Commercial Super Heavy Lift Launchers?

[Downix]

The SpaceX website only gives a ~12 metric ton payload of FH to GTO now:

http://www.spacex.com/falcon_heavy.php

Mass to Geosynchronous Transfer Orbit (GTO):   12,000 kg (26,460 lb)
Inclination   27 degree

The poor GTO payload of Falcon Heavy relative to it's LEO payload suggests the vehicle could really use a high energy upper stage eg Raptor or even just the addition of some sort of third stage.
Even just something derived from the F1 second stage or a solid upper stage probably would greatly increase those GTO numbers.

Which is something I've been saying. I would have rather kept the Merlin-1C for now and focused on even a Hydrolox version of the Merlin, without the staged-combustion of Raptor, just to get a high-energy upper stage going. Instead of developing the Merlin-1D, this hypothetical engine would open up far more. A Falcon Heavy using Falcon 9 1.0 stages, Merlin 1C's, but the estimated hydrolox upper stage performance, would push more to GTO than this FH, and would rival the GTO performance of the Falcon 9 1.1.

[Downix]

The poor GTO payload of Falcon Heavy relative to it's LEO payload suggests the vehicle could really use a high energy upper stage eg Raptor or even just the addition of some sort of third stage.

It probably would benefit from such, but it's not even consistent with the Falcon 9 GTO payload. There's some other limitation at work here. The most likely candidate I'm aware of is that they want the flexibility to change launch sites, and are advertising considerably less than the best they could do with a KSC launch with an instantaneous launch window so they have sufficient margin to do this.

As there are no GTO launches requiring 19 tons, saving a slot at KSC in exchange for payload they would not have used is a good trade.

No, it fits very well with the Falcon 9's 4.8 metric ton GTO capability. Similar mass growth for the Delta IV when going from the Medium to the Heavy as well, where it goes from 3.9 metric tons to 13.1 metric tons, but with a high-energy upper stage (something FH lacks).

[ArbitraryConstant]

No, it fits very well with the Falcon 9's 4.8 metric ton GTO capability. Similar mass growth for the Delta IV when going from the Medium to the Heavy as well, where it goes from 3.9 metric tons to 13.1 metric tons, but with a high-energy upper stage (something FH lacks).

What FH has is crossfeed.

[Downix]

No, it fits very well with the Falcon 9's 4.8 metric ton GTO capability. Similar mass growth for the Delta IV when going from the Medium to the Heavy as well, where it goes from 3.9 metric tons to 13.1 metric tons, but with a high-energy upper stage (something FH lacks).

What FH has is crossfeed.

Which is good for the LEO performance in compensating for gravity losses. It is *not* good for GTO, where the majority of the burn is outside of the atmosphere. By the point of GTO burn, the first stage and boosters are already gone.

For comparison, the Proton with the similar kerolox kick-stage can lift about 20 metric tons to LEO, but only 5 metric tons to GTO. This means Protons LEO to GTO ratio is about 4:1 . This is a similar LEO to GTO pattern as Falcon Heavy has, going from 50 to 12, which is also about 4:1. Crossfeed does improve, but it still cannot get over the basic issue, the SpaceX vacuum engine is a high density engine, not a high-energy engine. As a result, the Delta IV Heavy, going from 26 metric tons to 13 metric tons, has a ratio of 2:1, twice as much GTO performance per ton LEO performance, compared to the Falcon Heavy.

And there's nothing wrong with that. They are focusing on two different approaches to the problem. SpaceX's way has worked fine for the Russians for years, as the Blok-DM demonstrates.

[hkultala]

No, it fits very well with the Falcon 9's 4.8 metric ton GTO capability. Similar mass growth for the Delta IV when going from the Medium to the Heavy as well, where it goes from 3.9 metric tons to 13.1 metric tons, but with a high-energy upper stage (something FH lacks).

What FH has is crossfeed.

Which is good for the LEO performance in compensating for gravity losses. It is *not* good for GTO, where the majority of the burn is outside of the atmosphere. By the point of GTO burn, the first stage and boosters are already gone.

For comparison, the Proton with the similar kerolox kick-stage can lift about 20 metric tons to LEO, but only 5 metric tons to GTO. This means Protons LEO to GTO ratio is about 4:1 .

This is a similar LEO to GTO pattern as Falcon Heavy has, going from 50 to 12, which is also about 4:1. Crossfeed does improve, but it still cannot get over the basic issue, the SpaceX vacuum engine is a high density engine, not a high-energy engine.

Proton has launched Intelsat 22 which was 6200 kg.
Which means like GTO-LEO-ratio of 30%.

Though it seems this was with breze-m upper stage with hypergolics, which actually have _lower_ isp than kerosine.

And compared to "traditional boosters", cross-feed actually makes gravity losses WORSE as it causes the boosters to separate earlier, and makes the center core close-to-full (bad T/W) vs almost empty after booster separation.

What cross-feed does it that it practically converts the boosters into a "full stage", though in case of FH the core engine nozzles are not optimized as vacuum nozzles but first stage nozzles, which takes away some of the advantage.

Adding stages should give more benefit in high-energy orbits than it gives in low-energy orbits, so FH should have better GTO to LEO-ratio than F9.

F9-v1.1 GTO-to-leo percentage:

4.85t / 13.15t = 36%

based in this what FH _should_ lift to GTO:
53t * 0.36 = 19t.

So FH should lift something like 20t to GTO if the known values for F9-1.1 are true.

So, either
1) F9-1.1 can lift more to LEO than 13.15t
2) The FH 12t GTO number is without crossfeed
3) The FH numbers (at least the GTO number) is from vanderberg with bootleg manouver which costs quite a lot of fuel. (because they cannot yet lunch FH from cape, they cannot sell numbers they cannot deliver, and that 12t is number they are selling, 53t is number they are only hyping "for the future")
4) 2+3

As a result, the Delta IV Heavy, going from 26 metric tons to 13 metric tons, has a ratio of 2:1, twice as much GTO performance per ton LEO performance, compared to the Falcon Heavy.

And there's nothing wrong with that. They are focusing on two different approaches to the problem. SpaceX's way has worked fine for the Russians for years, as the Blok-DM demonstrates.

Delta with LH upper stage scales much, better, yes, but the difference should not be so big.

[MATTBLAK]

I know it would be a silly number of first stage engines - 45 - but I've been wondering in this or that thread how a Falcon 9-based 'Super Heavy' would perform - this is assuming that somehow, Falcon X never happens or gets badly deferred. Recipe: 5x Version 1.1 stages ganged together - propellant cross-feed from 2x boosters only; the other two would be jettisoned relatively early, Upper Stage: 1x Raptor powered LOX/LH2 5-meter diameter stage. Payload to LEO? I don't know, but it would have to be in excess of 75 metric tons.

[MikeAtkinson]

So, either
1) F9-1.1 can lift more to LEO than 13.15t
2) The FH 12t GTO number is without crossfeed
3) The FH numbers (at least the GTO number) is from vanderberg with bootleg manouver which costs quite a lot of fuel. (because they cannot yet lunch FH from cape, they cannot sell numbers they cannot deliver, and that 12t is number they are selling, 53t is number they are only hyping "for the future")
4) 2+3

5) the upper stage is optimised for F9 (only difference for FH is a possible tank stretch).

[Downix]

No, it fits very well with the Falcon 9's 4.8 metric ton GTO capability. Similar mass growth for the Delta IV when going from the Medium to the Heavy as well, where it goes from 3.9 metric tons to 13.1 metric tons, but with a high-energy upper stage (something FH lacks).

What FH has is crossfeed.

Which is good for the LEO performance in compensating for gravity losses. It is *not* good for GTO, where the majority of the burn is outside of the atmosphere. By the point of GTO burn, the first stage and boosters are already gone.

For comparison, the Proton with the similar kerolox kick-stage can lift about 20 metric tons to LEO, but only 5 metric tons to GTO. This means Protons LEO to GTO ratio is about 4:1 .

This is a similar LEO to GTO pattern as Falcon Heavy has, going from 50 to 12, which is also about 4:1. Crossfeed does improve, but it still cannot get over the basic issue, the SpaceX vacuum engine is a high density engine, not a high-energy engine.

Proton has launched Intelsat 22 which was 6200 kg.
Which means like GTO-LEO-ratio of 30%.

Though it seems this was with breze-m upper stage with hypergolics, which actually have _lower_ isp than kerosine.

And compared to "traditional boosters", cross-feed actually makes gravity losses WORSE as it causes the boosters to separate earlier, and makes the center core close-to-full (bad T/W) vs almost empty after booster separation.

What cross-feed does it that it practically converts the boosters into a "full stage", though in case of FH the core engine nozzles are not optimized as vacuum nozzles but first stage nozzles, which takes away some of the advantage.

Adding stages should give more benefit in high-energy orbits than it gives in low-energy orbits, so FH should have better GTO to LEO-ratio than F9.

F9-v1.1 GTO-to-leo percentage:

4.85t / 13.15t = 36%

based in this what FH _should_ lift to GTO:
53t * 0.36 = 19t.

So FH should lift something like 20t to GTO if the known values for F9-1.1 are true.

So, either
1) F9-1.1 can lift more to LEO than 13.15t
2) The FH 12t GTO number is without crossfeed
3) The FH numbers (at least the GTO number) is from vanderberg with bootleg manouver which costs quite a lot of fuel. (because they cannot yet lunch FH from cape, they cannot sell numbers they cannot deliver, and that 12t is number they are selling, 53t is number they are only hyping "for the future")
4) 2+3

As a result, the Delta IV Heavy, going from 26 metric tons to 13 metric tons, has a ratio of 2:1, twice as much GTO performance per ton LEO performance, compared to the Falcon Heavy.

And there's nothing wrong with that. They are focusing on two different approaches to the problem. SpaceX's way has worked fine for the Russians for years, as the Blok-DM demonstrates.

Delta with LH upper stage scales much, better, yes, but the difference should not be so big.

Intelsat-22 was launched on a Proton 8K82KM 14S43 Phase III, which has more LEO performance than the model Proton I discussed above (I used the 8K82K for simpler math). The model of Proton used an upgraded 3rd stage, which when combined with the Briz-M increases the total performance by almost 10%.

In addition, hypergols can have comparable isp to kerolox, and a few hypergol solutions are even able to reach a performance rate just below hydrolox. But not the case of the Briz-M here, which has an impulse of only just slightly less than the Falcon's upper stage. However, the Briz-M is also significantly lighter, as it does not need to perform any of the orbital burn.

[GalacticIntruder]

It seems to me SpaceX's top priority is to always be the lowest cost launch provider. Developing a hydrolox Upper really only makes sense for BEO. They can compete pretty well in most sat launches with RP1 and FH. If they are serious about TMI then I think they must develop that higher Isp capability.

Maybe they can buy the manufacturing rights to a LH2 upper because in house development would be very expensive and not be as good as off the shelf engines.

[Downix]

It seems to me SpaceX's top priority is to always have the low cost lunches. Developing a hydrolox Upper really only makes sense for BEO. They can compete pretty well in most sat launches with RP1 and FH. If they are serious about TMI then I think they must develop that higher Isp capability.

Maybe they can buy the manufacturing rights to a LH2 upper because in house development would be very expensive and not be as good as off the shelf engines.

They can modify their existing engine to run on hydrolox for cheaper than buying the manufacturing rights to another engine. Not as good as the RL-10, but the RL-10 is the single largest cost factor for the EELV's price increase as well. Perfection is the enemy of good enough. A hydrolox Merlin would be more than sufficient for this job.

And yes, it can be done. Aerojet has a long history of modifying existing engines to run on multiple fuel. The Aerojet LR-87 is distinctive for running on Kerolox, Hydrolox *and* Hypergols.

Alternatively, they can buy a Hydrolox upper stage from another vendor.

[sewand]

It seems to me SpaceX's top priority is to always have the low cost lunches.

I recommend the ham sandwich.

I recommend the roast Falcon, though it's a bit on the Heavy side.

[darkenfast]

It seems to me SpaceX's top priority is to always have the low cost lunches.

I recommend the ham sandwich.

I recommend the roast Falcon, though it's a bit on the Heavy side.

That was fowl.

[Joel]

On a side note, Musk said in the Mars Society video that reusability will take away half of the payload. To be more precise, he said that a good expendable rocket could get 4 % of the liftoff mass to orbit. And then adding reusability will then costs two percentage points, leaving 2 %.

So, know knows, maybe FH is deliberately overdimensioned now and the idea is for it to be 25 mT in reusable mode. Or 35 mT with a high-isp US.

EDIT:
Another way of interpreting this is that SpaceX needs to scale up FH a factor 2 in order for it to make 50 mT reusable. In expendable mode, the same rocket might be able to lift 100 mT.

[aero]

The expend verses reuse idea troubles me. If you really do have a $50 million (my number) machine capable of half your total launch mass requirement in reusable mode at say for example, $10 million fuel and refurb. costs, would you really throw it away just to launch the total mass in one go?

Why would you throw away $50 million to launch mass that could be launched for $20 million? What might exist at a mass of 100 tonnes that could not be split into two or more pieces for less than $30 million?

I think that expending a Falcon Heavy will be rare once it becomes reusable. Maybe not though, assembly on orbit is very expensive.