SpaceX Falcon Heavy : Arabsat 6A : LC-39A : April 11, 2019 - DISCUSSION

[ZachS09]

Couldn't they coast after SECO2 and use that delta-v in a third burn to raise perigee and decrease inclination? That would probably get them closer to GEO, even if they did the 3rd burn after only a few hours and well short of apogee.

That’s something SpaceX has not done before with F9 or FH.

I would prefer they do that third burn at apogee since I always do that in Orbiter 2016 when using their F9 addon.

[LouScheffer]

Couldn't they coast after SECO2 and use that delta-v in a third burn to raise perigee and decrease inclination? That would probably get them closer to GEO, even if they did the 3rd burn after only a few hours and well short of apogee.

For increasing apogee, this does not help (in fact it hurts), since this is most efficiently done at perigee (Oberith effect).   

But for decreasing inclination, it could be helpful.   It all depends on how long you can wait.  At the bottom, it's a bad idea - the triangle inequality always favors doing one burn with both components.   But at the top, the cross velocity for a given inclination is much less, and it's helpful.   The crossover point must be somewhere in the middle.

I'm not sure this is practical, though.  The standard mission is optimized for a short coast (less than one orbit).  The extended coast package  (more helium, more batteries, more nitrogen for thrusters, etc), needs to go for 6 hours since this is needed for direct GEO insertion.   It's not clear an intermediate coast option would be worth the extra trouble - just use the extended coast option and wait until apogee.

[envy887]

If they do relight at apogee of a standard GTO, how close to GEO can they get? It should be quite a bit better than the 1583 m/s deficit by doing inclination reduction at perigee, although that does depend on the mass addition from the coast kit, and prop loss to boiloff.

[LouScheffer]

If they do relight at apogee of a standard GTO, how close to GEO can they get? It should be quite a bit better than the 1583 m/s deficit by doing inclination reduction at perigee, although that does depend on the mass addition from the coast kit, and prop loss to boiloff.

If coasting, re-light, and a longer mission were free, they could indeed do better.   They have about 600 m/s more than they need for a basic GTO with 1800 m/s to go from Cape inclination.   So if they wait until the top to use this delta-V, they could run the deficit down to 1200 m/s or thereabouts.  This would leave the second stage in a very long term intermediate orbit, with a several thousand km perigee.

[Chris Bergin]

ARTICLE: As Falcon Heavy celebrates anniversary, SpaceX manifest aligns -

https://www.nasaspaceflight.com/2019/02/falcon-heavy-anniversary-spacex-manifest-aligns/

- By Michael Baylor

https://twitter.com/NASASpaceflight/status/1093216459931701248

[gongora]

Looks like Lockheed may have switched from Volga-Dnepr to Antonov Airlines for the flight.  Antonov filed a request on Jan. 28 for transport of Arabsat 6A.  Neither the Volga-Dnepr or Antonov application is showing a resolution yet, and a quick check on FlightAware didn't show any A124 planes at Moffett this week.  (I need to resubscribe to FlightRadar24 so I can get alerts again.)

[Rondaz]

SpaceX’s next Falcon Heavy reaches milestone as third booster arrives in FL

By Eric Ralph Posted on February 12, 2019

https://www.teslarati.com/spacex-falcon-heavy-milestone-three-boosters-arrive-in-florida/?mc_cid=ad330c2f91&mc_eid=60eb267dc3

[fvasnier]

Do you have any estimation about potential delays for the launch?

I plan to come from Europe for the launch and I feel like the gap between DM-1 and the Falcon Heavy is a little bit too optimistic... What are your thoughts? Thx!

[scr00chy]

Do you have any estimation about potential delays for the launch?

I plan to come from Europe for the launch and I feel like the gap between DM-1 and the Falcon Heavy is a little bit too optimistic... What are your thoughts? Thx!

SpaceX will probably need at least a few weeks after DM-1 to reconfigure the launch pad, assemble the Falcon Heavy and do a static fire. So I'd say, realistically, Arabsat won't launch until late March at the earliest (and that's dependant on DM-1 launching on March 2, which is also far from certain).

[ChrisC]

"A few weeks" for pad turnover is excessive, per earlier discussion in this thread.  We don't know how long it will take, but some here think it would be a lot shorter, like a week.

As for your travel plans, my condolences.  We've all played this game, and it's not fun sometimes.  It's best to have airfares (and hotel bookings) that can be rescheduled for free or cheap.  Just stay on top of this thread and jump on any changes if they are announced.  Join L2 to get more advance word.

[Orbiter]

Do you have any estimation about potential delays for the launch?

I plan to come from Europe for the launch and I feel like the gap between DM-1 and the Falcon Heavy is a little bit too optimistic... What are your thoughts? Thx!

SpaceX will probably need at least a few weeks after DM-1 to reconfigure the launch pad, assemble the Falcon Heavy and do a static fire. So I'd say, realistically, Arabsat won't launch until late March at the earliest (and that's dependant on DM-1 launching on March 2, which is also far from certain).

We have no metric for how quickly SpaceX can turnaround LC-39A from F9 to FH. Agreed that March 7th is unlikely though.

[gongora]

"A few weeks" for pad turnover is excessive, per earlier discussion in this thread.  We don't know how long it will take, but some here think it would be a lot shorter, like a week.

It may depend on how much FH processing you can get done while a F9 flight campaign is being conducted.  I would guess the F9 -> FH transition (including launch vehicle assembly) is probably a little longer than FH -> F9.

[scr00chy]

"A few weeks" for pad turnover is excessive, per earlier discussion in this thread.  We don't know how long it will take, but some here think it would be a lot shorter, like a week.

My few weeks include FH assembly and static fire.

[scr00chy]

Ben Cooper's Launch Photography now shows this launch as "late March" (as expected).

[Spindog]

Along these lines it would be nice to separate falcon heavy launches from manned launches. Do we know if SpaceX has any plans to configure pad 40 for either falcon heavy or manned launches?

[Alexphysics]

Along these lines it would be nice to separate falcon heavy launches from manned launches. Do we know if SpaceX has any plans to configure pad 40 for either falcon heavy or manned launches?

Pad 40 can't be configured for Falcon Heavy as it is right now and for crewed launches it would take a while to get the tower ready and another crew access arm and all that stuff, not really worth the try

[Star One]

Along these lines it would be nice to separate falcon heavy launches from manned launches. Do we know if SpaceX has any plans to configure pad 40 for either falcon heavy or manned launches?

Pad 40 can't be configured for Falcon Heavy as it is right now and for crewed launches it would take a while to get the tower ready and another crew access arm and all that stuff, not really worth the try

It would be a waste of time and money being as Falcon has a limited shelf life.

[gongora]

Along these lines it would be nice to separate falcon heavy launches from manned launches. Do we know if SpaceX has any plans to configure pad 40 for either falcon heavy or manned launches?

Manned launches will be 1-2 a year, and FH won't be a lot of flights either.  It's not a big deal.  It's just drawing attention right now because the manned system is starting to go through its test flights.

[Coastal Ron]

Along these lines it would be nice to separate falcon heavy launches from manned launches. Do we know if SpaceX has any plans to configure pad 40 for either falcon heavy or manned launches?

Manned launches require the entire gantry system - the big tower next to the launch pad that has the crew access arm and the tower escape system. SLC-40 doesn't have enough room to build these there, and even if it did it would take years to build that type of infrastructure.

SpaceX leased LC-39A specifically to support both crew and Falcon Heavy flights, so they have built their infrastructure to support both. Reconfiguring between flights will likely end up being a relatively quick (i.e. I'm guessing a week) operation. Considering the number of Falcon Heavy flights in the backlog, this should not be a problem.

[russianhalo117]

Along these lines it would be nice to separate falcon heavy launches from manned launches. Do we know if SpaceX has any plans to configure pad 40 for either falcon heavy or manned launches?

Manned launches require the entire gantry system - the big tower next to the launch pad that has the crew access arm and the tower escape system. SLC-40 doesn't have enough room to build these there, and even if it did it would take years to build that type of infrastructure.

SpaceX leased LC-39A specifically to support both crew and Falcon Heavy flights, so they have built their infrastructure to support both. Reconfiguring between flights will likely end up being a relatively quick (i.e. I'm guessing a week) operation. Considering the number of Falcon Heavy flights in the backlog, this should not be a problem.

There is an EA for FH with options for VI on SLC-40 (Amended for a new SLC-40A/B configuration). It would only be executed upon demand for FH or USAF request.