NASA - National Aeronautics and Space Administration

NASA is developing a Frisbee-shaped heat shield 16.5 feet (5 meters) in diameter to be attached to the base of the cone-shaped crew module (capsule) of its next, new spaceship, the Crew Exploration Vehicle (CEV.)

The heat shield is a critical item in development of the spaceship. The shield must protect the crew capsule and its precious astronaut crew from temperatures that can melt metal. These ultra-high temperatures result from friction between the air and the speeding spacecraft, which will fly faster than a bullet, returning to Earth through the atmosphere from low Earth-orbit or from the moon.

The effort to develop the heat shield for NASA's new spaceship is moving ahead under the leadership of scientists and engineers at NASA Ames Research Center, located in California's Silicon Valley. Their task is called the CEV Thermal Protection System Advanced Development Project.

To simulate the searing temperatures of the capsule's re-entry into Earth's atmosphere, scientists are using two large NASA 'arc jet' facilities at NASA Ames and NASA Johnson Space Center, Houston. The arc jets can be thought of as room-size blowtorches. They heat air to temperatures that exceed those at the surface of the sun by creating the equivalent of a lightning bolt that runs the length of a long, narrow tube. With a 10- to 60-megawatt electrical arc running through it, the arc jet tube gets so hot that it must be cooled by thousands of water lines.

At the 'business end' of the arc jet tube, a nozzle accelerates and directs superheated air onto sample materials that eventually may be used on the CEV's heat shield. So far, most of the potential heat shield materials only have been tested as small, hockey-puck-sized samples.

	NASA Ames Interaction Heating Facility (IHF) arc jet heater core. + View Larger Image
	Kristina Skokova, arc jet testing principal investigator, with a Teflon calibration 'coupon.' + View Larger Image
	Teflon calibration coupon installation in the NASA Ames aerodynamic heating facility (AHF.) + View Larger Image
	Teflon calibration coupon installation in the NASA Ames aerodynamic heating facility (AHF.) + View Larger Image
	NASA Ames model fabrication and assembly laboratory. + View Larger Image
	Model instrumentation setup in the NASA Ames Interaction Heating Facility (IHF) arc jet. + View Larger Image
	Teflon calibration coupon in the NASA Ames Interaction Heating Facility (IHF) (top view) at 1000 W/cm^2. + View Larger Image
	Arc jet test at the NASA Ames Interaction Heating Facility (IHF) (top view) with thermal protection system (TPS) material coupon glowing after test completion. + View Larger Image
	Thermal protection system (TPS) material coupon undergoing test at 1000 W/cm^2. + View Larger Image
	Thermal protection system (TPS) material coupon undergoing test at 1000 W/cm^2. + View Larger Image
	Thermal protection system (TPS) material coupon undergoing test at 1000 W/cm^2. + View Larger Image

Image Credit: NASA/Ames