Airbag Backup, Orion designing partial airbags for 'contingency land landing'
Santa Ana, CA - 23 June, 2008
Engineers are developing a relatively lightweight emergency airbag system for NASA's Orion crew exploration vehicle, in case circumstances force it to return to Earth on dry land instead of hitting its nominal target in the ocean off the California coast.
Devising landing modes for the Orion capsule has been a difficult issue for the project, since the weight of the necessary systems eventually must go all the way to the Moon and back. Weight considerations were among the main reasons planners dropped an original requirement last fall that Orion's primary landing mode be on solid ground.
By opting for nominal water recovery near San Clemente Island, northwest of San Diego, planners eliminated 1,000-1,500 lb. from the crew module, says Mark Geyer, the Orion project manager here. But that didn't eliminate the need to be ready for what the project calls "contingency land landing." "You want to protect yourself," Geyer says. "In some cases, in some events, could this vehicle land on land safely?" The answer, it turns out, is yes, at a weight penalty of only 300-400 lb.
Orion engineers are at work on a concept that would put foul' cylindrical airbags behind two doors on the "toe" of the Orion capsule to wrap around and cushion it as it touches down at an angle on dry land.
If winds pull the capsule across the landing site so it will hit at an angle to the surface, the Orion reaction control system lines it up so the airbag system at the crew's feet is facing downward on impact, Geyer says. The landing would be rough, but engineers believe the crew would survive.
"In most cases I can hit water if I want to, so it's not a very high probability case," Geyer says. "But you didn't want to be at the point where you say 'I can never do it; if I hit the land these guys are not going to make it.'" The system also may ease impact with the water if one of the three giant parachutes that will slow the capsule after re-entry should fail, and in other off-nominal water-landing cases, he says.