I know what you’re thinking, and no, that’s not a UFO in a secret government laboratory. It’s not a prop for an upcoming science fiction movie, and it’s not the world’s largest Frisbee. It’s a prototype heat shield, developed by Boeing for NASA’s Orion Crew Exploration Vehicle.
When Orion returns from space, it needs to decelerate from orbital velocity to be able to land safely. Just like the space shuttle, the capsule will point this heat ablating surface into the atmosphere, and let it get super hot. The heat shield can rise to extremely high temperatures, while the astronauts stay nice and safe.
The lunar protective system will need to be much more capable that the shuttle’s system, since capsules will be returning directly to the Earth after flying from the Moon. In some cases, Orion’s thermal protection will face 5 times as much heat as vehicles returning from the International Space Station. That’s hot.
It was the catastrophic failure of Columbia’s heat shield that doomed it when it was re-entering the Earth’s atmosphere. Needless to say, NASA wants to get this right.
The contract for the new Thermal Protection System was awarded to Boeing Advanced Systems about a year ago. Last month, a NASA Ames technical and quality inspection team completed an acceptance review of the shield.
The shield is made from Phenolic Impregnated Carbon Ablator (PICA). That’s a mouthful, but it uses a special trick to keep the capsule cool. As the heat shield heats up during reentry, the PICA material “ablates”. It chars, melts and then sublimates to create a cool boundary layer that protects the spacecraft.
Boeing will continue working on the heat shield, to meet Orion’s TPS preliminary design review in early 2008.
Original Source: Boeing News Release