iron, nickel, chromium and cobalt that will be utilized for in-space applications. However, delivery to terrestrial markets of by-products such as platinum group metals may become more profitable if entry heat shields are made from asteroid regolith. There are also terrestrial opportunities for this technology. A 3D printing architecture that turns unavoidable clay shrinkage into an asset while drying makes 3D printing with clayey terrestrial regolith a viable technology. This will have commercial application in regions where cement is expensive or not locally available.