Falcon Heavy might match first version of SLS.

[Exoscientist]

SpaceX has said the improvement of the performance with the Falcon 9 v1.2 would be about 30%. With the upgraded engines and densified propellants applied to the Falcon Heavy, the max payload of the FH to LEO could then also be increased from 53 metric tons to 70 mT.

If so, then the FH, at a ca. $100 million cost, could match the capability of the initial Block I version of the gigadollar SLS at 70 metric tons to LEO.

First Falcon Heavy Launch Scheduled for Spring.

by Jeff Foust  September 2, 2015

http://spacenews.com/first-falcon-heavy-launch-scheduled-for-spring/

Actually, I'm dubious of the cited payload of the Block I SLS as 70 mT. I think it's likely to be closer to 90 mT:

SLS for Return to the Moon by the 50th Anniversary of Apollo 11, page 5: A 90+ metric ton first launch of the SLS.

http://exoscientist.blogspot.com/2013/09/sls-for-return-to-moon-by-50th.html

Bob Clark

[MajorLeaugeRocketScience]

This is pretty cool stuff

[Shpaget]

Can we agree not to use milliteslas for mass?

1000 kg is 1 t, not 1 mT.

[Requia]

A) SpaceX is charging ~125 million on average per ISS delivery, and that's not even the full payload for at least some of those. I really really doubt given that number the Falcon Heavy is only 100 million a launch. Probably that figure is the estimate assuming successful recovery.

Those Falcon 9 1.2 upgrades are probably a long way off. Certainly not this spring.

C) Densified propellants? Kerosene is Kerosene.

[_Augustus_]

A) SpaceX is charging ~125 million on average per ISS delivery, and that's not even the full payload for at least some of those. I really really doubt given that number the Falcon Heavy is only 100 million a launch. Probably that figure is the estimate assuming successful recovery.

Those Falcon 9 1.2 upgrades are probably a long way off. Certainly not this spring.

C) Densified propellants? Kerosene is Kerosene.

Actually they're building 1.2 now...

[MajorLeaugeRocketScience]

Falcon 9 v1.2 is currently scheduled for Early December I believe...

[Frozen_Heart]

Ok. First thing is that the 54 ton measurement people are using was for the fuel crossfeed version, which is no longer being worked on. Without that it will lose a chunk of payload capacity.

Second thing is that the Falcon Heavy is meant to be reusable from the start which will cut its capacity in half.

Realistically its payload will be 20 tons, maybe 30 tons with this upgraded version.

Those Falcon 9 1.2 upgrades are probably a long way off. Certainly not this spring.

Next flight is 1.2 which is this year.

[StrandedonEarth]

C) Densified propellants? Kerosene is Kerosene.

Super-chilled propellants. Colder=denser

[Exoscientist]

Can we agree not to use milliteslas for mass?

1000 kg is 1 t, not 1 mT.

Understandable for people with a background in electrical engineering. Unfortunately, if you just say "ton" Americans won't know if you mean metric tons or English tons.

Bob Clark

- - - Updated - - -

Actually they're building 1.2 now...

Yes. I've read conflicting reports on whether the next launch in November will be the v1.2.

Bob Clark

[maccollo]

I will go out on a limb and say it will not be capable of doing that.

SpaceX has upped the mass of the F9 on their website to 540 tonnes (a tonne is always a metric ton btw), so I assume the 1400 tonne mass for the FH also reflects the new mass with the 1.2 F9 components.

If so then it would have a payload fraction of 4.76%.

It's more probable that this increase in performance allows the falcon heavy to meet the 50 tonne target to begin with.

[Kryten]

Even if you accept the LEO figures as taken, it won't be matching Block I SLS, because as planned it's never actually going to send anything to LEO. F9's upper stage is anaemic even compared to iCPS, and wouldn't get you similar figures to higher energy locations such as lunar orbit.

[Lukaszenko]

Ok. First thing is that the 54 ton measurement people are using was for the fuel crossfeed version, which is no longer being worked on. Without that it will lose a chunk of payload capacity.

Second thing is that the Falcon Heavy is meant to be reusable from the start which will cut its capacity in half.

They gave up on the asparagus staging? I'm really disappointed to hear that. I thought it was a sure thing. Any reason? Too difficult?

[SargeRho]

Not worth the extra mass and complexity, since it would only ever be used on a small fraction of flights.

[Lukaszenko]

Mass should't matter as long as it still adds delta-V, so I guess that narrows it down to complexity. Sad to see it go though

[SciMan]

Actually, the 70 tonne to LEO figure might have been plausible, assuming 3 things: Don't save fuel for recovery of core stages, use fuel crossfeed, and the F9v1.2 upgrades.

The decision to not pursue fuel crossfeed is a real letdown.

Still probably get significantly better payload to LEO if it doesn't set aside fuel for landing the stages, which has always been an option (even if unpopular with SpaceX).

[Nibb31]

Crossfeed is complex to work with. You don't really want to be leaking propellant when there are 9 open flames nearby. The switchover event has to run smoothly without starving or blowing up your turbopump and the separation can be tricky. It also makes core stages and booster stages fundamentally different, which increases cost.

Edited September 7, 2015 by Nibb31

[fredinno]

Would crossfeed be more difficult than modifying an engine to be throttleable?

[Nibb31]

Would crossfeed be more difficult than modifying an engine to be throttleable?

Those aren't really comparable. More difficult, I don't know. More risky, definitely.

Edited September 7, 2015 by Nibb31

[mellojoe]

We've had throttleable engines since ... well, since the late 70's I believe. (perhaps earlier) Detaching fuel lines can easily cause fuel spillover (think those few drops when you take the pump handle out of your car's gas tank) which can be disastrous at the temperatures the main engines produce.

[Lukaszenko]

Wikipedia and even SpaceX's own website still talk about the crossfeed as if it's a sure thing. Where can I read about the latest news?

[Exoscientist]

Wikipedia and even SpaceX's own website still talk about the crossfeed as if it's a sure thing. Where can I read about the latest news?

You could register on the http://forum.nasaspaceflight.com/ board. The people on there are pretty knowledgeable. Once registered try their search function.

Bob Clark

Edited September 10, 2015 by Exoscientist

[FishInferno]

Even if FH won;t have the same payload capacity as the SLS, once you take cost into account the FH wins by a long shot.

And I also believe that SpaceX plans to keep selling expendable versions of their rockets for a time for those who are willing to pay the price for the extra payload.

[Exoscientist]

I will go out on a limb and say it will not be capable of doing that.

SpaceX has upped the mass of the F9 on their website to 540 tonnes (a tonne is always a metric ton btw), so I assume the 1400 tonne mass for the FH also reflects the new mass with the 1.2 F9 components.

If so then it would have a payload fraction of 4.76%.

It's more probable that this increase in performance allows the falcon heavy to meet the 50 tonne target to begin with.

That is high but not completely unprecedented. The Saturn V had a payload fraction of 4.7%. And the Space Shuttle had a payload fraction for the total mass sent to orbit of 6%.

Bob Clark

[cantab]

Wouldn't the crossfeed help the reusability? It means the boosters drain their fuel more quickly which in turn means that when they decouple they have less distance to boostback. It would also mean that a payload mass that demands the boosters be expended without crossfeed might permit booster recover with it; depending on the payloads customers want to launch this could let the crossfeed pay for itself.

[kStrout]

Wouldn't the crossfeed help the reusability? It means the boosters drain their fuel more quickly which in turn means that when they decouple they have less distance to boostback. It would also mean that a payload mass that demands the boosters be expended without crossfeed might permit booster recover with it; depending on the payloads customers want to launch this could let the crossfeed pay for itself.

Only if you are trying to recover all the cores, they probably aren't, at least at first because it's expensive and finicky. But they probably will be in the future, maybe they will add crossfeed then? Anyways not only is the Heavy wayyy cheaper it will almost definitely be flying before the SLS.

Also my solution to the whole ton = 2000lbs or 1000kg is to use tons with the imperial system, and megagrams for metric, just try saying it, it sounds awesome.