The NASA Orion program managers Mark Geyer and Mike Hawes discussed the lessons they learnt from the crew capsule’s first test flight in December 2014 with Space.com, which published the interview on March 29.
The propulsion, guidance and navigation systems had worked well, but the splashdown airbags didn’t, while they also found the heat-shield’s performance could be improved.
The ablative material – dating from the Apollo days – is an epoxy resin called Avcoat that is filled into a fiberglass honeycomb matrix bonded to the rocket’s surface.
According to Geyer and Hawes, the shield is susceptible to cracking under severe swings in temperature. As an alternative, the Orion team plans to make the shield in blocks instead of as a continuous patch. “You make blocks of Avcoat, and there is a seam that you put between these blocks. That will get the strength up,” they’re quoted as saying.
But the more serious concern was with the so-called “stable two”, i.e. upside down, landings of the capsule. This was how the Apollo 7 mission in 1968 splashed down as well, the capsule floating upside down in the water and the astronauts within hanging from the restraining belts on their seats.
A few minutes later, airbags around the capsule would inflate and right it. Hawes said Orion had landed stable-two in 50% of the test-drops. The same thing happened at the end of the December 2014 test-flight. However, the righting mechanism was delayed. It was later found that one of the tanks inflating the airbags was leaking.
Geyer clarified that hanging upside down on Earth after a long time in space would be dangerous for astronauts. When asked if they’d fixed the problem, Hawes said,
We’ve looked at the tanks, the connecting lines and the pyrotechnics. We know that all the valves fired and opened. We know that the tanks all evacuated. We have found in the bags that failed some small cracks in the fabric; it looks like a failure of the fabric itself. Whether that is because of the way they are packaged and come out, we’re not sure, so we are looking at that now.
The duo began – and finished – their interview on a similar refrain: that what they were doing was for their generation, having grown up watching their predecessors perfect the moon-landings.
At the same time, Hawes’s first words in the interview bespoke how their accomplishments weren’t to one-up those of the past but to continue them.
I kind of choked up at the press conference after the flight. I started [my career] when the Apollo guys were still at JSC [Johnson Space Center] and learned from them, and now I finally felt like we had done this for our generation and for the other generations behind us — something we hadn’t done for 40 years … It’s a human spacecraft that’s going much farther than we have gone in a long time.
You can read the full interview here.