spacetoday.net: SpaceX blames Crew dragon accident on faulty valve

Posted: Sat, Jul 20, 2019, 10:23 AM ET (1423 GMT)
SpaceX said Monday that an accident in April that destroyed a Crew Dragon spacecraft during ground tests was caused by a faulty valve. The ongoing investigation into the accident found that nitrogen tetroxide propellant in the vehicle's SuperDraco thruster system leaked through a valve into helium tubes during ground processing. When that system was pressurized just before the planned ignition of the thrusters, a "slug" of oxidizer was hurled against the check valve, shattering and then igniting it. SpaceX said it will replace the check valves in the system with burst disks that won't leak. Neither SpaceX nor NASA provided an updated schedule for upcoming test flights, including vehicle's first crewed mission, but SpaceX said it was "increasingly difficult" to fly that crewed mission this year.