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

[Zaran]

To move my question here from the update thread (sorry!):

[In relation to the WDR+HF test]If it was a tank rupture, would you expect it to vent that heavily for as long as it has been?

Looked to me, not that I have any in depth knowledge of the systems in place here, that the plume was originating near were I believe the umbilical are connected to the first stage, might be a bad connection there perhaps?

[Comga]

It didn't look good on the video before they cut it off.
People have speculated about a rupture, but Jim assures us that it doesn't look like liquid coming out of the first stage.  Could be GSE.  Could be venting the whole LOX load. 
Second stage venting looks normal, Jim says.

[Elvis in Space]

To move my question here from the update thread (sorry!):

[In relation to the WDR+HF test]If it was a tank rupture, would you expect it to vent that heavily for as long as it has been?

Looked to me, not that I have any in depth knowledge of the systems in place here, that the plume was originating near were I believe the umbilical are connected to the first stage, might be a bad connection there perhaps?

Yeah who knows? Light rain, ice buildup somewhere on a valve or umbilical connection? I would think if it was on the T/E then they would have been able to shut off the flow.

[rcoppola]

Ok, to me it seemed there was a rupture in the umbilical connection and they couldn't turn off the pumps. Is that even feasible?

[Lars_J]

To move my question here from the update thread (sorry!):

[In relation to the WDR+HF test]If it was a tank rupture, would you expect it to vent that heavily for as long as it has been?

Looked to me, not that I have any in depth knowledge of the systems in place here, that the plume was originating near were I believe the umbilical are connected to the first stage, might be a bad connection there perhaps?

A tank rupture is probably unlikely. The S1 LOX tank remained iced over, and it was venting for a while. It is hard to tell, but the venting could have come from the S2 lines in the T/E.

BTW, the S1 is filled from the bottom. There is no connector where the vent smoke ended.

[Oberon_Command]

Is it possible that the tanking went well, then the hotfire occurred as planned, but something in the GSE failed preventing them from draining the LOX back, necessitating just venting all the LOX in the tank? If that were the case, would the stage take any damage from venting all the lox?

[ugordan]

People have speculated about a rupture, but Jim assures us that it doesn't look like liquid coming out of the first stage. 

I'm not so sure about that. If the leak was small and high up, LOX could have trickled down the stage while evaporating vigorously. At the end, before they cut off the feed, the venting was coming off even from below the LOX tank suggesting that it was spilling along the tank spin, to the RP-1 tank.

Wathing it on a recording, the weird thing is the venting didn't seem to start abruptly at all.

[Bugfix]

Is it possible that the tanking went well, then the hotfire occurred as planned, but something in the GSE failed preventing them from draining the LOX back, necessitating just venting all the LOX in the tank? If that were the case, would the stage take any damage from venting all the lox?

Well, it was already heavyly venting before the scheduled time of the hotfire, so this seems unlikely.

[Zaran]

BTW, the S1 is filled from the bottom. There is no connector where the vent smoke ended.

Ah, I didn't know this! Thanks for that info, guess that means the TE is the primary suspect here.

[WHAP]

Moved from update thread:

Anyone know whether S-X fills their tank from the bottom or the top?  I'd think the bottom, but I don't know.  If it's the bottom, I wouldn't expect a GSE problem with the first stage fill mechanism to result in a plume that looks like what we saw - more something coming from the top or side.

Another option could be a problem with the fill line for S2, but it just didn't seem like that to me.

[rcoppola]

It felt like an overflow issue. Like they couldn't turn the pumps off and the bucket just started overflowing.

[Lars_J]

Moved from update thread:

Anyone know whether S-X fills their tank from the bottom or the top?  I'd think the bottom, but I don't know.  If it's the bottom, I wouldn't expect a GSE problem with the first stage fill mechanism to result in a plume that looks like what we saw - more something coming from the top or side.

Another option could be a problem with the fill line for S2, but it just didn't seem like that to me.

The connections can be seen in this image. Stage one is filled from the bottom/base.

[sdsds]

Can anyone find any previously released imagery showing the S1 LOX vent hardware? Assuming a large enough rupture unplanned opening near there, could boiling LOX in the tank "splash" out and dribble down the outside of the tank before evaporating off? Would that explain what we observed?

[WHAP]

Ok, to me it seemed there was a rupture in the umbilical connection and they couldn't turn off the pumps. Is that even feasible?

Yes, if you've only got one set of valves between the pumps (if any - many vehicles do not use pumps) and the tank.  Usually should have at least two in between.

[edkyle99]

It didn't look good on the video before they cut it off.

I'm clearing my throat, but there doesn't seem to be a thread for that. 
http://forum.nasaspaceflight.com/index.php?topic=33182.0

 - Ed Kyle

[Jim]

BTW, the S1 is filled from the bottom.

SOP for first stages

[rcoppola]

It didn't look good on the video before they cut it off.

I'm clearing my throat, but there doesn't seem to be a thread for that. 
http://forum.nasaspaceflight.com/index.php?topic=33182.0

 - Ed Kyle

Point taken.

[ugordan]

Can anyone find any previously released imagery showing the S1 LOX vent hardware? Assuming a large enough rupture unplanned opening near there, could boiling LOX in the tank "splash" out and dribble down the outside of the tank before evaporating off?

It might, IMHO.

[mheney]

Along with the significant venting along the 1st stage LOX tank, there was a lesser (but still notable) amount of venting from the 2nd stage LOX tank - there was a "crown" of vapor over the stack.  May be wishful thinking - but that sounds more like a GSE issue than a vehicle issue - two leaky stages seems less likely...

[Chris Bergin]

GSE would make more sense as they have been working on that until the last minute.