SpaceX Falcon 9 v1.1 - SES-8 - DISCUSSION THREAD

[QuantumG]

Yeah, let's not get into a smug fight. It's 5:40am here, England are doing crap in the Ashes (Quantum will be happy)

Actually, the guy handing out free booze at the bottle shop wouldn't shut up about it.. or give me any of his free booze.

[woods170]

  But we had engineers on that thread saying "That's not good!" (by reaction). So I don't think it was the magic LOX fairies at work - clearly something was off nominal.

Quick question here: were any of those engineers actually working for SpaceX?

[mlindner]

  But we had engineers on that thread saying "That's not good!" (by reaction). So I don't think it was the magic LOX fairies at work - clearly something was off nominal.

Quick question here: were any of those engineers actually working for SpaceX?

Someone can slap me if I'm wrong but. From my understanding there were no SpaceX engineers commenting here on the public thread, unless someone is hiding what they really do. We had several engineers/technicians commenting though who have dealt with rocket vehicles though and that was all Chris was meaning.

[hrissan]

Apparently the insurers of SES-8 are also content with the explanation from SpaceX. See screenshot below:

And apparently not the fuel lines were frozen by O2 exposure, but the igniter-fluid lines.

Exactly. So the "cold start" means actually lack of ignition and subsequent shutdown.

[sweet-d]

Well I guess it's good to know that they found and fixed the problem with 2nd stage re ignition.

[ugordan]

Well I guess it's good to know that they found and fixed the problem with 2nd stage re ignition.

If experiences from the past (for example AC-70 and AC-71, Taurus OCO and Glory launches) are any indication, we will know they found and fixed the problem only after the 2nd stage actually reignites.

Also, this is now the 2nd time freezing has been an issue on the MVac due to GOX impingement. Hmm.

[IRobot]

Will insulation be enough or will they need some active heaters?

[Lar]

If experiences from the past (for example AC-70 and AC-71, Taurus OCO and Glory launches) are any indication, we will know they found and fixed the problem only after the 2nd stage actually reignites.

Also, this is now the 2nd time freezing has been an issue on the MVac due to GOX impingement. Hmm.

Yes, the proof is in the pudding, although one can hope they sorted it... active heating will be harder.  Can you remind us which mission the first freezing issue was on?

[ugordan]

Can you remind us which mission the first freezing issue was on?

Maiden F9 launch. Roll control nozzle froze.

Could also have had something to do with that restart issue, as well, but that's speculation on my part.

[Lars_J]

I saw this image in the update thread - It gives a nice view of the umbilical connections:

EDIT: I added a v1.0 T/E shot from a similar angle as a comparison.

[Lurker Steve]

So it that crane a normal part of SpaceX operational flow now ?
We've seen it for both F9 V1.1 flights now.
 

[Lars_J]

So it that crane a normal part of SpaceX operational flow now ?
We've seen it for both F9 V1.1 flights now.
 

I doubt it. Both v1.1 flights are now from modified pads with new transport/erector. Although they have used similar cranes when inspecting the upper stage while on the pad.

As for "that crane", I'm sure they just rent a crane as needed.

[russianhalo117]

So it that crane a normal part of SpaceX operational flow now ?
We've seen it for both F9 V1.1 flights now.
 

I doubt it. Both v1.1 flights are now from modified pads with new transport/erector. Although they have used similar cranes when inspecting the upper stage while on the pad.

As for "that crane", I'm sure they just rent a crane as needed.

The crane Co's  website is www.beyel.com Name on crane is BEYEL. There website's project section has Space all over it. Stretching from Titan to Shuttle to NASA construction projects. Space related projects are mainly what they have done since the Atlas days to present.

[Comga]

So it that crane a normal part of SpaceX operational flow now ?
We've seen it for both F9 V1.1 flights now.

What is the crane doing in this photo?
It doesn't look like it helped to stand up the rocket as the crane seemed to do at VAFB.
Is that a technician in a cage?
Is this a practice for astronaut ingress/egress from DragonRider? 

[Comga]

Can you remind us which mission the first freezing issue was on?

Maiden F9 launch. Roll control nozzle froze.
Could also have had something to do with that restart issue, as well, but that's speculation on my part.

Also on the maiden F9 flight there were the tears in the second stage engine bell, which then had to be shortened. 
It was my (quite non-authoritative) conclusion that these could have been caused by cold LOX boil-off impinging on the thin Niobium.  That would generate localized tension which could have been relieved by cracking.

[ugordan]

Also on the maiden F9 flight there were the tears in the second stage engine bell, which then had to be shortened. 

No, it was on the COTS C1 launch and the concensus was, I think, either a GN2 or He vent somewhere in the interstage that caused it.

[cambrianera]

Yes, COTS Flight 1; GN2 vent causing fluttering (ie vibration then fatigue cracking).
http://www.spaceref.com/news/viewpr.html?pid=32213

[Lars_J]

Some Elon tweets today about the launch:

https://twitter.com/elonmusk/status/404059376652005377

Elon Musk ‏@elonmusk
Headed to Cape Canaveral tomorrow for first @SpaceX geostationary satellite launch.

https://twitter.com/elonmusk/status/404063199227437057

Elon Musk ‏@elonmusk
Will be toughest mission to date. Requires coast + upper stage restart + going to 80,000 km altitude (~1/4 way to moon).

https://twitter.com/elonmusk/status/404073926247972864

Elon Musk ‏@elonmusk
Launch can be viewed live from Cape causeways or via http://SpaceX.com  webcast around 5:30 local time on Monday.

EDIT: StarryKnight made a great post about the mission and GTO choice here: http://forum.nasaspaceflight.com/index.php?topic=32990.msg1105331#msg1105331

[Jason1701]

Would it be possible to inject the satellite into the super-synchronous transfer orbit with just one burn of the second stage?

[sdsds]

Would it be possible to inject the satellite into the super-synchronous transfer orbit with just one burn of the second stage?

One burn of the second stage pretty much leaves you in an orbit inclined no less than the latitude of the launch site. I'm assuming like other GTO launches from the Cape, Falcon 9 will attempt to perform the second burn somewhere near the equator? Isn't that the scenario where inclination can be reduced most efficiently?

(So yes, one burn would be enough to reach some super-synchronous orbit. Would that orbit qualify as a geostationary transfer orbit, though?)

EDIT to add link to an expert view: http://forum.nasaspaceflight.com/index.php?topic=32990.msg1105331#msg1105331