Poll - First Launch of Falcon9

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?

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.

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!

Given that second launch will be NASA funded, I'd expect NASATV will cover it.

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.

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.

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?

ahahaha, that was a good one, I almost spilled my drink

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.

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

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!

Haha! That's true!