Author Topic: The fate of SLS after Falcon Heavy debut  (Read 55462 times)

Offline SWGlassPit

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Re: The fate of SLS after Falcon Heavy debut
« Reply #60 on: 02/08/2018 09:09 pm »
The SLS will continue development, which would only make sense given that nearly all the flight hardware has been made for EM-1, and flight hardware is already in process for EM-2

That's the sunk-cost fallacy in action. The rational question is, is it worth spending another $15-20 billion to fly those missions ($3-4 billion per year times 5ish years), or is it better to pay termination costs and stop now?

While this is true, since when has Congress been rational?

Offline Khadgars

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Re: The fate of SLS after Falcon Heavy debut
« Reply #61 on: 02/08/2018 09:23 pm »
How can one discuss the relative merits of two rocket systems without acknowledging that one is throwaway and the other is reusable? The first SLS is going to go up in 4-5 years and then... it will be vaporized. Then you get to build another one.
Because when Falcon Heavy is flown in its partially reusable form (boosters and core recovered), it only gets Atlas 5-53x capability.  It is a "heavy lifter" only when it, too, is expended, and even then it falls short of even SLS Block 1.  It can't lift Orion beyond low earth orbit in a single launch, so multiple expended Falcon Heavies would be needed.  These expendable versions are going to cost substantially more than the numbers everyone sees on the SpaceX web site.

That's not to say that Falcon Heavy and other rockets won't be able to play a big role in NASA's deep space  program.  There should be plenty of opportunities for systems like these.

 - Ed Kyle

Well stated as always Ed.  Instead of all this useless bickering, why don't we celebrate what an exciting time we are now in!  Never has there been a better, more diverse time for Spaceflight than what we are entering.  Speaking for myself, I'm thoroughly enjoying this journey and if people would stop second guessing every decision, they might too.
Evil triumphs when good men do nothing - Thomas Jefferson

Offline RyanC

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Re: The fate of SLS after Falcon Heavy debut
« Reply #62 on: 02/09/2018 12:51 am »
SLS is now effectively dead-man-walking.

EM-1 is definitely flying, because metal is being bent on major portions.

EM-2 and the third flight? Less certain.

Regards this:

SLS, even the interim, limited Block 1 variant, has more payload capability than Falcon Heavy.[/i]

SLS Block I (which is the only one we're gonna get) places about 60 to 70 metric tons into LEO.

Falcon Heavy (Fully expendable) according to SpX, can place 63.8 metric tons into LEO.

Cost:
SLS Block I: $500M to $1+ Billion (more likely in excess of $1B.)

Falcon Heavy Expendable: $90M list price, but for purposes of calculations, assume $110M as a penalty price for dropping a recoverable launch vehicle into the ocean.

For the cost range of SLS Block I (70T into orbit), you can:

(Low End $500M): Buy four (4) FH, placing 240T into orbit.
(High End $1B): Buy nine (9) FH, placing 540T into orbit.

A distributed launch architecture is now feasible, thanks to the success of the FH Demo mission -- place your payload into orbit on flight #1, then place a fully fuelled departure stage into orbit on flight #2 to boost your payload beyond earth orbit.

Autonomous docking has only been practiced for the last few decades by the Russians, after all....

Offline Robotbeat

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Re: The fate of SLS after Falcon Heavy debut
« Reply #63 on: 02/09/2018 01:06 am »
How can one discuss the relative merits of two rocket systems without acknowledging that one is throwaway and the other is reusable? The first SLS is going to go up in 4-5 years and then... it will be vaporized. Then you get to build another one.
Because when Falcon Heavy is flown in its partially reusable form (boosters and core recovered), it only gets Atlas 5-53x capability.  It is a "heavy lifter" only when it, too, is expended, and even then it falls short of even SLS Block 1.  It can't lift Orion beyond low earth orbit in a single launch, so multiple expended Falcon Heavies would be needed.  These expendable versions are going to cost substantially more than the numbers everyone sees on the SpaceX web site.

That's not to say that Falcon Heavy and other rockets won't be able to play a big role in NASA's deep space  program.  There should be plenty of opportunities for systems like these.

 - Ed Kyle
You're relying on figures from the KSC ELV performance page, which has figures that are years out of date. For instance, FH can do about 16 tons through trans Mars insertion, which is about c3= 7km^2/s^2 on an *exceptionally* good opportunity. According to KSC's page, FH can only do 10t. So for high energy trajectories, FH can do about 60% better than the KSC page suggests.

And I fail to see why you'd use Orion if you had the option of cheaper and lighter Dragon... the smaller amount of on-board delta-v is compensated for by being lighter.

(Unless you put your deep space gateway in, like, a medium lunar orbit. But you shouldn't do that anyway.
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Offline su27k

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Re: The fate of SLS after Falcon Heavy debut
« Reply #64 on: 02/09/2018 02:17 am »
No direct impact, but FH in many ways cleared the way for BFR, which will have big impact on SLS.

Although just goes by some of the comments in this thread I wonder if even BFR can kill SLS, here's some of the arguments I predict we'll see when BFR flies:
1. BFR and SLS can compliment each other, why can't we have both?
2. BFR can't launch Orion, so SLS is still needed
3. SLS can send 30t+ to TLI in one launch, BFR couldn't, so SLS is superior!
4. No impact to SLS, remember BFR hasn't just come to the scene, it's x years late already...
5. But we have invested so many billions into SLS, it has hardware, we can't just cancel it
6. BFR hasn't demonstrated x number of flights per year, it's still powerpoint!

Now try replacing FH/BFR with Starship Enterprise, and most of the arguments still work, what does this tell you...
« Last Edit: 02/09/2018 02:28 am by su27k »

Offline mike robel

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Re: The fate of SLS after Falcon Heavy debut
« Reply #65 on: 02/09/2018 02:30 am »

And I fail to see why you'd use Orion if you had the option of cheaper and lighter Dragon... the smaller amount of on-board delta-v is compensated for by being lighter.

(Unless you put your deep space gateway in, like, a medium lunar orbit. But you shouldn't do that anyway.

Um, because after the ISS splashes and he builds the BFR he won't be using Dragon?

I expect both programs to drift right. Orion/SLS because of funding and BFR because of unforeseen technical problems in building a booster that large.  (As an aside, Musk essentially stated he learned that rockets are not LEGOs (TM) and they had to modify the boosters to fly as a Falcon Heavy and they were not just able to slap them together and fly.)

If Musk's BFR flies first and doesn't bankrupt him, then I expect even Congress could see there is no need to continue SLS/Orion, but it won't be instantaneous and there will be a lot of caterwauling.

If Orion/SLS flies first AND we actually have goals and strategy for the Moon, Mars, or whatever, then it will probably go for a while until Musk overtakes it and the Congress determines that there is no longer a need for a government manned space program.  (As examples, consider the US Army airmail fiasco or the time needed to do away with Horse Cavalry in favor of Armored Cavalry/Armor.  Notwithstanding that sometimes even Horse Cavalry finds a niche, even today.)

In any event, the main event has not happened yet.



Online Coastal Ron

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Re: The fate of SLS after Falcon Heavy debut
« Reply #66 on: 02/09/2018 03:46 am »
Because when Falcon Heavy is flown in its partially reusable form (boosters and core recovered), it only gets Atlas 5-53x capability.  It is a "heavy lifter" only when it, too, is expended, and even then it falls short of even SLS Block 1.  It can't lift Orion beyond low earth orbit in a single launch, so multiple expended Falcon Heavies would be needed.  These expendable versions are going to cost substantially more than the numbers everyone sees on the SpaceX web site.

That's not to say that Falcon Heavy and other rockets won't be able to play a big role in NASA's deep space  program.  There should be plenty of opportunities for systems like these.

It doesn't matter what the throw-weight is of the SLS or any other launch system, it only matters how they are used. For instance, there are really two approaches to doing human space exploration:

A. Single-launch architectures, which is what Apollo used and what the SLS is.
B. Multi-launch architectures, which allows many launch systems to be used.

For single-launch architectures the limitation is that you get diminishing returns the farther out you go, so in reality our Moon is the furthest NASA could go with humans. That was how far Apollo went, and the SLS is about the same as the Saturn V.

The other limitation is that if NASA mandates everything has to fly on the SLS, then that doesn't leave room for commercial or international partners to participate with their own transportation systems, nor does it allow for a way to reduce transportation costs as commercial and international partners innovate. And if NASA (i.e. the U.S. Government) allows partners to use their own transportation systems, then the need for the SLS is diminished.

Multi-launch architectures really are the future. The 450mT ISS was built this way, ULA is promoting it for Vulcan/ACES, and SpaceX plans to use it. No limitations on HSF architectures, and really no limitation on how far out humanity can go.

The original question is whether Falcon Heavy changes the fate of the SLS, but it's not about the Falcon Heavy or any other rocket - it's about the approach NASA (i.e. the U.S. Government) will rely upon for human spaceflight missions in the future. Maybe Falcon Heavy becomes the excuse to discuss and debate that, but I don't think anyone wants to replace one single-point-of-failure (SPOF) transportation with another one. The best way forward is to allow many launch vehicles to participate in expanding humanity out into space, and use a launch architecture that embraces that.

My $0.02
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline Steven Pietrobon

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Re: The fate of SLS after Falcon Heavy debut
« Reply #67 on: 02/09/2018 04:54 am »
Falcon Heavy Expendable: $90M list price, but for purposes of calculations, assume $110M as a penalty price for dropping a recoverable launch vehicle into the ocean.

$90M is the reusable price. Expendable is $270M according to the AST (see page 17 below). Still a lot cheaper per kg (270,000/63.8 = $4,200/kg) than SLS though ($1,000,000/93.1 = $10,740/kg).

https://www.faa.gov/about/office_org/headquarters_offices/ast/media/2018_AST_Compendium.pdf
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Patchouli

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Re: The fate of SLS after Falcon Heavy debut
« Reply #68 on: 02/09/2018 05:09 am »
Falcon Heavy Expendable: $90M list price, but for purposes of calculations, assume $110M as a penalty price for dropping a recoverable launch vehicle into the ocean.

$90M is the reusable price. Expendable is $270M according to the AST (see page 17 below). Still a lot cheaper per kg (270,000/63.8 = $4,200/kg) than SLS though ($1,000,000/93.1 = $10,740/kg).

https://www.faa.gov/about/office_org/headquarters_offices/ast/media/2018_AST_Compendium.pdf

$270M would be an acceptable expense for flagship missions which cost over a billion dollars.
« Last Edit: 02/09/2018 05:10 am by Patchouli »

Offline Proponent

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Re: The fate of SLS after Falcon Heavy debut
« Reply #69 on: 02/09/2018 12:45 pm »
A. Single-launch architectures, which is what Apollo used and what the SLS is.

I agree with your general point, but even SLS-based architectures are multi-launch for missions of any significance.  An Orion/SLS lunar sortie, for example, would require multiple launches.

Offline Proponent

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Re: The fate of SLS after Falcon Heavy debut
« Reply #70 on: 02/09/2018 12:50 pm »
Multiple launches are not a problem because it is so much cheaper than SLS that you could afford five or six for the price of one SLS launch. You also don't need expendable versions, you simple expend a used stage.

I wouldn't go so far as to say multiple launches are not a problem.  Rather, I'd point out that most SLS-based missions require multiple launches anyway.  So it's not a black-and-white distinction between single and multiple-launch artitectures, but a matter of how many launches.  All other things being equal, fewer is better.  That would be a point in favor of SLS, but, of course, all other things aren't equal.  And, before anyone decided to spend billion$ & billion$ on SLS, there should have been a comparison of SLS with commercial alternatives, but there wasn't.  And for there to have been a proper comparison, there would have had to have been defined objectives, but that did not exist either, and still doesn't.
« Last Edit: 02/09/2018 12:51 pm by Proponent »

Offline francesco nicoli

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Re: The fate of SLS after Falcon Heavy debut
« Reply #71 on: 02/09/2018 12:56 pm »
Falcon Heavy Expendable: $90M list price, but for purposes of calculations, assume $110M as a penalty price for dropping a recoverable launch vehicle into the ocean.

$90M is the reusable price. Expendable is $270M according to the AST (see page 17 below). Still a lot cheaper per kg (270,000/63.8 = $4,200/kg) than SLS though ($1,000,000/93.1 = $10,740/kg).

https://www.faa.gov/about/office_org/headquarters_offices/ast/media/2018_AST_Compendium.pdf

The way I interpret the data from SpaceX webiste is different.90M is for a third of the payload. The customer can chose to book the full capacity and do reusable, or book that capacity X3 and do expendable. The mistake is dividing the full R price by full capacity to have per kg costs.
The full capacity of FH to GTO is, according to the website, 26700 KG. Of this, 90M buys you 8000 kg to GTO. the full price to GTO is therefore 300,4M. The current pricing is higher than Falcon 9 it seems to me.....
« Last Edit: 02/09/2018 01:03 pm by francesco nicoli »

Offline Robotbeat

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Re: The fate of SLS after Falcon Heavy debut
« Reply #72 on: 02/09/2018 01:13 pm »
Falcon Heavy Expendable: $90M list price, but for purposes of calculations, assume $110M as a penalty price for dropping a recoverable launch vehicle into the ocean.

$90M is the reusable price. Expendable is $270M according to the AST (see page 17 below). Still a lot cheaper per kg (270,000/63.8 = $4,200/kg) than SLS though ($1,000,000/93.1 = $10,740/kg).

https://www.faa.gov/about/office_org/headquarters_offices/ast/media/2018_AST_Compendium.pdf
I doubt SpaceX's internal costs for FH expendable are anywhere near $270. Bet they're closer to $150m, particularly since they can use end of life cores for the side boosters.
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Offline francesco nicoli

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Re: The fate of SLS after Falcon Heavy debut
« Reply #73 on: 02/09/2018 01:30 pm »
Falcon Heavy Expendable: $90M list price, but for purposes of calculations, assume $110M as a penalty price for dropping a recoverable launch vehicle into the ocean.

$90M is the reusable price. Expendable is $270M according to the AST (see page 17 below). Still a lot cheaper per kg (270,000/63.8 = $4,200/kg) than SLS though ($1,000,000/93.1 = $10,740/kg).

https://www.faa.gov/about/office_org/headquarters_offices/ast/media/2018_AST_Compendium.pdf
I doubt SpaceX's internal costs for FH expendable are anywhere near $270. Bet they're closer to $150m, particularly since they can use end of life cores for the side boosters.

I am pretty sure, but what matters for competition is not the cost, but the price...

Offline Robotbeat

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Re: The fate of SLS after Falcon Heavy debut
« Reply #74 on: 02/09/2018 01:49 pm »
Falcon Heavy Expendable: $90M list price, but for purposes of calculations, assume $110M as a penalty price for dropping a recoverable launch vehicle into the ocean.

$90M is the reusable price. Expendable is $270M according to the AST (see page 17 below). Still a lot cheaper per kg (270,000/63.8 = $4,200/kg) than SLS though ($1,000,000/93.1 = $10,740/kg).

https://www.faa.gov/about/office_org/headquarters_offices/ast/media/2018_AST_Compendium.pdf
I doubt SpaceX's internal costs for FH expendable are anywhere near $270. Bet they're closer to $150m, particularly since they can use end of life cores for the side boosters.

I am pretty sure, but what matters for competition is not the cost, but the price...
SpaceX will likely try to get as much profit as they can while still outcompeting other comers. As they should, in order to pay back Falcon Heavy's development costs before BFR takes over.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline TrevorMonty

Re: The fate of SLS after Falcon Heavy debut
« Reply #75 on: 02/09/2018 02:14 pm »
NASA will not develop a lunar architecture that relies on single commercial LV. Present plan for HSF to moon is via DSG with SLS/Orion being vehicles of choice to deliver crew to DSG. I can't see NASA funding SpaceX to develop FH/Dragon combination for crew delivery to DSG without also funding another company eg Blue, ULA. NB the cost of that project would fund alot of SLS launches.

If SpaceX funded FH/Dragon combination for DSG then NASA may well use it for additional missions if price was right.


Offline notsorandom

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Re: The fate of SLS after Falcon Heavy debut
« Reply #76 on: 02/09/2018 02:16 pm »
Musk has stated many times now that he wants to retire the Falcons and Dragons as soon as possible. Does it make sense for NASA to start a BEO exploration program when the vendor wants to retire their product in 5 or so years? At this point the first question any proposed exploration program needs to ask is will the BRF happen? If the answer is no then the Falcon Heavy and maybe SLS likely do have an important role to play.

Lets imagine that BFR is successful and everything that SpaceX is promising with it. It would be better for NASA to wait for that to come online and buy it off the shelf. While a payload meant for the Falcon Heavy could launch on the BFR it would be underutilizing the capability of the BFR.

Imagine if NASA contracted to have a Moon lander launched on the Falcon Heavy. I doubt a lander could be made and ready to launch before the BFR, if it shows up when Musk is proposing. It would be a funny situation for the BFR to be launching a moon lander while itself being capable of landing on the moon because NASA contacted another company to build the lander.

Offline laszlo

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Re: The fate of SLS after Falcon Heavy debut
« Reply #77 on: 02/09/2018 02:26 pm »
No direct impact, but FH in many ways cleared the way for BFR, which will have big impact on SLS.

Although just goes by some of the comments in this thread I wonder if even BFR can kill SLS, here's some of the arguments I predict we'll see when BFR flies:
1. BFR and SLS can compliment each other, why can't we have both?
2. BFR can't launch Orion, so SLS is still needed
3. SLS can send 30t+ to TLI in one launch, BFR couldn't, so SLS is superior!
4. No impact to SLS, remember BFR hasn't just come to the scene, it's x years late already...
5. But we have invested so many billions into SLS, it has hardware, we can't just cancel it
6. BFR hasn't demonstrated x number of flights per year, it's still powerpoint!

Now try replacing FH/BFR with Starship Enterprise, and most of the arguments still work, what does this tell you...

That FH/BFR is as real as the Starship Enterprise?

(There's something very Holy Grail logic lesson/witch scene here.)

Offline Robotbeat

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Re: The fate of SLS after Falcon Heavy debut
« Reply #78 on: 02/09/2018 02:41 pm »
You're relying on figures from the KSC ELV performance page, which has figures that are years out of date. For instance, FH can do about 16 tons through trans Mars insertion, which is about c3= 7km^2/s^2 on an *exceptionally* good opportunity. According to KSC's page, FH can only do 10t. So for high energy trajectories, FH can do about 60% better than the KSC page suggests.
No, I didn't use the KSC page.  I have expendable Falcon Heavy at 16.8 tonnes TMI.  SLS Block 1 would be 19+ tonnes, but of course it is only going to fly one trans-lunar mission. For TLI, I show expendable Falcon Heavy at 20+ tonnes and SLS Block 1 at 24.5 tonnes.

The real comparison is with SLS Block 1B, which is expected to be 32 and 39 tonnes to TMI/TLI, respectfully.

 - Ed Kyle
Ah! Good to know.

The real competition is about as far away as BFR is, though.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Scotty

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Re: The fate of SLS after Falcon Heavy debut
« Reply #79 on: 02/09/2018 05:41 pm »
Five years ago, NASA did a study on an Apollo 11 like Lunar mission using two Falcon Heavy launches.
NOTE: That was using the then advertised 53 ton to LEO versions of Falcon Heavy.
The mission would launch the Lunar Lander to orbit around the Moon using the first Falcon Heavy launch. The Orion Spacecraft would launch on the second Falcon Heavy after the Lander was in Lunar orbit. The Orion would make a rendezvous with the Lander, dock, transfer crew. The Lander would then land on the Moon. The Ascent Stage of the Lander would launch off the Lunar surface, rendezvous and dock with Orion. The crew would transfer and use the Orion SM to leave Lunar orbit for an Apollo style Earth reentry and landing.
There also was a option of a Constellation style, two week camping trip on the Moon, using a third Falcon Heavy launch. The third Falcon Heavy would launch first, carrying a Lunar Habitat on the Lander in place of the Ascent stage.
Today's Falcon Heavy has a LEO capacity of 63 tons, making the above even more possible.

Also, SLS Block 1 as planned for EM-1 has the ability to place in excess of 90 tons into LEO.
But the undersized ICPS limits the Lunar throw weight to about 20 tons.
That is why EM-1 will only do a figure eight flyby of the moon (think Apollo 13), or at very best a high Lunar orbit insertion and departure.
ICPS is the Albatross hanging on SLS's neck at this time.

Block 1B with a proper second stage (the EUS), will unlock SLS's capabilities.
Unfortunately, Block 1B is at least 6 years into the future, at very best.

In six years, Falcon Heavy will be in the process of being phased out in favor of BFR.
New Glenn should also be operational by then, with New Armstrong on the horizon.

I doubt we will ever see a Block 2 SLS.
« Last Edit: 02/09/2018 05:43 pm by Scotty »

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