The engineers also point out that the Mars Observer mission in the 1990's is believed to have been lost to a very similar cause. In that case a backflow valve is believed to have allowed nitrogen tetroxide into helium lines, leading to a rupture of titanium tubing and loss of the vehicle right before it was to perform its Mars orbit insertion burn. So this Crew Dragon problem doesn't appear to be unprecedented.
YazataNov 14, 2019 08:08 AM (This post was last modified: Nov 14, 2019 08:32 AM by Yazata.)
Today November 13, 2019 at Cape Canaveral, SpaceX conducted the same Crew Dragon static fire that went so wrong last time.
This time it seems to have gone well. Assuming that nothing bad is found in all the telemetry data (the capsule was heavily instrumented) and NASA (SpaceX's Commercial Crew customer) is satisfied, the in-flight abort test should take place next month.
In that one they will launch this same Crew Dragon (originally intended to carry the first astronauts, before the last capsule was lost) atop a Falcon 9 with a dummy second stage, and then fire these same rockets right when the Falcon is going through "max Q", maximum aerodynamic pressure, to see if they can separate the capsule from a failing booster at the hardest point. The booster won't be recovered and is expected to fragment from the aerodynamic forces.
Watchers at Cape Canaveral noting that today's static test seemed to have occurred without obvious mishap.
Here's a NASA photo showing Crew Dragon astronauts Bob Behnken (right) and Doug Hurley (left) at SpaceX in Hawthorne California, watching the Crew Dragon static fire take place at Cape Canaveral Florida.
Jul 16, 2019 08:31 AM
![[Image: 800px-Mars_Observer_-_bipropellant_syste...iagram.png]](https://upload.wikimedia.org/wikipedia/commons/thumb/d/d8/Mars_Observer_-_bipropellant_system_failure_diagram.png/800px-Mars_Observer_-_bipropellant_system_failure_diagram.png)
![[Image: EJSWeNzVUAANQ34?format=jpg&name=small]](https://pbs.twimg.com/media/EJSWeNzVUAANQ34?format=jpg&name=small)