SLS or Constellation?

[Giggleplex777]

Which program do you think is better?

[czokletmuss]

Shouldn't there be third option like "both aren't very good ideas" or smth like that?

[metaphor]

They're both pretty much the same in terms of the rocket. The only different thing about them is the destination, one is to the Moon and the other is to asteroids and Mars.

[Giggleplex777]

Shouldn't there be third option like "both aren't very good ideas" or smth like that?

Too late now.

[Rune]

Considering SLS is Ares V+Orion without Altair and the rest of the stuff, and both are going to end up doing nothing for lack of funding, I'd say none of the answers are applicable. Both are paper exploration programs that won't get anywhere.

Rune. 20% of NASA's budget, directly going to pork with nothing to show for at the end. Sad.

[czokletmuss]

I think that the proposed asteroid mission:

is a better goal than practically reacting the Apollo program with the better equipment:

But the Orion spacecraft - the first deep space manned vessel - is the only valuable thing in the SLS I'm afraid.

[Canopus]

Its not like SLS wouldn't be used to get to the moon. Read this article:http://www.nasaspaceflight.com/2013/01/boeing-discusses-sls-robust-lunar-program/ But the best thing about SLS is the proposed L2 station called "Exploration Gateway Platform":http://www.nasaspaceflight.com/2011/12/exploration-gateway-platform-hosting-reusable-lunar-lander-proposed/

[BossSquirrelz]

Considering SLS hasn't been canceled yet, and Orion is set for a test flight next year, followed by a full SLS test in 2017.

[Rune]

And what happens when 2021 passes by, and no more payloads are available for the giant rocket? If it actually gets that far, that is. The whole aerospace community is pretty much dead-set against it, except the people that work at building it, which are grasping at straws to sell it at this point. Where is the money coming from for the L2 gateway? Where would you get the money from, to build the lunar lander? Does someone seriously think that at a projected 500 million a pop (at least, it'll probably cost-overrun considerably more), it is actually sustainable in any way? And most important of all... why is it needed to lift Orion, if Orion is going to be test-flown on a Delta at a fraction of the cost? Always consider NASA's budget hasn't gone up since Apollo. It really makes no sense, unless you look at it from a pork perspective, then it's the best business ever.

Also, Orion has as much use as a deep-space vessel as a Soyuz, or a manned Dragon, or the old Apollo command module. Which is, basically, a decent heatshield for a return that assumes you throw away the rest of your exploration vessel after each flight. No room, no radiation protection, no long-term supplies, no significant delta-v on its own. Pretty thin to sell it as a "deep-space exploration vessel". And it's already costed what, 5 billion give or take? I think I'm on the low side on that, actually. It's verging on the absurd, but I'm sure Lockheed is happy to keep at it. If Congress wanted NASA to get somewhere, they wouldn't have cancelled, and actually forbidden by law to pursue, the only deep-space thingies that were once in the works, namely Transhab (yeah, it's illegal for NASA to build deep-space habs!) and NERVA.

Rune. Sorry to rain on your parade.

[brooksy125]

Both are people throwing money at something and expecting something good to happen,

They should have used the money to do something useful like revamp the space shuttles rather than scrapping them.

[czokletmuss]

This is test flight:

But if you want to send some big payload to Mars or its moons you need something bigger then Delta. I'm not supporting the SLS (not that it matters since I'm not even US citizen) but with rocket that big there will be a possibility of sending really heavy equipment on orbit, which will enable (I hope) some serious orbital constructing like this which is needed for the Nautilus X or other big ships. And yes, NASA should concentrate on NERVA or VASIMR-like engines if we're ever going to leave the Earth-Moon system.

[NASAFanboy]

I wanna moonbase, so its Constellation. Everything else for Constellation can go.

[metaphor]

If the SLS costs $500 million per flight, that would be about 5 times more cost-efficient at putting mass into low Earth orbit than the Space Shuttle, and it would be about the same cost per mass as the Falcon 9 currently has. Bigger rockets are generally more efficient, it's just that there's not much use for them in the commercial sector since satellites tend to be small. We need a heavy-lift rocket to go anywhere outside of low Earth orbit, which the SLS would be very useful at even if it is plagued by inefficiency and congressional indecisiveness. With the Congress the way it is now, if the SLS gets cancelled, nothing will replace it and the money will go away.

[Netris]

I thought Constellation was cancelled by Obama in 2010

[deadshot462]

Constellation. An actual goal of a moon landing was great, unfortunate it went over budget and behind schedule.

[EKS21]

Constellation is just the series of vehicles used in the SLS. They will be used for other purposes, but Constellation is pretty much, just the SLS.

[Rune]

If the SLS costs $500 million per flight, that would be about 5 times more cost-efficient at putting mass into low Earth orbit than the Space Shuttle, and it would be about the same cost per mass as the Falcon 9 currently has. Bigger rockets are generally more efficient, it's just that there's not much use for them in the commercial sector since satellites tend to be small. We need a heavy-lift rocket to go anywhere outside of low Earth orbit, which the SLS would be very useful at even if it is plagued by inefficiency and congressional indecisiveness. With the Congress the way it is now, if the SLS gets cancelled, nothing will replace it and the money will go away.

Let's run those numbers again. Assuming they actually reach the goal of 500 million a flight (I don't believe that, but its what they say), we get 70mT on low orbit at 7.1 million/mT. You compare with shuttle, and indeed you are right, since the best cost analysis I've seen on it (at least in order of magnitude, shuttle accounting is a mess) got a similar cost per flight, and the payload was roughly a third, so it is more effective... unless you take into account that the whole ~70mT orbiter got to orbit with its ~25mT payload.

But then you go and compare with Falcon Heavy. Which is announced to cost 125 million to the customer, and you could book right now. They wouldn't charge you for development, they wouldn't charge you to "maintain the capabilities", or to build a new launch pad/construction tools/crawler/whatever they can get away with. And it clocks in at 53mT to 200km LEO circular, which comes out to 2.35 million/mT, or a third of the cost for 2/3rds of the payload. Any, I repeat, any ELV can do better than SLS in cost per kilogram to orbit, even the incredibly expensive Delta IV. Which is really, really strange, since as you said bigger rockets should be much more efficient in those terms. And that is believing the cost projections as they stand right now, which is really hopeful thinking IMO.

My conclusion? Someone should prosecute the contractors for fraud. They are robbing you blind.

Rune. Once, a long time ago, I was actually looking forward to Ares V. Then I learned better.

Edited April 20, 2013 by Rune

[Nibb31]

Constellation:

- Pros: At least it had focus and a clear mission. Return to the Moon, establish a base.

- Cons: The Ares I launcher was stupid and didn't work. It under-delivered and couldn't have been able to launch a real Orion into orbit. It's only reason to exist was to keep ATK Thiokol in business.

SLS

- Pros: It's big and capable

- Cons: It has no mission yet. With such a low launch rate, it will be way too expensive.

I think NASA is doing what it can on a shoestring budget, hoping that once they have the rocket, Congress will give them a mission to use it. Ideally you should first agree on a mission, and then design your hardware for that mission.

I'm pretty sure that SLS will launch 2 or 3 missions, maybe manned, and end up being cancelled because it will have a huge annual cost for one launch every 1 or 2 years and no budget for actual mission modules.

[Nibb31]

Constellation is just the series of vehicles used in the SLS. They will be used for other purposes, but Constellation is pretty much, just the SLS.

Nope.

Constellation was Ares I, Ares V, Orion and Antares. Ares V and Antares were really just case studies with no development budget. Ares I was over-budget and under-performing. Only Orion was a good design, but suffered a lot from Ares I's shortcomings.

SLS is more like the Direct project, which was an alternative study that was run on the sides by NASA folks who were unhappy with the Ares launchers.

[Kryten]

I think NASA is simply banking in there being majorly improved economic conditions by the time SLS actually needs payloads, in which case the viability depends on whether this actually happens. I'm no economist, but the prospects of that aren't looking particularly good.

[Nibb31]

If the SLS costs $500 million per flight, that would be about 5 times more cost-efficient at putting mass into low Earth orbit than the Space Shuttle, and it would be about the same cost per mass as the Falcon 9 currently has. Bigger rockets are generally more efficient, it's just that there's not much use for them in the commercial sector since satellites tend to be small. We need a heavy-lift rocket to go anywhere outside of low Earth orbit, which the SLS would be very useful at even if it is plagued by inefficiency and congressional indecisiveness. With the Congress the way it is now, if the SLS gets cancelled, nothing will replace it and the money will go away.

When you have such a low flight rate, the cost of the actual launch is irrelevant. There will be no economies of scale because it will only launch every 1 or 2 years. The bulk of the cost will be maintaining the facilities and the personnel. These are fixed costs that you have to pay, whether you launch or not.

After a several billion dollars paid for only one or two flights, it will probably get cancelled.

[Rune]

Nope.

Constellation was Ares I, Ares V, Orion and Antares. Ares V and Antares were really just case studies with no development budget. Ares I was over-budget and under-performing. Only Orion was a good design, but suffered a lot from Ares I's shortcomings.

SLS is more like the Direct project, which was an alternative study that was run on the sides by NASA folks who were unhappy with the Ares launchers.

You mean Altair, right? The H2/LOX lunar lander that could do polar missions? Just nitpicking, don't mind me.

[Nibb31]

Yeah, sorry, Altair of course !

[czokletmuss]

Even if it will be cancelled NASA will have the know-how, blueprints and personel capable of building such a huge rocket. Read this article about quest to recover the Saturn V engine http://arstechnica.com/science/2013/01/saturn-v-moon-rocket-engine-firing-again-after-40-years-sort-of/

Plus there is a small possibility that with a LEO payload that big the next space station or the first spacecraft assembled on orbit won't take years like the ISS did.

[Rune]

Even if it will be cancelled NASA will have the know-how, blueprints and personel capable of building such a huge rocket. Read this article about quest to recover the Saturn V engine http://arstechnica.com/science/2013/01/saturn-v-moon-rocket-engine-firing-again-after-40-years-sort-of/

Plus there is a small possibility that with a LEO payload that big the next space station or the first spacecraft assembled on orbit won't take years like the ISS did.

Well, it is a really good way to keep a lot of aerospace contractors happily working, I can't deny that. That is short of what I have been saying all along. But I would much prefer to have them working at something worthwhile. Imagine if the money was spent on building in-space reusable (hence, refuelable) stages and putting them on top of rockets (chemical or nuclear, for a near-term personal proposal, I would like to see a methane/LOX transfer stage/unmanned tug). Or fuel depots, or transfer habitats, or multipurpose reusable landers, or waypoint stations, or surface habitats... we could have an inner solar system transportation system set up for what this program will cost, and we would end up going somewhere, while those aerospace contractors keep receiving their paychecks just like they do now.

The only big advantage SLS could have over other launch systems is the 10m diameter of the core stage. And Boeing keeps on showing stuff that throws that away by inserting a 5m adapter, and other people finding neat tricks to get around the launch diameter limitations in the meantime (inflatable heatshields, segmented mirrors, that short of thing). That means they throw that away and look even more silly next to the Falcon heavy, or even ULA's own launchers. Hell, even old Proton can do what SLS is meant to do, cheaper, if you master the crucial in-space techniques like autonomous rendezvous and fuel transfer that we would need anyway. Right now this looks like the old NASA fixation on direct return from the moon and huge Nova rockets. Remember what Churchill said? "You can always trust the Americans to do the right thing... after they have tried out every other possibility and seen that they don't work". When is NASA going to do the equivalent of the "go with LOR" decision, and how much money will they burn in the meantime?

Rune. Lots of things to do, and practically none getting done.