<i>"Cause still unknown after several thousand engineering-hours of review. Now parsing data with a hex editor to recover final milliseconds."</i><p>4:09 AM - 29 Jun 2015<p><a href="https://twitter.com/elonmusk/status/615431934345216001" rel="nofollow">https://twitter.com/elonmusk/status/615431934345216001</a>
As a non-native English speaker, I find the omissions of "the" very prominent and interesting in SpaceX speech. "shortly before first stage shutdown", "resulting in loss of mission", "139 seconds into flight", "some period of time following separation", "data to determine root cause" -- is this a general theme in engineering or journalism? I wonder what linguists have to say about this.
"Preliminary analysis suggests the vehicle experienced an overpressure event in the upper stage liquid oxygen tank approximately 139 seconds into flight. Telemetry indicates first stage flight was nominal and that Dragon remained healthy for some period of time following separation."<p>Sounds like they are trying to suggest that if there had been people in the capsule they would have survived...
Just after the pressure event you see Dragon being slung off the rocket... If only it was possible to deploy the parachutes during launch we could've hypothetically saved the payload.<p>I wonder if the launch abort mechanism on the Dragon V2 would've been of any help here too to jettison it safely away from the rocket.<p>I read the rocket was around maximum dynamic pressure during the event (Or just after?) and I'm not sure if it would stand such forces of a jettison during such time.
My thoughts on this. Overpressure in the LOX tank could be due to 1) failure to vent properly or 2) something heating it up.<p>Option 1 is based on the fact that it's constantly evaporating and needs to vent. This seems really unlikely given that it passed all test on the pad 2 minutes before. It also sounds like this was likely ruled out based on Elon's tweet about a "counter intuitive cause".<p>Option 2 sounds like fire or flames due to fuel leakage or something, but then realize that this is the second stage and all the action is going on 100 or more feet down in the first stage. They also have a camera on the 2nd stage engine which was shown shortly before the incident and nothing was going on in there. I wonder what the in-tank camera showed.<p>It seem that to get the extra energy into the tank, something must have fired up early. But if there's one thing Spacex seems to have a lot of it's data. Aside from a breech letting external air in (like the last shuttle accident), how do you get enough added energy into a tank to build pressure to the breaking point? In 2 minutes.