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Poll - First Launch of Falcon9
Poll - First Launch of Falcon9
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Space Station Member ![]() ![]()
Joined: Mon Feb 25, 2008 9:51 am
Posts: 455 Location: Vienna, Austria, Europe, Earth ![]() |
Watching a replay of the launch I just remembered, that there was even another "panic" moment before all that sparkling ice in the plume, that I forgot to mention above: liftoff itself.
I have two questions about liftoff: 1) why did Falcon 9 lift of before T-0? 2) why the roughly 90° roll right at liftoff? Was that because of the interference problems with the FTS? _________________ pride comes before a fall |
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Space Walker ![]() ![]()
Joined: Wed Mar 07, 2007 3:30 am
Posts: 213 Location: USA ![]() |
I can only answer to the first one. I believe that the webcast was out of hawthorn. The sound and countdown graphic were added on top of the live feed. They were added after a separate processing loop causing a disparity. If you watch footage from people on site the lift off is right on time. The engines light 3 second before lift off for the hold down, but lift off happens precisely at T0.
I hope that they get all their coverage issues sorted out for the second flight. Especially being able to handle the huge amount of traffic. They will probably have to set up mirrors all over the continent. |
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Space Station Member ![]() ![]()
Joined: Mon Feb 25, 2008 9:51 am
Posts: 455 Location: Vienna, Austria, Europe, Earth ![]() |
Ah, thanks for the explanation, didn't think about delays between Florida and California + additional processing. (I do know about the hold down of course
![]() Regarding the webcast issues, I hope that Ben from Spacevidcast manages to get in touch with them for some live webcast cooperation. That would be truly awesome! ![]() _________________ pride comes before a fall |
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Space Walker ![]() ![]()
Joined: Sun May 16, 2010 6:36 pm
Posts: 113 ![]() |
Given that second launch will be NASA funded, I'd expect NASATV will cover it.
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Space Walker ![]() ![]()
Joined: Wed Jul 28, 2004 8:30 am
Posts: 236 Location: Perth, Western Australia ![]() |
Went back and had another look at the video and only then noticed the roll at liftoff. Looked quite deliberate and controlled but why? Haven't heard an answer as yet but thought someone mentioned orientation as per initial guidance setup.
Also heard the MECO 2 call but missed MECO 1. Anyone know when the intial 2 main engine shutdown occurred? Cheers. _________________ Beancounter from Downunder |
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Space Walker ![]() ![]()
Joined: Sun Jul 29, 2007 5:18 pm
Posts: 124 Location: UK ![]() |
Maybe the roll at liftoff is the rocket unscrewing itself from the hold-down system?
![]() I guess as an orientation maneouvre to match up with the guidance frame of reference, it looks paticularly peculiar because it is performed so low down, rather than waiting for the rocket to clear the tower (such as it is) before doing it. _________________ We love Google. Google is our friend and protector. |
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Space Station Commander ![]() ![]()
Joined: Wed Aug 18, 2004 8:47 am
Posts: 521 Location: Science Park, Cambridge, UK ![]() |
So why not orient it correctly on the ground so you don't need to do the manoeuvre?
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Space Walker ![]() ![]()
Joined: Sun Jul 29, 2007 5:18 pm
Posts: 124 Location: UK ![]() |
JamesHughes wrote: So why not orient it correctly on the ground so you don't need to do the manoeuvre? Stonking good question. Surely someone at SpaceX can tell us about that roll maneouvre? When you get a minute? _________________ We love Google. Google is our friend and protector. |
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Space Station Member ![]() ![]()
Joined: Mon Feb 25, 2008 9:51 am
Posts: 455 Location: Vienna, Austria, Europe, Earth ![]() |
xiphius wrote: Maybe the roll at liftoff is the rocket unscrewing itself from the hold-down system? ![]() ahahaha, that was a good one, I almost spilled my drink ![]() _________________ pride comes before a fall |
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Space Walker ![]() ![]()
Joined: Sun Apr 30, 2006 10:55 am
Posts: 140 Location: Amsterdam ![]() |
xiphius wrote: Maybe the roll at liftoff is the rocket unscrewing itself from the hold-down system? ![]() ![]() |
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Space Walker ![]() ![]()
Joined: Sun Jul 29, 2007 5:18 pm
Posts: 124 Location: UK ![]() |
JamesHughes wrote: So why not orient it correctly on the ground so you don't need to do the manoeuvre? Maybe the orientation needs to be different for different missions, probably determined by the orbital inclination. The rocket can't be placed on the pad in arbitrary orientations due to the locations of umbilical connections and strongpoints having to match up with things on the pad. So you need to do a mission-specific roll for each launch. _________________ We love Google. Google is our friend and protector. |
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Space Walker ![]() ![]()
Joined: Wed Jul 28, 2004 8:30 am
Posts: 236 Location: Perth, Western Australia ![]() |
No the roll at lift off caught the SpaceX crew by surprise. Turns out it was caused by the rotation of the engine exhaust due to the spiral cooling on the engine exhaust nozzle as well as the turbine roll-control exhaust. Apparently they're going to de-tune this for future flights.
Looked pretty impressive even if unintended when it happened though. This rocket doing a quick roll before she even cleared the tower ![]() _________________ Beancounter from Downunder |
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Space Walker ![]() ![]()
Joined: Sun May 16, 2010 6:36 pm
Posts: 113 ![]() |
Phew... Well it's good it decided to roll along this axis...
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Space Station Member ![]() ![]()
Joined: Mon Nov 29, 2004 1:04 pm
Posts: 257 Location: Norway ![]() |
Mchl wrote: Phew... Well it's good it decided to roll along this axis... ![]() But not as impressive as it would've been if it did it on one of the others, and still managed to complete the objectives! |
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Space Walker ![]() ![]()
Joined: Sun May 16, 2010 6:36 pm
Posts: 113 ![]() |
Haha! That's true!
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