SpaceX Pinpoints Crew Dragon Abort System Flaw

摘要

Check valves normally allow fluids to flow through in only one direction, so it came as a surprise to SpaceX to learn that a slug of liquid oxidizer made it through a valve in a Crew Dragon capsule's helium pressurization system, triggering an explosion that destroyed the test capsule and delaying a key crew flight test to the International Space Station (ISS).NASA is counting on SpaceX and Boeing to begin crew ferry flights to the ISS as soon as possible, though program managers caution that safety trumps schedule when it comes to flying astronauts. Both companies have had technical issues with their spacecraft's escape systems, intended to fly a crew to safety in case the launch vehicle fails during ascent. During a June 2, 2018, hot-fire test in White Sands, New Mexico, four of eight valves in the propellant system of Boeing's CST-100 Starliner abort engines, made by Aerojet Rocketdyne, failed to close properly, triggering a leak of hy-pergolic propellants.