National Aeronautics and Space Administration

The Challenge

• High-mass planetary surface access is one of NASA’s technical challenges. A Solution • Entry into an atmosphere creates large amounts of frictional heat on • Create ISRU (In Situ Resource the vehicle. Utilization) heat shields in-situ or on-site at the planetary destination • A heat shield is a large and heavy from the regolith. component of a descent vehicle. • Three possible methods: • The cost to put a payload on the  Sintering or partial melting of surface of Mars is around $200,000 the regolith. per pound or $440,000 per kilogram.  High temperature polymer binding • A mission to Mars would require heat agent mixed in the regolith. shields on the order of 20 meters in diameter, which would weigh tons  Use molten by-product of ISRU and could not fit into existing oxygen extraction from regolith to rocket shrouds. mold heat shields.

Dr. Michael Hogue Electrostatics and Surface Physics Laboratory michael.d.hogue@nasa.gov • (321) 867-7549 www.nasa.gov SP-2017-01-003-KSC Regolith-Derived Heat Shield

High-mass planetary surface access is one of NASA’s technical challenges involving entry, descent and landing (EDL). During entry and descent, frictional interaction with the planetary atmosphere causes heat to build up on the spacecraft’s surface, which will rapidly destroy it if a heat shield is not used. However, heat shields have high mass, making them expensive to launch from Earth, around $10,000 per pound just to low-Earth orbit.

A new mass-efficient and innovative Arc jet test of a regolith derived heat shield specimen. concept for heat shields is to make them from local materials at or near the kilometers per second. destination with in situ resource utilization, In addition to human return, it is very or ISRU. Regolith – the loose rocky layer likely that private companies will want to of material on planets, asteroids and return cargo to Earth. Platinum, titanium, moons – has the insulating properties and helium-3, and other metals and minerals high temperature resistance desirable for are all high-value commodities in limited a heat shield. Many space missions are supply. It may be profitable to mine these one-way trips to place an asset in space throughout the solar system and return for economic or scientific purposes. But them to Earth if an economical method for human missions, a reliable heat shield is found. is even more important to protect the crew from intense heat created during If the heat shield could be manufactured high-entry velocities (around 11 kilometers in space, it could be outfitted on a per second). For human missions to Mars, spacecraft prior to atmosphere entry, the return is even more difficult, with Earth thereby achieving significant propellant atmosphere entry velocities up to 14 and mass savings during launch and space operations.