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

[The Roadie]

One TSM is already removed!

Reusing the term "TSM" is just a bit jarring because there's no T and it's not an M. The SpX Reaction Fixture has various inserts to carry the hold-downs, and the FH compression bridges. But the GSE plumbing for liquids and gasses go through two QD (Quick Disconnect) plates, one for LOX (blue) plus other things, and one for RP-1 (red) and other things. And they're mounted horizontally, and would be blasted by the exhaust plume if it wasn't for hinged flap doors that protect them right after liftoff.

This is a close up of a Michael Seeley picture I used for a recent educational trivia quiz inthe FB SpX group I have a little to do with.

[ChrisC]

http://www.launchphotography.com/Delta_4_Atlas_5_Falcon_9_Launch_Viewing.html

The next SpaceX Falcon rocket from Cape Canaveral will be the second launch of the Falcon Heavy, from pad 39A, carrying the Arabsat 6A communication satellite on April TBD, in the early evening EDT. Sunset is about 7:45pm. The launch window stretches about two hours. The two first stage side boosters will land back at Cape Canaveral about eight minutes after launch.

Is my understanding correct that this launch TIME will not move in one direction or the other as the date moves?

I'm judging the feasibility of going down to see this one; a late evening launch is doable for me, but not an overnight one.

[Alexphysics]

http://www.launchphotography.com/Delta_4_Atlas_5_Falcon_9_Launch_Viewing.html

The next SpaceX Falcon rocket from Cape Canaveral will be the second launch of the Falcon Heavy, from pad 39A, carrying the Arabsat 6A communication satellite on April TBD, in the early evening EDT. Sunset is about 7:45pm. The launch window stretches about two hours. The two first stage side boosters will land back at Cape Canaveral about eight minutes after launch.

Is my understanding correct that this launch TIME will not move in one direction or the other as the date moves?

I'm judging the feasibility of going down to see this one; a late evening launch is doable for me, but not an overnight one.

Being a GTO mission, I'd say it is likely the window will not move too much.

[ChrisC]

Is my understanding correct that this launch TIME will not move in one direction or the other as the date moves?

I'm judging the feasibility of going down to see this one; a late evening launch is doable for me, but not an overnight one.

Being a GTO mission, I'd say it is likely the window will not move too much.

I agree, thanks.  Since this is not yet an updates-only thread (hint hint), I'll inquire further ...

Why not just schedule the launch for a more convenient time, say early afternoon, just to make it easier on the launch and ground ops staff?  I'm not doubting SpaceX, I'm asking why not.  Since they're not trying to hit a particular inclined orbital plane (a la ISS or polar EO orbits), I would think they could just phase to the desired GEO orbital position later in the mission.  Drifting a GEO satellite from slot to slot doesn't take much, as long as you have some time, and so they could hit any slot they wanted with minor tweaks of the GTO-to-GEO transfer steps.

Is it because that extra week or two of phasing ultimately impacts the satcom operators business (e.g. two weeks of revenue), versus the frankly minor annoyance during launch week of having to time-shift the staff?

[Olaf]

https://twitter.com/SpaceXFleet/status/1104741874022133760

[2megs]

For a GTO launch, I don't believe the time of launch has meaningful impact on the amount of phasing involved. That's ultimately derived from the initial orbit and the longitude of the launch site, regardless of launch time.

What sometimes does matter is when the satellite initially enters daylight versus when its solar array deploys. Aligning those depends on the initial orbit and the time of day at the launch site, and so in the absence of other constraints the launch time is usually chosen to optimize that.

[Semmel]

I thought GTO launches are timed to maximize sun exposure for the sat and minimize its time in earth shadow. That means putting perigee into the shadow, which implies an evening launch.

[Alexphysics]

That's not true for every GTO missions, just look at the dozen or so SpaceX has launched during broad daylight. Sometimes it also has to do with other factors other than the sun exposure and all of that.

[Semmel]

That's not true for every GTO missions, just look at the dozen or so SpaceX has launches during broad daylight. Sometimes it also has to do with other factors other than the sun exposure and all of that.

You are probably right. Most of the GTO missions are in the evening, some are in the middle of the night, some are in the afternoon. I see only one in the morning (Eutelsat 117W).

Cutout from https://forum.nasaspaceflight.com/index.php?topic=43418.msg1702573#msg1702573 :

Local	LV	Core	Ret-	.	.	Mass	.	Mis-
2013-12-03  1741/-5	F9	.	.	SES-8	GTO	3183	C-40	7
2014-01-06  1706/-5	F9	.	.	Thaicom 6	GTO	3016	C-40	8
2014-08-05  0400/-4	F9	.	.	Asiasat 8	GTO	4535	C-40	11
2014-09-07  0100/-4	F9	.	.	Asiasat 6	GTO	4428	C-40	12
2015-03-01*2250/-5	F9	.	.	Eutelsat 115WB/ABS 3A	GTO	4159	C-40	16
2015-04-27  1903/-4	F9	.	.	TürkmenÄlem 52E/MonacoSAT	GTO	4707	C-40	18
2016-03-04  1835/-5	F9	.	S	SES-9	GTO	5271	C-40	22
2016-05-06  0121/-4	F9	1022	S	JCSAT-14	GTO	4696	C-40	24
2016-05-27  1740/-4	F9	1023.1	S	Thaicom 8	GTO	3025	C-40	25
2016-06-15  1029/-4	F9	.	S	Eutelsat 117W B & ABS-2A	GTO	4200	C-40	26
2016-08-14  0126/-4	F9	.	S	JCSAT-16	GTO	~4600	C-40	28
2016-09-01  0907/-4	F9	.	N/A	AMOS-6(destroyed in pad test)	GTO	5500	C-40	29
2017-03-16  0200/-4	F9	1030	X	Echostar 23	GTO	~5500	C-39A	32
2017-03-30  1827/-4	F9	1021.2	S	SES-10	GTO	5282	C-39A	33
2017-05-15  1921/-4	F9	1034	X	Inmarsat 5 F4	GTO	6086	C-39A	35
2017-06-23  1510/-4	F9	1029.2	S	BulgariaSat-1	GTO	3669	C-39A	37
2017-07-05  1938/-4	F9	1037	X	Intelsat 35e	GTO	6761	C-39A	39
2017-10-11  1853/-4	F9	1031.2	S	SES-11/Echostar 105	GTO	5200	C-39A	44
2017-10-30  1534/-4	F9	1042	S	Koreasat-5A	GTO	3700	C-39A	45
2018-01-31  1625/-5	F9	1032.2	X	GovSat-1 (SES-16)	GTO	4230	C-40	49
2018-03-06  0033/-5	F9	1044	X	Hispasat 1F (30W-6)	GTO	6092	C-40	51
2018-05-11  1614/-4	F9	1046	S	Bangabandhu-1	GTO	3.7k	C-39A	55
2018-06-04  0045/-4	F9	1040.2	X	SES-12	GTO	5384	C-40	57
2018-07-22  0150/-4	F9	1047	S	Telstar 19 Vantage	GTO	7075	C-40	59
2018-08-07  0118/-4	F9	1046.2	S	Merah Putih (Telkom 4)	GTO	5800	C-40	61
2018-09-10  0045/-4	F9	1049	S	Telstar 18 Vantage/Apstar-5C	GTO	7060	C-40	62
2018-11-15  1546/-5	F9	1047.2	S	Es'hail 2	GTO	5300	C-39A	64

However, this is starting to get mildly off topic and will loose track on the topic if we continue. Conclusion is: Based on previous launches we cannot predict what the launch time will do in case of slippage.

[Roy_H]

Why is this satellite being launched on FH instead of F9. Significantly heavier satellites, Telstar Vantage, have been launched to GTO and booster recovered. Is it possibly a dual launch with Hellas Sat 4/SaudiGeoSat-1?

Arabsat-6A is part of the two-satellite Arabsat-6G program for Arabsat and is the second of Lockheed Martin's modernized LM 2100 series satellites to complete assembly. The other satellite in the Arabsat 6G program, Hellas Sat 4/SaudiGeoSat-1, recently completed assembly and was also shipped to Sunnyvale in November of 2017 for testing.

[DatUser14]

Why is this satellite being launched on FH instead of F9. Significantly heavier satellites, Telstar Vantage, have been launched to GTO and booster recovered. Is it possibly a dual launch with Hellas Sat 4/SaudiGeoSat-1?

Arabsat-6A is part of the two-satellite Arabsat-6G program for Arabsat and is the second of Lockheed Martin's modernized LM 2100 series satellites to complete assembly. The other satellite in the Arabsat 6G program, Hellas Sat 4/SaudiGeoSat-1, recently completed assembly and was also shipped to Sunnyvale in November of 2017 for testing.

Hellas Sat 4 launched with GSat 31 on an Ariane 5 Feb 5th 2019.

[Tomness]

Why is this satellite being launched on FH instead of F9. Significantly heavier satellites, Telstar Vantage, have been launched to GTO and booster recovered. Is it possibly a dual launch with Hellas Sat 4/SaudiGeoSat-1?

Those were for GTO-2400 to GTO-1800. This is for GEO Direct Insertion with hopefully full recovery of the Boosters & main stage. Show AF, NASA & future customers what FH can do.

[PM3]

Those were for GTO-2400 to GTO-1800. This is for GEO Direct Insertion with hopefully full recovery of the Boosters & main stage. Show AF, NASA & future customers what FH can do.

What is the source for direct GEO? Could not find any confirmation for that.

[ZachS09]

https://www.reddit.com/r/SpaceXLounge/comments/84q1qm/comparing_gto_and_direct_to_geo_launch_profiles/

The direct-to-GEO capability for a fully-expendable Falcon Heavy is about 13 tons.

[gongora]

This flight is not expected to be expendable.

[Roy_H]

https://www.reddit.com/r/SpaceXLounge/comments/84q1qm/comparing_gto_and_direct_to_geo_launch_profiles/

The direct-to-GEO capability for a fully-expendable Falcon Heavy is about 13 tons.

Capability is not proof that this is a GEO mission. I agree it is likely but not proof.

[OccasionalTraveller]

HellasSat-4 is indicative of the performance required. It massed 6,495 kg at launch (wet mass, with propellants) and was delivered to GTO-1500. That is, 1500 m/s additional delta-V required to circularise and null out the inclination.

A similar performance is likely required here. I don't think we know the launch mass but it's either going to be the same - requiring the launch vehicle to do more work to reach an acceptable transfer orbit - or it will carry more fuel, making it heavier. F9 is only listed as capable of 5.5 tonnes to GTO-1800 with recovery. It has achieved more, but only through being expended.

Also recall that this mission has been on the books since 2015 as a Heavy mission. As I recall, F9's listed capability has increased since then, but probably not by enough to warrant transferring away from FH. It's likely that it's always been slated for recovery of the boosters.

[ZachS09]

I never said that this mission was expendable. I was just trying to find a source that showed Falcon Heavy's direct-to-GEO payload mass for recoverable mode, but the only thing I could find was the fully expendable version.

[FutureSpaceTourist]

https://twitter.com/thesheetztweetz/status/1106602646792781824

Arabsat 6A – the second flight of @SpaceX Falcon Heavy – is scheduled to launch no earlier than April 7 at 6:36 pm ET (22:36 UTC), sources familiar with the plans tell me.

[Rondaz]

Second SpaceX Falcon Heavy flight gets April 7 launch date: Sources

PUBLISHED 5 HOURS AGO

Michael Sheetz

@THESHEETZTWEETZ

https://www.cnbc.com/2019/03/15/spacex-falcon-heavy-arabsat-6a-launch-april-7-sources.html