Space Launch System: Preliminary Design Review

[czokletmuss]

I still wonder - will it be canceled or not?

[Themohawkninja]

It's entirely possible that it could be canceled, as many programs get to a certain point in development and testing, and then they get canceled for money/safety/performance reasons.

[metaphor]

I don't think it will be cancelled anytime soon. It has a lot of supporters in Congress since it gives jobs to people in their districts, especially former Shuttle employees. If the budget goes down, they will rather cut the rest of NASA before they cut the SLS. Also, it's already further along than the Constellation program, and it doesn't have any red flags on technical/cost/schedule issues like the Constellation program did.

But those same people in Congress who support it don't really care how often it flies, as long as the people in their district keep their jobs. So the major problem now is funding payloads for it and making sure there's destinations for it to fly to more than once every few years.

It's a pretty sure bet that we will develop the SLS. Whether we will use it to its full extent afterwards is the question to ask.

[Albert VDS]

With each year of budget cuts for NASA, I doubt that once the SLS is done it will go anywhere besides the ISS.

Way before the SLS is done, SpaceX will have their Dragon Rider(on a F9) operational and only 160 million per launch opposed to 500 million(the cheapest estimate) for SLS/Orion.

Not to mention when SpaceX manages to make the F9 reusable.

It would be better for NASA to spend their money on their missions, not reinventing the rocket.

I say pay SpaceX for their launches, which enables them build the successor for the F9(H).

[metaphor]

With each year of budget cuts for NASA, I doubt that once the SLS is done it will go anywhere besides the ISS.

Way before the SLS is done, SpaceX will have their Dragon Rider(on a F9) operational and only 160 million per launch opposed to 500 million(the cheapest estimate) for SLS/Orion.

Not to mention when SpaceX manages to make the F9 reusable.

It would be better for NASA to spend their money on their missions, not reinventing the rocket.

I say pay SpaceX for their launches, which enables them build the successor for the F9(H).

SLS is not designed to go to the ISS. It might be a backup option, but the SLS is way too overpowered for just going to the ISS.

The SLS should only be used for beyond-LEO missions. That's why NASA is funding SpaceX and the other commercial crew competitors, to develop vehicles to send people up to the ISS and back. The Dragon Rider might be 160 million per launch but it can't go beyond LEO. Even the Falcon Heavy can only get about 15 tons to TLI (trans-lunar injection), while the earliest form of the SLS can get ~30 tons to TLI.

SLS/Orion and Falcon/Dragon Rider are just designed for different missions, so you can't really compare them.

[czokletmuss]

Wait, the SLS is a heavy lifter, right? NASA isn't planning to use this giant rocket to send tiny Orion to ISS, is it? 'Cause it has no economical justification.

[Tiberion]

No, they are not planning on sending it to the ISS. That is why they have the commerical crew dev project - one or two of the projects will be contracted to do the crew delivery for NASA. (Thats Dragon Rider, the DramChaser shuttle, and the CST-100 pod by Boeing and Bigelow)

Dreamchaser and CST-100 will be launched by Atlas V (once it is man-rated.)

[Albert VDS]

I know that the SLS is meant to take us farther than LEO, once it's completed it's a very capable vehicle.

But that's not the problem I pointed out, the problem is NASA's budget which seems like a toy to politicians.

And then their matter of it being spread over many projects.

This isn't a bad thing per say, it keeps them in business, but there's only so much to go around.

How are you gonna pay for a Moon mission if you don't have the money?

And then there's change of administrations every 4 years, 8 if your are lucky/unlucky(depending who's in charge).

So more chance of cancellation and budget cuts.

Companies like SpaceX exist to make money by building rockets, their goal is much clearer.

[Kerbface]

I think the SLS could end up going to the ISS or another space station, just so long as it has a seriously big module to add.

[bigdad84]

I really wish they would of kept the Constellation project going. Ares I and Ares V.... Still capable of going to the ISS also. I have always thought since the beginning, that launching astronauts and cargo together is a bad idea...

[metaphor]

I really wish they would of kept the Constellation project going. Ares I and Ares V.... Still capable of going to the ISS also. I have always thought since the beginning, that launching astronauts and cargo together is a bad idea...

The Constellation program ran into a lot of technical/cost/schedule problems before it even got to the stage where SLS is now. There were also some safety problems with using a single SRB as the first stage of a crewed flight. But the SLS, at least the later version, is pretty much the same design as the Ares V with its big cargo capacity. If we ever have a mission to beyond the Moon that requires assembly in Earth orbit, most of the flights are going to be cargo flights except for the last one with crew aboard.

[czokletmuss]

I guess in this case the last one will be on board the Dragon rather than SLS (cheaper).

[deadshot462]

This won't be cancelled, no administration wants to be blamed for putting a ton of people out of work. Congress will just keep giving it a steady fund, a "goal" of going to an asteroid, more testing, and maybe a launch.

[rdfox]

The Senate Launch System won't be cancelled, it has too much support on Capitol Hill. However, I doubt we'll see more than four or five total launches of it, as there just isn't that much demand for the ability to put a locomotive into low Earth orbit.

I suspect NASA knows this, too, and that's why they plan on using the ex-Shuttle RS-68 engines in the first stage instead of J-2X's or some other designed-as-expendable engine--they only have enough RS-68s for about five launches without having to start building new ones, but they figure they'll never NEED to build new ones for it because it's just too big to be practical.

[metaphor]

The Senate Launch System won't be cancelled, it has too much support on Capitol Hill. However, I doubt we'll see more than four or five total launches of it, as there just isn't that much demand for the ability to put a locomotive into low Earth orbit.

I suspect NASA knows this, too, and that's why they plan on using the ex-Shuttle RS-68 engines in the first stage instead of J-2X's or some other designed-as-expendable engine--they only have enough RS-68s for about five launches without having to start building new ones, but they figure they'll never NEED to build new ones for it because it's just too big to be practical.

RS-68 are the engines used on the Delta-IV. The Space Shuttle main engines are RS-25D. RS-68s were considered for the SLS as an alternative to the RS-25D. But since NASA already owns quite a few spare RS-25Ds (and they are also more efficient than RS-68s), they decided to use those instead, and make cheaper expendable versions of them once they need more. Engines are one of the most expensive components of a spacecraft so it would make sense to use an existing stock of engines to lower costs at first. It takes a very long time to design, test, and build new engines. (J2-X are the engines to be used on the second stage of the SLS.)

The reason there isn't much demand to put a lot of mass into LEO at once is that we haven't made that demand yet. If we ever decide to take crewed spacecraft beyond LEO, that would generate the demand for heavy-lift rockets. That's why we have to make sure Congress gives the SLS funding for payloads and missions.