SpaceX Falcon 9 FT - ORBCOMM-2 - Dec. 21, 2015 (Return To Flight) DISCUSSION

[Zed_Noir]

This could simply be to reassure that the Vac still operates as expected.

Could someone please summarize the changes between the RTF MVac and the MVac that most recently performed in space? Are there any?

AIUI the major change from previous F9 upper stage is that SpaceX is using a new pneumatic mechanism to separate the stages sited within the Merlin Vac engine nozzle bell.

[The Roadie]

Larger bell extension,  longer stage for additional propellant, running with densified propellants,  presumably full thrust increased injector pressure.

[Chris Bergin]

Converted this into the discussion thread for the ORBCOMM-2 mission, as it covers both RTF and what is now the RTF mission.

Update only thread is live.

Party thread will be later.

[cro-magnon gramps]

Converted this into the discussion thread for the ORBCOMM-2 mission, as it covers both RTF and what is now the RTF mission.

Update only thread is live.

Party thread will be later.

For those looking:  L2 UPDATE THREAD ONLY: http://forum.nasaspaceflight.com/index.php?topic=38667.0


Edit> add Public side
For those looking for Public Side UPDATE THREAD ONLY: http://forum.nasaspaceflight.com/index.php?topic=38148.0

[Space Ghost 1962]

I wonder about that restart test. Even if it is on the extremely cautious side. Maybe there are larger changes than we knew about in the restarting tech? Maybe it is only the new upper stage that is capable of loiter time long enough to do direct GEO insertion? Both Elon Musk and Gwynne Shotwell emphasized Falcon 9 can do it but maybe the ability is there only now? It would be still in time for any Airforce launch.

It's not possible for SpaceX to do a vacuum test on Merlin at McGregor.

Yes. How do you "stress" a US, in the environment?

This could simply be to reassure that the Vac still operates as expected.

Like an earlier US test they did with F9 v1.0, you'll get from US:
 * max performance (iSP, thrust, burn duration, restart)
 * residual and/or depletion
 * thermal environment
 * max acceleration/fatigue on components

Won't perfectly match  the results as on post staging full duration burn to depletion, but then you're not risking it all on the roulette wheel

Clearly they are still stung badly by the US failure. Two ways to come back from this: they either are cautious, or overly "bada$$" following a successful RTF. Predict the latter.

[Barrie]

I wonder about that restart test. Even if it is on the extremely cautious side. Maybe there are larger changes than we knew about in the restarting tech? Maybe it is only the new upper stage that is capable of loiter time long enough to do direct GEO insertion? Both Elon Musk and Gwynne Shotwell emphasized Falcon 9 can do it but maybe the ability is there only now? It would be still in time for any Airforce launch.

I see the test of the US as what they call 'regression testing' in IT - not just making sure changes have the desired effect, but that they don't have any undesired effects.  So you run the full test suite, not just the parts that seem relevant to the changes made.

[Ben the Space Brit]

From the Update Thread:

Preps for the Full Duration Static Fire are now taking place. Upcoming potentially later this week.

Does that mean that we're into the pad flow for OG-2? Have the payloads arrived at the Cape?

[rpapo]

From the Update Thread:

Preps for the Full Duration Static Fire are now taking place. Upcoming potentially later this week.

Does that mean that we're into the pad flow for OG-2? Have the payloads arrived at the Cape?

The Full Duration Static Fire spoken of is the one at McGregor...

[Jarnis]

From the Update Thread:

Preps for the Full Duration Static Fire are now taking place. Upcoming potentially later this week.

Does that mean that we're into the pad flow for OG-2? Have the payloads arrived at the Cape?

The Full Duration Static Fire spoken of is the one at McGregor...

...and since this is a the first full duration firing of a 9-engine F9 FT ("v1.2") config, there is obviously a considerable chance that they may have to try this a couple of times if problems show up. Individual engines they of course have already tested a lot, but not with a full 9-engine flight stage config.

[TOG]

From the Update Thread:

Preps for the Full Duration Static Fire are now taking place. Upcoming potentially later this week.

Does that mean that we're into the pad flow for OG-2? Have the payloads arrived at the Cape?

The Full Duration Static Fire spoken of is the one at McGregor...

...and since this is a the first full duration firing of a 9-engine F9 FT ("v1.2") config, there is obviously a considerable chance that they may have to try this a couple of times if problems show up. Individual engines they of course have already tested a lot, but not with a full 9-engine flight stage config.

Will the full duration firing include coast and restart to simulate re-entry and landing?

[Lars-J]

From the Update Thread:

Preps for the Full Duration Static Fire are now taking place. Upcoming potentially later this week.

Does that mean that we're into the pad flow for OG-2? Have the payloads arrived at the Cape?

The Full Duration Static Fire spoken of is the one at McGregor...

...and since this is a the first full duration firing of a 9-engine F9 FT ("v1.2") config, there is obviously a considerable chance that they may have to try this a couple of times if problems show up. Individual engines they of course have already tested a lot, but not with a full 9-engine flight stage config.

Will the full duration firing include coast and restart to simulate re-entry and landing?

No, it is usually just a test to verify that the 9 engines can function together for the duration of the 1st stage burn (~3 minutes), and that the loads/vibrations/heat can be managed by the stage structure.

[Ronsmytheiii]

Might be awhile on the next burn, Texas is really getting hammered with rain right now

http://www.cnn.com/2015/10/25/us/texas-louisiana-flooding/index.html

[The Roadie]

The M1-VAC is tested in McGregor without the niobium skirt extension. The longer bell and higher pressure should be giving it 180,000 lb thrust in vacuum.

The densified propellants may require some thermal changes or at least analysis, as the RP-1 is now chilled and the LOX is more chilled. Remember the Fregat upper stage failure in Aug 2014? Missing thermal insulation on a shared mounting bracket allowed cold Helium to freeze a hydrazine feed line. And it happened during the coast phase before the Fregat's second ignition. Burn profile similar to SES9.

The parallels have to be known at SpaceX.

https://en.wikipedia.org/wiki/Fregat

[Comga]

Might be awhile on the next burn, Texas is really getting hammered with rain right now

http://www.cnn.com/2015/10/25/us/texas-louisiana-flooding/index.html

Looks pretty good for McGregor (Waco area) for the coming week.

[docmordrid]

The M1-VAC is tested in McGregor without the niobium skirt extension. The longer bell and higher pressure should be giving it 180,000 lb thrust in vacuum.
>

210,000 lbf for F9 FT

[WHAP]

Based on typical range rules, can SpaceX target 12/1 before the Atlas launch on 12/3?  Would they if it only gave them one try before having to stand down? 

[Comga]

Based on typical range rules, can SpaceX target 12/1 before the Atlas launch on 12/3?  Would they if it only gave them one try before having to stand down? 

https://twitter.com/pbdes/status/658913128420384768

SpaceX President Shotwell Oct 27 at CASBAA convention: Current target is early Dec for Falcon 9 v1.2 Full Thrust upgrade w/ Orbcomm sats.

Because Shotwell said "early Dec" and not specifically Dec 1, this looks like an unsurprising acknowlegement that SpaceX is getting in line behind the OA-4 Atlas launch.

Does an OA-4 thread say how many days they could keep recycling if something like weather rules out their scheduled launch day?

[sdsds]

Because Shotwell said "early Dec" and not specifically Dec 1, this looks like an unsurprising acknowlegement that SpaceX is getting in line behind the OA-4 Atlas launch.

The other interpretation of her comment is that SpaceX has yet to decide whether to ask for Dec 1, or as you put it "get in line."

[Jim]

Saw a fairing entering the Cape this afternoon

[DatUser14]

nevermind, already in the updates thread.