SpaceX Falcon Heavy Discussion (Thread 6)

[LouScheffer]

Do I recall correctly that someone posted estimates of the characteristics of Falcon Heavy's upper stage based on Falcon Heavy's payload capability as reported by the NASA Launch Services Program's launch-vehicle performance website?  If so, could someone please point me toward it?

Yes, I did this.   Here is an analysis that fits the LSP data almost perfectly, giving very plausible numbers for the second stage.

[IainMcClatchie]

How are you all getting Falcon Heavy performance numbers from LSP?

Are we talking about the Performance Query page?

SpaceX claims Falcon Heavy will put 53 tonnes into LEO, but I can't get LSP to emit performance numbers for FH at all.  Is the issue that SpaceX doesn't have a sufficiently robust payload adapter?

LSP doesn't seem to have an option of GEO or GEO-xx00 m/s orbits.  It does have an option for escape trajectories, and that's the only orbit for which I can get FH payload projections.

Is there some magic inclination (apparently not 28.5 degrees) that gets LSP to tell me what FH can do to LEO?

[Coastal Ron]

SpaceX claims Falcon Heavy will put 53 tonnes into LEO...

On the Falcon Heavy SpaceX page they say it can put 63.8mT into LEO.

However there is much debate as to whether the current version is capable of that off the shelf, or if they would need to finish developing some hardware (or software) to reach that amount.

[Nomadd]

How are you all getting Falcon Heavy performance numbers from LSP?

Are we talking about the Performance Query page?

SpaceX claims Falcon Heavy will put 53 tonnes into LEO, but I can't get LSP to emit performance numbers for FH at all.  Is the issue that SpaceX doesn't have a sufficiently robust payload adapter?

LSP doesn't seem to have an option of GEO or GEO-xx00 m/s orbits.  It does have an option for escape trajectories, and that's the only orbit for which I can get FH payload projections.

Is there some magic inclination (apparently not 28.5 degrees) that gets LSP to tell me what FH can do to LEO?

53 tonnes is an ancient number from before they even started on it, including crossfeed. With Merlin improvements and stretches, even with no crossfeed, it's 63.8 tonnes now.

[Slarty1080]

Does anyone have any idea how much additional LEO payload might reasonably be achieved by stretching the FH upper stage?

[spacenut]

I have asked that same question about stretching the upper stage, but I still haven't gotten any clear answers.  Does anyone know. 

Someone did take the initial testing of Raptor (about 100 ton thrust) with a 5m upperstage the same length, and said it would get 70-75 tons to LEO.

[Alexphysics]

How are you all getting Falcon Heavy performance numbers from LSP?

Are we talking about the Performance Query page?

SpaceX claims Falcon Heavy will put 53 tonnes into LEO, but I can't get LSP to emit performance numbers for FH at all.  Is the issue that SpaceX doesn't have a sufficiently robust payload adapter?

LSP doesn't seem to have an option of GEO or GEO-xx00 m/s orbits.  It does have an option for escape trajectories, and that's the only orbit for which I can get FH payload projections.

Is there some magic inclination (apparently not 28.5 degrees) that gets LSP to tell me what FH can do to LEO?

53 tonnes is an ancient number from before they even started on it, including crossfeed. With Merlin improvements and stretches, even with no crossfeed, it's 63.8 tonnes now.

And Elon said that it could carry more with some optimizations which seems to indicate that the number is like a moderate estimate of the full performance.

[envy887]

Does anyone have any idea how much additional LEO payload might reasonably be achieved by stretching the FH upper stage?

A larger upper stage (either Raptor or MVac) mainly helps with recovery and to LEO. To LEO, I would ballpark 5-10% improvement from a mild (~25%) stretch. Adding crossfeed would get another 10-15% improvement on top of that. Best case with a large Raptor upper stage and crossfeed, FH could be pushing 90 t to LEO, or about 60 t with 3x ASDS recovery.

But it is unlikely to ever be able to send a fully fueled Orion all the way to TLI, if that's why you're wondering. To high energy orbits, the added dry mass of the larger upper stage mostly cancels what you gained in LEO payload.

[Celestar]

Does anyone have any idea how much additional LEO payload might reasonably be achieved by stretching the FH upper stage?

A larger upper stage (either Raptor or MVac) mainly helps with recovery and to LEO. To LEO, I would ballpark 5-10% improvement from a mild (~25%) stretch. Adding crossfeed would get another 10-15% improvement on top of that. Best case with a large Raptor upper stage and crossfeed, FH could be pushing 90 t to LEO, or about 60 t with 3x ASDS recovery.

But it is unlikely to ever be able to send a fully fueled Orion all the way to TLI, if that's why you're wondering. To high energy orbits, the added dry mass of the larger upper stage mostly cancels what you gained in LEO payload.

Would Raptor (in the non-vacuum version) instead of MVac actually yield any payload improvement? MVac appears to have about 348s of ISP, so the increase by swapping in a raptor would be what? 8-10 seconds? But you have a much heavier engine, and a much heavier tank. Also even with an MVac there are discussions about it being too powerful for Orion. A raptor would be about four times the thrust ...

Celestar

[TrueBlueWitt]

Tank stretch is incredibly cheap mass wise, and would barely move the needle of Stage 2 PMF for heavy payload like Orion while providing a lot more Delta v. First stage would lose some, but also makes up some by not having to throttle down as soon to keep G levels down. M-vac is powerful enough the upper stage grav losses with increased mass shouldn't hurt much either.

[Proponent]

LSP doesn't seem to have an option of GEO or GEO-xx00 m/s orbits.  It does have an option for escape trajectories, and that's the only orbit for which I can get FH payload projections.

Forum member M129K has explained.

[PM3]

Spacenews article on Falcon Heavy and how the Air Force deals with it

Falcon Heavy’s first commercial launch to pave the way for reusable rockets in national security missions

Before Falcon Heavy can launch its first NSSL mission, it has to get through the complete nonrecurring design validation, which will include two more launches, Kendall said. “Arabsat and STP-2 are going to serve as two final milestones to complete the certification plan,” he said. The Air Force Space and Missile Systems Center and Aerospace “still have some work remaining for the complete design certification.”

[Scylla]

https://twitter.com/elonmusk/status/1111803711766970368

[Scylla]

https://twitter.com/elonmusk/status/1111805464797302784

[meekGee]

https://twitter.com/elonmusk/status/1111805464797302784

I'm surprised he still cares.

Technologically, he switched tracks to SS/SH a long time ago, choosing to already mark the end of life of the F9 family.

SS/SH has no competition at all.

He should move on from ULA comparisons, it's just bad vibes over something that doesn't matter.

[Alexphysics]

https://twitter.com/elonmusk/status/1111805464797302784

I'm surprised he still cares.

Technologically, he switched tracks to SS/SH a long time ago, choosing to already mark the end of life of the F9 family.

SS/SH has no competition at all.

He should move on from ULA comparisons, it's just bad vibes over something that doesn't matter.

It's obvious why he cares, SpaceX will bid for the USAF contracts with F9 and FH and they may win 60% of the 25 missions that will be distributed between the two chosen launch providers. That's 15 missions and with an average of $100m each one (which is unlikely, there will probably be some that could go as high as $200m and the lowest price could be just $90m), that means $1.5b which would be helpful for SS/SH and Starlink. Defending the F9/FH systems against ULA's lies is not a waste of time imo.

[meekGee]

https://twitter.com/elonmusk/status/1111805464797302784

I'm surprised he still cares.

Technologically, he switched tracks to SS/SH a long time ago, choosing to already mark the end of life of the F9 family.

SS/SH has no competition at all.

He should move on from ULA comparisons, it's just bad vibes over something that doesn't matter.

It's obvious why he cares, SpaceX will bid for the USAF contracts with F9 and FH and they may win 60% of the 25 missions that will be distributed between the two chosen launch providers. That's 15 missions and with an average of $100m each one (which is unlikely, there will probably be some that could go as high as $200m and the lowest price could be just $90m), that means $1.5b which would be helpful for SS/SH and Starlink. Defending the F9/FH systems against ULA's lies is not a waste of time imo.

I get that.

It'd be nice if they won more of course.

But the tact that the government continues to award ULA allows the market price to remain high, and this at the end works to SpaceX's advantage: much higher margin when launching other companies' payloads, and a higher barrier of entry for payload competitors such as oneWeb.

This will continue to happen even into Starship days, and is a good thing.

[clongton]

I wouldn't dismiss the Falcon family so soon. Plans change to accommodate changing conditions all the time. I know Musk is promoting Starship, as he should, but I believe there will continue to be a market for Falcon and Dragon for some time to come. Especially now that they are both reusable I'd be willing to bet that he'll keep an assembly/refurb line going, even if it's slow paced, just to support that market , which will continue to grow. He's not going to cede that market to someone else, especially since it will continue to generate much needed cash for the Starship HSF program. Colonizing Mars is going to be really expensive and the Falcon-9 and Falcon-H have a long term role to play in contributing to that funding need.

Remember, Elon signed a 20-year lease for Launch Complex 39A and there has been a *LOT* of SpaceX money sunk into it. He'll be wanting to make a really good ROI from that.

Starship will fly, but its OML is not well suited to satellite delivery, which are designed to ride at and be inserted from the top. I know there are designs out there like Chomper, but that's a long way off imo. He's got too much else on his plate at the moment. Falcon will be the SpaceX satellite delivery system of record for some time to come.

[TrueBlueWitt]

I wouldn't dismiss the Falcon family so soon. Plans change to accommodate changing conditions all the time. I know Musk is promoting Starship, as he should, but I believe there will continue to be a market for Falcon and Dragon for some time to come. Especially now that they are both reusable I'd be willing to bet that he'll keep an assembly/refurb line going, even if it's slow paced, just to support that market , which will continue to grow. He's not going to cede that market to someone else, especially since it will continue to generate much needed cash for the Starship HSF program. Colonizing Mars is going to be really expensive and the Falcon-9 and Falcon-H have a long term role to play in contributing to that funding need.

Remember, Elon signed a 20-year lease for Launch Complex 39A and there has been a *LOT* of SpaceX money sunk into it. He'll be wanting to make a really good ROI from that.

Starship will fly, but its OML is not well suited to satellite delivery, which are designed to ride at and be inserted from the top. I know there are designs out there like Chomper, but that's a long way off imo. He's got too much else on his plate at the moment. Falcon will be the SpaceX satellite delivery system of record for some time to come.

If there is one thing we know about Elon? That he doesn't subscribe to the sunk cost fallacy.

[clongton]

If there is one thing we know about Elon? That he doesn't subscribe to the sunk cost fallacy.

It depends entirely on whether or not he is making or losing money while getting the ROI.
If he is then he subscribes - until he's not. Then he doesn't.
He know when to hold 'em and when to fold 'em.