SpaceX Falcon 9 : GPS III SV01 : SLC-40 : Dec. 23, 2018 - DISCUSSION

[ugordan]

A fan dedicated enough to do the analysis could probably derive some data by looking at the history of all the scrubs, the mission characteristics, and what the upper level winds actually were (if that's available data). Interesting to see if there were trends there.

I'm really skeptical about that given the very few data points we have on high level winds scrubs, especially for a Block 5 which has a notably different trajectory profile from previous blocks. The fact this fairing carries extra TPS on top is yet another question mark about what kind of flight profile this mission is supposed to fly.

I thought it was my dodgy cable company but I noticed it too, the auto resolution selection wanted to do 140 or some small number like that....

See my point directly above, seems to be a Youtube "feature"...

[kessdawg]

Wow, I thought crappy quality was because I was casting to my TV instead of watching on my monitor.  Boo.

[rickl]

Interesting that they took the count to T-0:29 even after calling an abort for winds. Must have wanted to test out the out of family sensor fix to make sure it was really fixed.

That's what I thought, too.  I've never heard of continuing a count after calling a scrub.  Someone more knowledgable than me can probably provide examples.

I was frankly surprised that they went ahead with fueling after pushing T-0 to the end of the window.  I was expecting a replay of Thursday.  When the webcast started, I was worried that they would try to launch too close to the limit.

[Wolfram66]

Is there a website that forecasts upper level winds?

Here: https://www.patrick.af.mil/Portals/14/documents/Weather/L-1%20Forecast%2022%20Dec%20Launch.pdf?ver=2018-12-21-082828-370

This is what the soundings returned...

[DigitalMan]

Interesting that they took the count to T-0:29 even after calling an abort for winds. Must have wanted to test out the out of family sensor fix to make sure it was really fixed.

That's what I thought, too.  I've never heard of continuing a count after calling a scrub.  Someone more knowledgable than me can probably provide examples.

I was frankly surprised that they went ahead with fueling after pushing T-0 to the end of the window.  I was expecting a replay of Thursday.  When the webcast started, I was worried that they would try to launch too close to the limit.

Perhaps it qualifies as one of the 7 COPV tests

[ugordan]

Perhaps it qualifies as one of the 7 COPV tests

Perhaps, but what do the last 2 minutes of the countdown really buy you in terms of COPV qualification? LOX load on the 1st stage is done by that point and it's finishing up on 2nd stage and the gas closeout is at T-1:30 IIRC and the real issue is really in the flight regime, the buoyant loads on the COPVs once the G forces build up during late 1st stage flight, like on CRS-7.

If they really had doubts about the COPVs, I really don't think they'd be experimenting with a payload as expensive and important as this. I think this was more in line with verifying the temperature sensors on what caused the previous scrub.

[Comga]

Interesting that they took the count to T-0:29 even after calling an abort for winds. Must have wanted to test out the out of family sensor fix to make sure it was really fixed.

That's what I thought, too.  I've never heard of continuing a count after calling a scrub.  Someone more knowledgable than me can probably provide examples.

I was frankly surprised that they went ahead with fueling after pushing T-0 to the end of the window.  I was expecting a replay of Thursday.  When the webcast started, I was worried that they would try to launch too close to the limit.

AIR, CRS/SpX-10 had an identified issue on the day of the first launch attempt, but went down to around T-15 seconds before Musk himself called the abort.  There were statements about if the count went below T-10 that turn around would be much longer. My assumption was that Musk called the abort when whatever the problem was did not resolve itself, but with the minimum margin to that hard limit. 
Perhaps 12 or so seconds was found to be cutting it to close, although SpaceX did launch SpX-10 the next day.

(That abort was very disappointing.  Some people were still counting 10! 9! 8!  $#!+!)

[DigitalMan]

Perhaps it qualifies as one of the 7 COPV tests

Perhaps, but what do the last 2 minutes of the countdown really buy you in terms of COPV qualification? LOX load on the 1st stage is done by that point and it's finishing up on 2nd stage and the gas closeout is at T-1:30 IIRC and the real issue is really in the flight regime, the buoyant loads on the COPVs once the G forces build up during late 1st stage flight, like on CRS-7.

If they really had doubts about the COPVs, I really don't think they'd be experimenting with a payload as expensive and important as this. I think this was more in line with verifying the temperature sensors on what caused the previous scrub.

My recollection was that one of the discussions (with Hans?) was that static fires also counted.

[Alexphysics]

Perhaps it qualifies as one of the 7 COPV tests

Perhaps, but what do the last 2 minutes of the countdown really buy you in terms of COPV qualification? LOX load on the 1st stage is done by that point and it's finishing up on 2nd stage and the gas closeout is at T-1:30 IIRC and the real issue is really in the flight regime, the buoyant loads on the COPVs once the G forces build up during late 1st stage flight, like on CRS-7.

If they really had doubts about the COPVs, I really don't think they'd be experimenting with a payload as expensive and important as this. I think this was more in line with verifying the temperature sensors on what caused the previous scrub.

My recollection was that one of the discussions (with Hans?) was that static fires also counted.

I hate it that two different qualifications get mixed almost on every site I usually visit. One qualification is the propellant loading sequence qualification which will be done during DM-1, IFA and DM-2 and it'll be on the static fire and launch of the first two and the static fire of DM-2, that is 5 tests of the loading sequence. What does count now is the number of flights with the final Block 5 configuration (with a few caveats like the fact that engine design may not be finished yet and they need to modify it again but that's a whole different thing). They need 7 flights in that configuration and that means FLIGHTS, so if the thing doesn't take off, it doesn't count. This is in order to qualify the Falcon 9 launch vehicle as a whole and not the loading sequence. They are two different things even though both need the final COPV design to be on the rocket.

[DigitalMan]

Thanks for clarifying.

[Skylab]

The link to today's webcast has been posted in the Updates thread.

[geza]

My recollection was that one of the discussions (with Hans?) was that static fires also counted.

I hate it that two different qualifications get mixed almost on every site I usually visit. One qualification is the propellant loading sequence qualification which will be done during DM-1, IFA and DM-2 and it'll be on the static fire and launch of the first two and the static fire of DM-2, that is 5 tests of the loading sequence. What does count now is the number of flights with the final Block 5 configuration (with a few caveats like the fact that engine design may not be finished yet and they need to modify it again but that's a whole different thing). They need 7 flights in that configuration and that means FLIGHTS, so if the thing doesn't take off, it doesn't count. This is in order to qualify the Falcon 9 launch vehicle as a whole and not the loading sequence. They are two different things even though both need the final COPV design to be on the rocket.

If 7 flights are required with the latest config, why we count the prop. loadings separately? No flight without propellant...

[Alexphysics]

My recollection was that one of the discussions (with Hans?) was that static fires also counted.

I hate it that two different qualifications get mixed almost on every site I usually visit. One qualification is the propellant loading sequence qualification which will be done during DM-1, IFA and DM-2 and it'll be on the static fire and launch of the first two and the static fire of DM-2, that is 5 tests of the loading sequence. What does count now is the number of flights with the final Block 5 configuration (with a few caveats like the fact that engine design may not be finished yet and they need to modify it again but that's a whole different thing). They need 7 flights in that configuration and that means FLIGHTS, so if the thing doesn't take off, it doesn't count. This is in order to qualify the Falcon 9 launch vehicle as a whole and not the loading sequence. They are two different things even though both need the final COPV design to be on the rocket.

If 7 flights are required with the latest config, why we count the prop. loadings separately? No flight without propellant...

Because the propellant load sequence is different for crewed launches (or in the case of DM-1 and IFA, simulations of crewed launches). On crewed launches the COPV's are loaded two hours before launch. NASA wants SpaceX to test this on DM-1, IFA and DM-2 to certify this loading sequence for crewed launches. The Falcon 9 is certified separately and I'm sure that one of the boxes that will have to be checked before that is the loading sequence but since there's no info on that part, I can't say with 100% certainty that's what will happen. It would be super great if someone from the press asks how both certifications will be brought together and how they'll approve the Falcon 9 for crewed missions.

[Lar]

They said they were going to cut off S1 after sep, but they did keep it on for 2-3 secs

[nzguy]

What causes the chunks of ice? It seems they are coming from near the those lateral nozzles?

[A12]

What is the tumbling object in the video stream ?

[yokem55]

For a performance reference, Stage 1 MECO was at about 9400km/hr.

[kevinof]

Liquid oxygen "warms" and boils off. Once  it's vented it it purged out and hits the cold of space and freezes again.

Perfectly normal.
 

What causes the chunks of ice? It seems they are coming from near the those lateral nozzles?

[niwax]

For a performance reference, Stage 1 MECO was at about 9400km/hr.

I got 9500km/h for 2650m/s. Quite a bit over typical reusable in velocity alone, and possibly on a more efficient trajectory.

[Lar]

What causes the chunks of ice? It seems they are coming from near the those lateral nozzles?

(fan) There is always ice.  It is routine.

(mod) Expect we will have a lot of discussion about the thermal blanket's alleged tear or slippage. Let's try to keep that to a reasonable level, eh chaps? Thanks!