Beating the Heat
with Thermal Protection Materials

by Christine E. Johnson

July 6, 2000

I work in the Thermal Protection Materials and Systems Branch at NASA Ames Research Center. I primarily work in two areas - ablator and felt Thermal Protection Systems (TPS). A TPS material protects a spacecraft from the intense heat when it enters another planet's atmosphere or when the spacecraft returns into earth's atmosphere.

Ablator materials can withstand very high heating environments as they dissipate the heat by actually losing some of the material. We have developed very lightweight ablator TPS materials that have been used on recent missions. One material was used on Mars Pathfinder and another is on the Stardust spacecraft, which is currently collecting dust from a comet and will bring it back to earth in 2006. My daily work with these materials includes building test models to test in NASA Ames arc jet test facilities. Arc jet test facilities can simulate the intense heating environment these materials will experience. We test a lot of models to get a sense of how the material will behave and if we need to do some additional development work. There are several upcoming Mars missions in the planning stages, so I support those efforts by helping in designing the TPS for that particular mission and conducting the arc jet tests.

Felt TPS materials are currently used on the Space Shuttle and almost resemble a carpet in some ways. You can roll it out, cut it to shape, and even walk on it. It is lightweight, inexpensive, and easy to maintain. These are all great qualities for a TPS, so we are currently working on developing a felt TPS that can withstand much higher temperatures than the one used on the Space Shuttle. This way, it can be used in a lot more places on the vehicle. We are currently working in the laboratory on small pieces of these materials and will be arc jet testing them soon to see how well they perform.

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