[amsat-bb] Re: Discovery
kd2bd at yahoo.com
Wed Dec 13 11:25:21 PST 2006
--- Nate, WY0X, wrote:
> I'm no expert, just some casual layman's notes below, but did you watch
> the replays on NASA TV, John? Some of what you saw could probably be
> described from the video from the External Tank (ET) centerline camera
> video. (Which is absolutely phenomenal by the way... if you haven't
> seen it and you're reading this, find an outlet for the Flight Day 1
> video and watch the launch videos. The lame press here in the States
> doesn't ever play the good stuff.)
I've seen some external tank videos from previous missions, but didn't get a
chance to see any for STS-116.
> Just after MECO, there's a bunch of thruster, and (I think) OMS engine
> firing to pull away (+Z) from the dropped ET. Plus I would assume the
> main engine bells are probably still quite hot, possibly producing
> visible light? That last part is just a guess.
I did see some smaller flashes some time after the main engines extinguished
(as I was walking back to my car, to be exact), so my guess is that they were
due to OMS firings. I saw some "after glow" for a while as well.
--- Joe Leikhim, K4SAT wrote:
> I would expect the main engines might continue run on for a while because of
> the fuel remaining in the lines and turbo pumps being under tremendous
> pressure and expansion. Also I think the engine bells are cooled by cryo fuel
> so some may remain inside as well and some flow desirable to cool down.
> Perhaps someone more familiar with the engines can describe the shutdown
> process. It is probably more complex than closing one set of valves so that
> unburned fuel doesn't burn/explode when the tank separates.
Sounds like a good question to pose to an astronaut the next time they show up
on 2-meters. :-)
73, de John, KD2BD
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