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

[Surfdaddy]

Good to see all three booster cores down safely and to hear that the fairings are down intact and in reusable condition.

If nothing else, Elon Musk can rightfully claim to have changed the face of rocketry. What was previously considered to be so high-concept that only NASA or some other state space agency could possibly attempt it has been achieved by SpaceX instead: Mostly-reusable launch vehicles with loss of hardware pulled down to a bare minimum.

The paradigm has changed; ULA, Arianespace and all the other developers and manufactures of launch vehicles now have to accept and follow the path SpaceX and Blue Origin are treading. Any launch vehicle that does not include reusable boosters is going to have a hard time surviving the bean-counters' scrutiny.

I am amazed and appalled that SpaceX has never been awarded the Collier Trophy (basically the Nobel Prize for aerospace engineering). As I understand it, they haven’t even been a finalist since the last Falcon 1 flight. I think Falcon Heavy alone deserves it; if they fly two FH missions this year and fly crew to ISS, they better win it for 2019!

This is one reason I stopped my subscription to AW&ST after about 35 years. They seem to cover the entrenched aerospace industry but awards seemed to ignore SpaceX. I decided not to support the old interests any longer.

[Steven Pietrobon]

1 44186U 19021A   19102.02912470 -.00000769  00000-0  00000+0 0  9996
2 44186  22.9623  12.6558 8697825 179.4741  18.6070  0.74408419    03

327 km Perigee
89815 km Apogee
22.96 degrees inclination

Using https://gtocalc.github.io/, the delta-v to GTO is about 1,508 m/s.

Using my calculator I get 1507.5 m/s, but with optimum inclination changes, I get 1502.1 m/s.

http://www.sworld.com.au/steven/space/gto.zip

Delta-V calculator by Steven S. Pietrobon. 22 Dec 2018.
Enter negative perigee height to exit program.
Enter negative final orbit for geosynchronous orbit.

Enter initial perigee height (km): 327
Enter initial apogee height (km): 89815
Enter required inclination change (deg): 22.96
Enter final orbit height (km): -1
Geosynchronous altitude = 35786.0 km

Burn at 89815.0 km: theta1 = 22.96 deg, dv1 =  956.5 m/s
Burn at 35786.0 km: theta2 =  0.00 deg, dv2 =  551.0 m/s
dv = 1507.5 m/s

Burn at 89815.0 km: theta1 = 21.66 deg, dv1 =  946.0 m/s
Burn at 35786.0 km: theta2 =  1.30 deg, dv2 =  556.2 m/s
dv = 1502.1 m/s

[soltasto]

1 44186U 19021A   19102.02912470 -.00000769  00000-0  00000+0 0  9996
2 44186  22.9623  12.6558 8697825 179.4741  18.6070  0.74408419    03

327 km Perigee
89815 km Apogee
22.96 degrees inclination

Using https://gtocalc.github.io/, the delta-v to GTO is about 1,508 m/s.

Using my calculator I get 1507.5 m/s, but with optimum inclination changes, I get 1502.1 m/s.

http://www.sworld.com.au/steven/space/gto.zip

Delta-V calculator by Steven S. Pietrobon. 22 Dec 2018.
Enter negative perigee height to exit program.
Enter negative final orbit for geosynchronous orbit.

Enter initial perigee height (km): 327
Enter initial apogee height (km): 89815
Enter required inclination change (deg): 22.96
Enter final orbit height (km): -1
Geosynchronous altitude = 35786.0 km

Burn at 89815.0 km: theta1 = 22.96 deg, dv1 =  956.5 m/s
Burn at 35786.0 km: theta2 =  0.00 deg, dv2 =  551.0 m/s
dv = 1507.5 m/s

Burn at 89815.0 km: theta1 = 21.66 deg, dv1 =  946.0 m/s
Burn at 35786.0 km: theta2 =  1.30 deg, dv2 =  556.2 m/s
dv = 1502.1 m/s

Getting very similar results with mine: https://github.com/AleLovesio/delta-v-to-GTO

Current Orbit: 327.0000 km x 89815.0000 km x 22.9600 degrees;
Apogee Speed: 734.5589 m/s; Perigee Speed: 10548.5644 m/s; delta v to this orbit: 0.0000


Super-sync transfer.

First maneuver:
Perigee changed to 35786km
Inclination changed to 1.3018 degrees
Current Orbit: 35786.0000 km x 89815.0000 km x 1.3018 degrees;
Apogee Speed: 1589.2208 m/s; Perigee Speed: 3625.9884 m/s; delta v to this orbit: 946.1898


Second maneuver:
Apogee changed to 35786km
Inclination changed to 0 degrees
Current Orbit: 35786.0000 km x 35786.0000 km x 0.0000 degrees;
Apogee Speed: 3074.9218 m/s; Perigee Speed: 3074.9218 m/s; delta v to this orbit: 1502.4543


Total delta v to GEO: 1502.4543 m/s

[Steven Pietrobon]

SpaceX has claimed 10,000+ kg to GTO with 3x downrange landing. A5 ECA has never lifted 10,000 kg to GTO, and 3x downrange landing would definitely be cheaper, though they might need another ASDS.

Ariane 5 regularly flies payloads greater than 10 t. The last few missions to GTO:

VA241  9,123 kg
VA242 10,260 kg
VA243 10,827 kg
VA246 10,298 kg
VA247 10,052 kg

[Steven Pietrobon]

A 200x90000 km orbit has a perigee velocity of 10651 m/s. 200 km circular has a velocity of 7784 m/s, including the 5 degree inclination change (28 to 23 degrees) as a vector sum gives a delta-v of 3011 m/s for the GTO burn.

dv = sqrt(10651²+7784²-2*10651*7784*cos(5)) = 2975 m/s.

If you expended all 3 cores, (and enlarged the fairing, strengthened the payload adapter) how much can the FH boost to the same orbit? if it's more than Ariane 5 ECA then 'the world's most powerful launcher' is a fair statement.

Assuming a delta-V of 2975 m/s, using my calculator, FH expendable payload to same orbit as Arabsat 6A is 22.33 t.

http://www.sworld.com.au/steven/space/fh.zip

[ugordan]

Just for fun, let's see if I identified the boosters correctly in this annotated image. This is based off of the F9 User Guide engine layout and inferred from that that the MY is the one that has the black cable raceways 180 deg rotated w/respect the other 2 cores.

[ugordan]

A few fun clips from this mission that I didn't notice watching it live.

T+2:51: side booster boostback startup visible from other booster cam
T+3:10: center core plume clearly visible looking aft on side booster

Also, if you watch carefully you can see the side core attachments flexing up and down at a frequency of about 1.1 Hz from the moment the booster cameras appear on the webcast until the 2nd load-limiting shutdown at T+2:05, after which it damps down.

[Alexphysics]

Just for fun, let's see if I identified the boosters correctly in this annotated image. This is based off of the F9 User Guide engine layout and inferred from that that the MY is the one that has the black cable raceways 180 deg rotated w/respect the other 2 cores.

Yes, that's exactly the orientation. The MY booster, B1052, landed on LZ-1 and PY booster, B1053, landed on LZ-2.

Something that I have noticed from the webcast is that the center core moves the booster pusher mechanism right at reentry burn. I wonder why

[envy887]

SpaceX has claimed 10,000+ kg to GTO with 3x downrange landing. A5 ECA has never lifted 10,000 kg to GTO, and 3x downrange landing would definitely be cheaper, though they might need another ASDS.

Ariane 5 regularly flies payloads greater than 10 t. The last few missions to GTO:

VA241  9,123 kg
VA242 10,260 kg
VA243 10,827 kg
VA246 10,298 kg
VA247 10,052 kg

SYLDA isn't payload, it is additional rocket structure required to lift that payload. Can the lower berth attach fitting carry 10,000 kg? Falcon's can.

[ugordan]

Something that I have noticed from the webcast is that the center core moves the booster pusher mechanism right at reentry burn. I wonder why

Yeah, I noticed that too. I don't think it's actually moved on purpose, it just moves under the G load after ignition. If you compare the position of the pusher after booster sep, but prior to MECO it's in the same position. However, when you compare both of those two positions with the position during unpowered coast you can see it's relaxed during coast so that checks out.

[daedalus1]

SpaceX has claimed 10,000+ kg to GTO with 3x downrange landing. A5 ECA has never lifted 10,000 kg to GTO, and 3x downrange landing would definitely be cheaper, though they might need another ASDS.

Ariane 5 regularly flies payloads greater than 10 t. The last few missions to GTO:

VA241  9,123 kg
VA242 10,260 kg
VA243 10,827 kg
VA246 10,298 kg
VA247 10,052 kg

SYLDA isn't payload, it is additional rocket structure required to lift that payload. Can the lower berth attach fitting carry 10,000 kg? Falcon's can.

All of that mass including the SYLDA must be mounted on the lower berth. So yes.

[Ben the Space Brit]

It's worth noting that Kourou is a much more favourable location for launches to GTO than Cape Canaveral. Falcon Heavy managed similar mission performance to an Ariane-5 from a steeper inclination and with enough fuel reserve return its boosters and core.

[John Alan]

It's worth noting that Kourou is a much more favourable location for launches to GTO than Cape Canaveral. Falcon Heavy managed similar mission performance to an Ariane-5 from a steeper inclination and with enough fuel reserve return its boosters and core.

Thanks for stating clearly what I tried to say the other day... and IMHO did a poor job of doing so... 

...
If they can show final GEO-xxx.x orbit numbers that beat A5 launches from South America...
Then I think, some folks in Europe are going to have a "moment of clarity"... 

I honestly think there are folks at Arianespace, looking at the orbit numbers FH has put up using brute force to overcome the launch site location deficit... 
And realizing it's time to look past Ariane 6 (which has yet to fly) and get cracking on a reusable Ariane 7 system...

Because it now should be clear to them (IMHO) that Ariane 5 ECA (and even Ariane 6 (both the 62, and now 64)) are only stopgap national pride at break-even priced rockets... (IMHO - them looking at their internal numbers)

While those SpaceX folks just got back the whole rocket (minus about $20Mus true cost and 4.5 metric tonnes of hardware... R&D not included)

IF they do not start on some sort of Ariane "7" system that matches SpX's 90%+ reusable F9/FH NOW...
Then when SS/SH comes online, they will really be stuck... as NOBODY will fly with them at those prices...

SO... I believe...
This Arabsat 6A mission will go down as a real turning point in the history of rockets
FH Demo hinted hard this was coming... but it came off to the public as a stunt in some ways...
And especially after the next FH STP-2 mission flies... (which hopefully will meet all required USAF objectives  )...

This WAS the day when all the world's government run big space programs (EU, China, Russia, India, Japan) along with the US industrial space complex (Old Space) realize that they either get on the reusable bandwagon with some serious funding and R&D... OR become the laughing stock of the public at large... building million and billion dollar things just so you can shoot them off like fireworks to their demise... 

IMHO... 

[Vettedrmr]

Did anyone ever hear if the 2nd booster to land did/did not experience any landing gear crushing/lean?  I'm thinking it did, but long-range photography can do some strange things.

TIA, and have a good one,
Mike

[freda]

Hello.  I hope this is the correct thread; the SpaceX Fleet thread looked inactive on this, and a quick glance around did not show any other apparent Forum.

Is there any perspective or explanation around why OCISLY and Hollywod Tug delayed returning, started, then stopped?  Just curious.  Information below from Twitter/SpaceXFleet.

https://twitter.com/SpaceXFleet/status/1117148506601529347

[Vettedrmr]

Tug/towing problem?

[ZachS09]

My best hope is that the center core does not fall overboard.

[Nomadd]

Tug/towing problem?

Maybe a seas problem. There are a ludicrous number of wave/wind/current combinations and trying to tow a barge while keeping it fairly level can be an interesting exercise. Things like getting ballast off nominal can cause delays. Too little and it bounces around too much. Too much and you get waves over the deck.

[sghill]

Yes, but surely SpX can vary the duration of the re-entry burn to manage the speed; that's my question.  And I expect that this burn would (should?) be longer than normal burns due to the higher velocity at MECO.  Maybe just by a few seconds, but longer.

Or am I just missing the concept?

Have a good one,
Mike

I was at the last FH flight and also this one.  The boostback was clearly longer this time. Those of us with binoculars could see the plumes with zero difficulty, and we were all remarking how the boostback went on and on and on...

Plus, here's a bonus shot of FH on the way up and the moon in the same frame. I was really hoping it'd get closer so I could zoom in more, but it started to arc out from under the frame.

[smoliarm]

Looks like this is a second stage burn from FH launch - caught over Maledivean island Soneva Fushi with wide-angle lens:
http://spaceweathergallery.com/indiv_upload.php?upload_id=152980