Prototype heat shield for NASA Orion capsule arrives at Kennedy

William Atkins
Friday, 29 February 2008 20:52

Science - Space

The heat shield that will protect the new Orion space capsules as it sends astronauts back and forth between Earth and the Space Station, and later between Earth and the Moon, Mars, and other places, has arrived at the NASA Kennedy Space Center for testing.             

Based on technologies from the space shuttle and Apollo, the new crew exploration vehicle (CEV) aft heat shield for the Orion space capsule is one of the first pieces to be developed for NASA’s new Project Constellation.

The heat shield is called a manufacturing demonstration unit (MDU), which means it is not hardware that will go out into space, but only a full-scale test hardware that will simulate how the real shield will look and work.

The MDU prototype was built so that it could be evaluated, tested, inspected, and handled so revisions and improvements could be made before the final shield is manufactured and eventually used for space missions.

The heat shield will be tested for several months in Hanger N at the Cape Canaveral Air Force Station. Laser and x-ray scans, along with other tests, will be used to evaluate the shield in what is called tests of nondestructive evaluation (NDE).

The diameter of the heat shield is 16.5 feet (five meters). The heat shield for Orion will contain similar tile materials from the shuttle’s thermal protection system (TPS). The tiles will form the inside base of the heat shield.

The outside part of the heat shield, the part that will endure the most heat during re-entry into Earth’s atmosphere, will be ablative materials similar to what was used during the Apollo Program. The ablative material is called phenolic impregnated carbon ablator (PICA).

The heat shield will use about 200 pieces of the PICA material. The ablative materials will burn away, or “ablate,” as the capsule descends through the atmosphere at over 25,000 miles (40,000 kilometers) per hour and at temperatures as high as 5,000 degrees Fahrenheit (2760 degrees Celsius) when returning from missions to the Moon, Mars, and other longer space voyages.

The PICA material protects the space shuttle more efficiently than the shuttle’s TPS tiles, which is why they are used on the outer section of the heat shield, where the heat will be more intense. The two layers will be bonded together using materials from the space shuttle program.

Why was the PICA material used for the new Orion space capsules? Read on for the answer!