What is the best path to a 130 ton (Block II) SLS?

[TomH]

They've discovered oranges on the Moon?  I had not heard that.

Oran ja familiar with Helium3 and polar crater ice?

[Vahe231991]

Although the SLS conducted its first successful launch last November, the first flight of the SLS Block 2 almost certainly won't take place until the early 2030s, but with respect to the question posed by the title of this thread, NASA in May 2018 said that any SLS mission beginning with Artemis 9 would have to require new technology solid rocket boosters given the limited supply of sets of SRBs that utilize components of the SRBs used on the Space Shuttle. Thus, Northrop Grumman has already undertaken design of new-technology SRBs for the Block 2, which remain in the design study phase at the current moment.

Link:
https://www.nasaspaceflight.com/2021/07/sls-bole-srbs/

[spacenut]

The only real path to 130 tons is a 5 engine core, and liquid boosters, with a J2X upper stage.  All of that will cost $billions and with the national debt as high as it is, it is not going to happen.  Reusable liquid boosters would be the best answer, but NASA isn't going to spend the money on their development.

One elephant in the room is development costs with the government debt at an all time high. 

Other elephants in the room are Starship, New Glenn, Neutron, and the existing Falcon Heavy.  All will be able to get tonnage to orbit at a much lower cost.  Even if Starship and New Glenn only recover their boosters, they will be much less expensive than any version of SLS.  Solids are expensive, RS-25's are expensive, RL-10's are expensive, and all are expendable.  SLS is already too late and too expensive.  How many billions will Boeing need to develop reusable side boosters or a decent upper stage that is not too high for the VAB. 

[DanClemmensen]

Best path:
   1) Create a stainless steel nameplate that says "Block 2 SLS".
   2) Weld the nameplate to a SpaceX Starship.
   3) De-rate the Starship from 250 ton (expended) to 130 ton (expended) by removing engines.

[JohnFornaro]

Oran ja familiar with Helium3 and polar crater ice?

Dang.  Bumping this thread from 2013.  SLS has come such a long way from back then.

[Zed_Noir]

Best path:
   1) Create a stainless steel nameplate that says "Block 2 SLS".
   2) Weld the nameplate to a SpaceX Starship Super Heavy.
   3) De-rate the Starship from 250 ton (expended) to 130 ton (expended) by removing engines.

Ahem, the "pseudo SLS Block 2" should be a stock Super Heavy with a shorten 7 engine (6xRVac & 1xRSL) expendable Starship variant 2nd stage and a Centaur X upper stage (dual- engine Centaur V with more propellant tankage).

AIUI the Congressional 130 tonne requirement for the SLS Block II is a minimum payload capacity. The contractor can substitute something more capable, as long as the cost is the same or less.

However the mandate to only use Shuttle derived hardware have to be rescinded and alternate PORK programs being implemented in certain Congressional districts. Before re-branding the Starship stack.

[DanClemmensen]

Best path:
   1) Create a stainless steel nameplate that says "Block 2 SLS".
   2) Weld the nameplate to a SpaceX Starship Super Heavy.
   3) De-rate the Starship from 250 ton (expended) to 130 ton (expended) by removing engines.

Ahem, the "pseudo SLS Block 2" should be a stock Super Heavy with a shorten 7 engine (6xRVac & 1xRSL) expendable Starship variant 2nd stage and a Centaur X upper stage (dual- engine Centaur V with more propellant tankage).

AIUI the Congressional 130 tonne requirement for the SLS Block II is a minimum payload capacity. The contractor can substitute something more capable, as long as the cost is the same or less.

However the mandate to only use Shuttle derived hardware have to be rescinded and alternate PORK programs being implemented in certain Congressional districts. Before re-branding the Starship stack.

I forgot about the shuttle reuse mandate. OK, instead of de-rating the thrust to get down from 250 tonne to 130 tonne, we can load 120 tonne of RS-25s and shuttle SRB segments into the "ballast compartment" to provide the required stability. We don't need to mention that this is political stability, not engineering stability.

[TomH]

Best thing is just to cancel SLS. If you insist on having it, you do it like this with a swap of engines and boosters:

Just replace the RS-25s with J-2X. Also replace the boosters with Super Heavy, not on the sides, but underneath the SLS core which becomes an S2. Now you have the mother of all rockets. (Or, to decrease the price of that, you strip down a SS and stretch it as a throw away and use that as your S2.)

Anyway, the 130 tonne LEO requirement no longer exists. Congress replaced it with a requirement for deep space throw ability.

But enough silliness. This thread should be locked.

[Vahe231991]

Best thing is just to cancel SLS. If you insist on having it, you do it like this with a swap of engines and boosters:

Just replace the RS-25s with J-2X. Also replace the boosters with Super Heavy, not on the sides, but underneath the SLS core which becomes an S2. Now you have the mother of all rockets. (Or, to decrease the price of that, you strip down a SS and stretch it as a throw away and use that as your S2.)

Anyway, the 130 tonne LEO requirement no longer exists. Congress replaced it with a requirement for deep space throw ability.

But enough silliness. This thread should be locked.

I'm not sure why Congress issued the 130 tonne LEO requirement, but the fact that they replaced it with a requirement for deep space throw ability shows that there was a general understanding that the Block 2 variant would be a long way off just as design of the Block 2 was getting underway.

[jstrotha0975]

The best path to a 130 ton SLS is to cancel it and repurpose that money to starship 150 tons.

[Vahe231991]

The best path to a 130 ton SLS is to cancel it and repurpose that money to starship 150 tons.

If the first Starship launch goes well, then NASA is comfortable waiting a few more years to get ready to manufacture components for the first SLS Block 2 rocket in the event that Congress puts potential funding for the SLS Block 2 on hold.

[TomH]

The best path to a 130 ton SLS is to cancel it and repurpose that money to starship 150 tons.

If the first Starship launch goes well, then NASA is comfortable waiting a few more years to get ready to manufacture components for the first SLS Block 2 rocket in the event that Congress puts potential funding for the SLS Block 2 on hold.

Yea, well, you never know what a bunch of politicians are going to do. They are always full of hidden motive.

[spacenut]

Yeah, follow the money to the politicians.