SLS Shuttle

[clivman]

and the ISS is very inclined...

Please stop necro-posting

[G'th]

(Its only necromancy if you aren't actually contributing to the topic at hand. Just because teh topic started a year ago doesn't mean we can't pick it back up and start talking about it

6 Pages over a year and no one mentions the Saturn-Shuttle concept

The basic idea being that the S-IC stage of the Saturn V replaces the ET/Booster stack of the flown Shuttle. Wouldn't be too terribly hard to convert SLS to this concept, but its ultimately something that would have had to have happened early in the Shuttle program.

[Frozen_Heart]

Wow you guys dug this one up. I made this thread a year ago! (new profile)

And yeah I've long since come to the conclusion that the whole thing would be a bad idea. If you want to shift cargo up then the standard SLS would do. Just crew and a Dream chaser would work. Making every cargo flight need crew is a bad idea.

Then again imo the whole SLS is a poor idea in the first place...

[G'th]

Wow you guys dug this one up. I made this thread a year ago! (new profile)

And yeah I've long since come to the conclusion that the whole thing would be a bad idea. If you want to shift cargo up then the standard SLS would do. Just crew and a Dream chaser would work. Making every cargo flight need crew is a bad idea.

Then again imo the whole SLS is a poor idea in the first place...

Technically the SLS would be overkill for ISS resupply. For a newer, bigger space station or may be a Lunar base, sure, the SLS would do fine. But for an ISS sized station, the SLS is wayy overkill, namely because the Block 1 SLS is going to be capable of sending something on a circumlunar trajectory, so using the SLS for LEO missions (particularly if that ends up being what its used for mostly) would be a huge waste outside of basic testing.

Even the shuttle is more appropriate for it, and it has that added benefit of being able to bring mass back down intact.

[jwenting]

Best thing for an STS replacement would be to revive Venturestar... It was actually designed to do what the STS promised but never delivered: increase launch frequency and reduce cost per pound to orbit.

And as a result it was killed, the NASA army of useless managers that grew up around the STS couldn't cope with a new system that'd show they were just leeching vast amounts of money.

Sure the prototype was late and over budget, but the timeframe set to construct it was overly optimistic and as a result the budget deliberately very low.

[Pipcard]

Venturestar was cancelled because it suffered from various technical problems in trying to make the dry mass fraction (especially the hydrogen tank) efficient enough.

[Frozen_Heart]

Venturestar was cancelled because it suffered from various technical problems in trying to make the dry mass fraction (especially the hydrogen tank) efficient enough.

It was the fuel tanks that they were struggling with. The engineers did come up with a solution to make them light enough but it was pretty much cancelled by then. Today there are much lighter materials that could be used.

[okan170]

It was the fuel tanks that they were struggling with. The engineers did come up with a solution to make them light enough but it was pretty much cancelled by then. Today there are much lighter materials that could be used.

The big thing with this is, while the tank would have flown and worked on X-33, it would not have worked for Venturestar which had to be SSTO. Part of the whole reason X-33 existed was as a testbed for the Venturestar SSTO technologies, and one of these was the composite tank. X-33 could've achieved it's modest hypersonic goals with the aluminum tank, but Venturestar could not make orbit with it. X-33 had little to no application outside of being a tech demonstrator

Venturestar/X-33 were joined at the hip somewhat unusually and it bit them hard in the end. Traditionally, one would design the final vehicle after the sub scale demonstrator… but X-33 was designed to specifically enable Venturestar (which had certain specifications), and when the performance started to creep out of feasibility, losing one meant losing the other. It doesn't help that Venturestar was the SSTO design that had the most unknowns about it compared to a selection of options from other manufacturers. Around the same time X-33 ran into issues with it's tank, Venturestar was running up against increasing weight in the aerospikes (far heavier and less efficient than had been anticipated) and a need for a significantly beefier TPS to deal with the heat loads of reentry and much larger wings in order to remain in control during atmospheric entry. It had ballooned into a huge behemoth with very large wings, much heavier tile coverage and heavy engines, when the tank issues started coming up.

This is a good example of what Venturestar had become by the time it was cancelled.

By the end of it all, Venturestar was no longer capable of achieving it's SSTO goal and was cancelled along with X-33. The tanks could certainly be done better today, but there are also a large number of problems to solve with the design.