Monday, October 08, 2012

a not perfect flight

There's been some chatter about a "problem" on the SpaceX rocket while going uphill.

It seems that one of the 9 Merlin engines lost power or pressure. The onboard computer(s) immediately shut it down. The telemetry continued which meant the motor was still functional, to a degree. The other motors adjusted automatically and were able to boost the craft into low Earth orbit.

Around the time of the engine shutdown, something happened with the cowling at the base of the rocket. It is visible in slo-mo replays. Clearly something is ripped from the shell and quickly carried away in the supersonic flow. That creeped me out a little. It is not clear if this caused the engine problem or was a result of the engine shutdown.

The net effect of the engine trouble was that a secondary payload, a satellite, was released in an improper orbit. That is disappointing. For all concerned. It was a test satellite. But still...

The impact is not however so severe, happily, that the Dragon cannot make the International Space Station. That mission is not in jeopardy. Good.

Still, I would think this is making some of SpaceX's customers nervous.

Sure, a multi-engine rocket speaks to redundancy and fault-tolerance. But cowling bits flying around at supersonic speeds could end up in places they're not supposed to be.

That the computer avionics compensated for the loss of one motor again reveals some design and contingency forethought. But why could not have achieved the secondary mission? It's a pity they weren't carrying slightly more fuel or that the burn could not have still boosted the payload to an appropriate level.

But then, clearly, it is rocket science.

I do hope however in all the analyses and downstream tests and additional forethought, with NASA's certification, that they will achieve their next big target, carrying humans aloft.

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