LIVE: Space Falcon 9 Flight 2 Static Fire - December 4, 2010

[corrodedNut]

SpaceX main page now reads: : "Static fire successful"

http://www.spacex.com/

[corrodedNut]

SpaceXer: "Picture of all nine Merline engines firing at once during today's static fire test on Launch Complex 40 at the U.S http://twitpic.com/3cv29u "

Nice rez on the still, is it possible that this first camera angle was from an HD camera, and that would explain the lagging and choppiness?

[corrodedNut]

Confirmation on the update page now: http://www.spacex.com/updates.php

[ugordan]

There were white pufs off the interstage vent , 2-3 seconds before T-0 (first attempt).

If there were puffs and not continuous venting then why should it be anything else than a relief valve preventing overpressurization of the tank. There was a short stream of vapor seen on the first launch after liftoff as well.

Second time around, there was none.

Relief valves don't really have to behave deterministically. When and if it will open will obviously depend on tank "heating" rate and (perhaps more importantly) the temperature of RP-1 the LOX tank is sitting on.

Edit: there was voice exchange from test control, right after first abort, with "ox vent" in it.

Of course there was. The first thing that happens after an abort is the tanks depressurize so OX and RP-1 helium vents open.

[ugordan]

SpaceXer: "Picture of all nine Merline engines firing at once during today's static fire test on Launch Complex 40 at the U.S http://twitpic.com/3cv29u "

A bit of white-balancing of that shot:

[zaitcev]

Did you notice in the video that F9 appears to have a "twang" of its own when it ignites? Rocks left and right slightly from that viewpoint.

This video of Soyuz shows it rocking quite a bit at about 0:49
 http://www.youtube.com/watch?v=Su9LkLb5_y4#t=0m43s
(warning - loud)
And mind, Soyuz is held in place by the tail too (not generally visible down in the hole, but the lower supports are there: it's not just the tulip), but Falcon is only attached by its fail. I would expect it rocking even more.
-- Pete

[ugordan]

Interesting video, I must admit I've never seen a Soyuz do that. I wouldn't be surprised if the F9 rocking was caused by the whole launch platform rocking due to the way it's connected/anchored to the ground.

[renclod]

Edit: there was voice exchange from test control, right after first abort, with "ox vent" in it.

Of course there was. The first thing that happens after an abort is the tanks depressurize so OX and RP-1 helium vents open.

Vents open ? Not consistent with "kill ox purge" ... "close ox purge" ... listen from 2:07 in the recording (thanks joshcryer !):

I uploaded the abort sequence:

[butters]

Vents open ? Not consistent with "kill ox purge" ... "close ox purge" ... listen from 2:07 in the recording (thanks joshcryer !):

PROP also called out something like that immediately after the successful fire. On abort, they vent the tank from flight pressure, but then they close the vent when they reach topping pressure so that they don't vent excess LOX in case of recycle. PROP is watching the tank pressure and tells VC when to close the valve.

[Antares]

Vents open ? Not consistent with "kill ox purge" ... "close ox purge" ... listen from 2:07 in the recording (thanks joshcryer !):

Purges have nothing to do with readying a tank for flight.  Purges are for compartments, probably in the case of "ox purge" the inerting of the LOX parts of the engine.

If you look at a Delta II launch, the LOX vent is cycling right up to t-zero.  During terminal count, a tank is brought up to flight pressure with pressurant gas via a new pressure set point.  Then the continuous boil-off exceeds that pressure, so it vents.  This is how every rocket I can think of works.

[renclod]

Vents open ? Not consistent with "kill ox purge" ... "close ox purge" ... listen from 2:07 in the recording (thanks joshcryer !):

Purges have nothing to do with ...

But ... please tell... when is the word "kill" nominally used over the voice loop, in a pad test ?

[ugordan]

Video of the test via The Flame Trench: http://link.brightcove.com/services/player/bcpid51731099001?bctid=697840872001

[ugordan]

But ... please tell... when is the word "kill" nominally used over the voice loop, in a pad test ?

"kill" troubles you, but the numerous "abort" calls during a nominal terminal sequence don't?

[Antares]

Kill == Stop.  Don't read too much into it.  If it's the wrong word, it's just a matter of SpaceX tightening up their comm discipline (which may or may not really be needed).

[robertross]

Well I'm glad they got the static test fire under their belts. Good job.
Now for the launch (and the hard work that goes in between)

[MikeAtkinson]

"kill" troubles you, but the numerous "abort" calls during a nominal terminal sequence don't?

One thing that surprised me was the use of "abort". Firstly as the request to abort the countdown was "abort abort abort" using abort in other contexts could lead to confusion. Secondly it seemed to be used to report an event (something had completed/finished/aborted), rather than as a command (abort the <something> process).

[ugordan]

One thing that surprised me was the use of "abort". Firstly as the request to abort the countdown was "abort abort abort" using abort in other contexts could lead to confusion.

Wasn't it "HOLD! HOLD! HOLD!"? Anyway, I also found the use of "abort" for apparently nominal events surprising, especially since I don't remember hearing them on F9-01. Certainly got my attention more than any "kill" commands.

[Chandonn]

I read the "aborts" (which seemed to mostly center on Dragon systems, btw) as aborting systems during the static fire that would normally be fully functioning during an actual launch.

[ugordan]

That does make sense. I think some FTS call or two also had an "abort" called out.

[R.Simko]

Missed the test fire, I was out running a race.  Glad to here it was successful, congradulations.  Can't wait for Tuesdays launch.