[meteorite-list] NASA Selects Material for Orion Spacecraft Heat Shield

[Ron Baalke]

April 7, 2009

Ashley Edwards/Grey Hautaluoma 
Headquarters, Washington 
202-358-1756/0668 
ashley.edwards-1 at nasa.gov, grey.hautaluoma-1 at nasa.gov 

Kylie Clem 
Johnson Space Center, Houston 
281-483-5111 
kylie.s.clem at nasa.gov 

RELEASE: 09-080

NASA SELECTS MATERIAL FOR ORION SPACECRAFT HEAT SHIELD

HOUSTON -- NASA has chosen the material for a heat shield that will 
protect a new generation of space explorers when they return from the 
moon. After extensive study, NASA has selected the Avcoat ablator 
system for the Orion crew module. 

Orion is part of the Constellation Program that is developing the 
country's next-generation spacecraft system for human exploration of 
the moon and further destinations in the solar system. The Orion crew 
module, which will launch atop an Ares I rocket, is targeted to begin 
carrying astronauts to the International Space Station in 2015 and to 
the moon in 2020. 

Orion will face extreme conditions during its voyage to the moon and 
on the journey home. On the blistering return through Earth's 
atmosphere, the module will encounter temperatures as high as 5,000 
degrees Fahrenheit. Heating rates may be up to five times more 
extreme than rates for missions returning from the International 
Space Station. Orion's heat shield, the dish-shaped thermal 
protection system at the base of the spacecraft, will endure the most 
heat and will erode, or "ablate," in a controlled fashion, 
transporting heat away from the crew module during its descent 
through the atmosphere. 

To protect the spacecraft and its crew from such severe conditions, 
the Orion Project Office at NASA's Johnson Space Center in Houston 
identified a team to develop the thermal protection system, or TPS, 
heat shield. For more than three years, NASA's Orion Thermal 
Protection System Advanced Development Project considered eight 
different candidate materials, including the two final candidates, 
Avcoat and Phenolic Impregnated Carbon Ablator, or PICA, both of 
which have proven successful in previous space missions. 

Avcoat was used for the Apollo capsule heat shield and on select 
regions of the space shuttle orbiter in its earliest flights. It was 
put back into production for the study. It is made of silica fibers 
with an epoxy-novalic resin filled in a fiberglass-phenolic honeycomb 
and is manufactured directly onto the heat shield substructure and 
attached as a unit to the crew module during spacecraft assembly. 
PICA, which is manufactured in blocks and attached to the vehicle 
after fabrication, was used on Stardust, NASA's first robotic space 
mission dedicated solely to exploring a comet, and the first sample 
return mission since Apollo. 

"NASA made a significant technology development effort, conducted 
thousands of tests, and tapped into the facilities, talents and 
resources across the agency to understand how these materials would 
perform on Orion's five-meter wide heat shield," said James Reuther, 
the project manager of the study at NASA's Ames Research Center at 
Moffett Field, Calif. "We manufactured full-scale demonstrations to 
prove they could be efficiently and reliably produced for Orion." 

Ames led the study in cooperation with experts from across the agency. 
Engineers performed rigorous thermal, structural and environmental 
testing on both candidate materials. The team then compared the 
materials based on mass, thermal and structural performance, life 
cycle costs, manufacturability, reliability and certification 
challenges. NASA, working with Orion prime contractor Lockheed 
Martin, recommended Avcoat as the more robust, reliable and mature 
system. 

"The biggest challenge with Avcoat has been reviving the technology to 
manufacture the material such that its performance is similar to what 
was demonstrated during the Apollo missions," said John Kowal, 
Orion's thermal protection system manager at Johnson. "Once that had 
been accomplished, the system evaluations clearly indicated that 
Avcoat was the preferred system." 

In partnership with the material subcontractor, Textron Defense 
Systems of Wilmington, Mass., Lockheed Martin will continue 
development of the material for Orion. While Avcoat was selected as 
the better of the two candidates, more research is needed to 
integrate it completely into Orion's design. 

For more information about the Orion crew module, visit: 

http://www.nasa.gov/orion 

For more information about the Constellation Program, visit: 

http://www.nasa.gov/constellation 
	
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