nacnud - 21/3/2007 2:30 AMThe staging is at T+2:52 and the oscillations aren't redialy apparent until T+4:30. That's a fair time difference
Chris Bergin - 20/3/2007 7:42 PM I should say, before we write up some post launch article from Elon quotes, that I think what we've just seen is astonishing. Well done SpaceX.
Indeed, a great achievement.
Danderman - 20/3/2007 10:39 PMQuoteJonSBerndt - 20/3/2007 7:36 PM Question: What is the arrangement of the ullage motors on Falcon - assuming they have them to settle the fuel prior to second stage ignition? It seems as if there is something forcing a rate on the upper stage prior to ignition.Or, am I imagining things? Any estimates on qbar? Altitude and velocity at staging? Jon I was not aware that pressure fed engines require ullage motors.
JonSBerndt - 20/3/2007 7:36 PM Question: What is the arrangement of the ullage motors on Falcon - assuming they have them to settle the fuel prior to second stage ignition? It seems as if there is something forcing a rate on the upper stage prior to ignition.Or, am I imagining things? Any estimates on qbar? Altitude and velocity at staging? Jon
I was not aware that pressure fed engines require ullage motors.
Chris Bergin - 20/3/2007 7:43 PM And it's the last 15 seconds where the view of the Earth really starts to wander (roll problem).
Although it did not seem like a very serious roll problem - in fact, if that were the only problem, it would be a non-problem, since a little roll is not a bad thing. However, I noticed that after 4 minutes, when the oscillations began, the launch crew became very tight lipped.
On the other hand, the circular oscillations were worrisome.
daveglo - 21/3/2007 2:40 AMI'll throw my $0.02 in with the other folks offering congratulations to SpaceX. Take the partial success, and build on it. So it wasn't perfect. So what? It's still a bargain, even if it was sub-orbital. 300KM is nothing to sneeze at. And thanks to Chris and the others for the L2 video, best turnaround time on the web!
yinzer - 20/3/2007 7:50 PM Severe pogo could cause the loss of telemetry easily - high amplitude vibrations will lead to structural failure, and could easily knock the batteries powering the stage loose.
Well, that is certainly true, but when I wrote "severe pogo" I was not thinking of "tear the vehicle apart" pogo.
But let me ask the crew here: what failure modes WOULD cause the telemetry to cease? Discounting, of course, coincidental telemetry or electrical problems.
Eeyore3061 - 20/3/2007 8:46 PMQuoteDanderman - 20/3/2007 10:39 PMI was not aware that pressure fed engines require ullage motors. Yes, to keep them from swallowing a bubble of pressurant. ... and possably locking up the lines Michael.
Danderman - 20/3/2007 10:39 PMI was not aware that pressure fed engines require ullage motors.
marsavian - 20/3/2007 8:46 PMa bold quote 'He doesn't foresee needing another test flight before launching the first operational mission in late summer carrying the U.S. military's TacSat 1 spacecraft.'http://www.space.com/missionlaunches/sfn_070320_spacex_falc1cntdwn.html
'He doesn't foresee needing another test flight before launching the first operational mission in late summer carrying the U.S. military's TacSat 1 spacecraft.'
http://www.space.com/missionlaunches/sfn_070320_spacex_falc1cntdwn.html
Well at least he's consistently in character. You have to be a bit arrogant to lead a bunch of scientists, engineers, techs, and associated riffraff :-). He's also demonstrated that he can and does learn. Oh, to be a fly on the wall tomorrow back in El Segundo...
Next up is more learning curve: Bring on the various government inspectors associated with launching a US asset.
DCMA, anyone?
Danderman - 20/3/2007 8:53 PMBut let me ask the crew here: what failure modes WOULD cause the telemetry to cease? Discounting, of course, coincidental telemetry or electrical problems.
Eeyore3061 - 20/3/2007 9:46 PMQuoteDanderman - 20/3/2007 10:39 PMQuoteJonSBerndt - 20/3/2007 7:36 PM Question: What is the arrangement of the ullage motors on Falcon - assuming they have them to settle the fuel prior to second stage ignition? It seems as if there is something forcing a rate on the upper stage prior to ignition.Or, am I imagining things? Any estimates on qbar? Altitude and velocity at staging? Jon I was not aware that pressure fed engines require ullage motors.Yes, to keep them from swallowing a bubble of pressurant. ... and possably locking up the lines Michael.
Stargazin2nite - 20/3/2007 10:12 PMDanderman -- good point -- I just checked the payload in more detail and it does look like instrumentation to characterize the launch. At first I was under the impression that DARPA was adding an additional functional satellite, but that appears not to be the case.In any event, I am still amazed that a company with only 250 people have accomplished this!
