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Post by ka9q on Jul 18, 2010 16:43:08 GMT -4
That's what Space-X said, but I still have my doubts. Immediately after staging, the second stage seemed pretty stable. The attitude oscillations built up only later.
At staging, the upper stage tanks are full so there should be little opportunity for the propellants to slosh. That can only happen later as an ullage forms.
So while I can certainly believe that the loss of the mission was caused by sloshing of the upper stage propellants that couldn't be controlled by the flight control system, I find it hard to understand how that was caused by the recontact during staging. They seemed to be two separate phenomena.
Although the upper stage nozzle hit pretty hard - it even looked like it had bent elastically - it seemed undamaged and appeared to operate normally until the end of the video.
I would have thought baffles in propellant tanks are more or less mandatory. It's far easier to just add the baffles than to figure out how to dampen sloshing in software, although they do admittedly add some weight. Baffles also prevent swirling of the propellants, which can add so much roll momentum to the launcher that it could conceivably run out of roll control authority. I noticed the Falcon 1 rolling quite a bit toward the end of its flight.
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