NASA Space Launch System (SLS)

[BlueAbyssal]

As it currently stands, the only crewed version of Starship that will be available in the near term is Starship HLS. And that isn't really useable as a crew transport currently based off the mission architecture and trajectory used to get to lunar orbit. It just takes much too long to get to the Moon and would require doing refueling along the way with crew onboard. It also can't return to Earth, but perhaps using a Dragon to shuttle astros would be possible (it would need two though, Dragon can't loiter in Orbit for the full duration of a lunar mission). Creating some sort of lunar crew transporter from Starship would definitely be possible, but that means money and time to make it happen.

Mission architecture is a choice. As for returning to Earth, not presently, but if we're serious about actually making use of the Moon, we should exploit lunar oxygen as soon as possible, with no non-technical or financial delays because people want to protect their fiefdoms. ISRU benefits everyone, not just SpaceX. SpaceX is already spending the money to turn Starship into a vehicle that can transport people to and from orbit, so that saves NASA money versus another solution.

In the short term the only game in town for sending astronauts to the Moon whether one likes it or not is the SLS.

The short term is effectively Artemis 3. As much as my personal inclination would be to cancel both the SLS and Orion immediately, I can see why people would want at least those to fly. But flying them through Artemis 5, let alone Artemis 10, seems like a recipe primarily for lining the pockets of Boeing and Lockheed's shareholders, and not something done in the interest either of America's citizens or NASA.

 

[NMaude]

But flying them through Artemis 5

I could see Artemis IV and V being launched as the first ages are already in production along with their EUS second-stages, the last RS-25D rocket-motors are on hand for Artemis IV and I do believe the new-build RS-25Es for Artemis V have been manufactured and of course there are the Shuttle SRBs on hand for them.

 

[NCQ]

Mission architecture is a choice.

As it currently stands Starship HLS requires the too long and multi-refuel path to the Moon. It doesn't seem to be a choice. Which makes using it to take crew to lunar orbit challenging. Another version of Starship is likely required, and who know when that's coming.

As for when to kill SLS/Orion, my view is they keep flying until a replacement is actually operational. I don't want to see a gap in capabilities.

 

[NMaude]

As for when to kill SLS/Orion, my view is they keep flying until a replacement is actually operational.

This! The SLS/Orion needs to continue till a replacement is fully tested and ready for operational use.

I don't want to see a gap in capabilities.

The PRC WILL take advantage of gap if it happens.

 

[martinbayer]

A passenger ship named Titanic.
A passenger airship named Hindenburg.
A passenger airplane named Comet.
A passenger car named Pinto.
A passenger launch vehicle named Space Shuttle.
I am absolutely convinced that the Space Shuttle derivative Space Launch System/Orion spacecraft combination will be perfectly fine.

 

[NMaude]

I am absolutely convinced that the Space Shuttle derivative Space Launch System/Orion spacecraft combination will be perfectly fine.

Unlike the Space Shuttle the SLS has a functioning LAS along with not using fragile silica tiles for a heat shield and its' SRBs don't have faulty O-rings.

 

[martinbayer]

Unlike the Space Shuttle the SLS has a functioning LAS along with not using fragile silica tiles for a heat shield and its' SRBs don't have faulty O-rings.

LAS could fail as well - *no* engineered system is ever absolutely, utterly, completely, infallible, and as an aerospace engineer it pains me to admit to this inherent weakness of our craft. No matter how deep you dive into *Fail Safe* levels, the next unexplored level down might just get you. But, as a former conceptual launch vehicle designer I'll cut to the quick: Stupid (as in uncontrollable) solids like on SLS are the devil's fireworks, and I really had hoped the Challenger accident would have drilled that into the US/NASA design community, but apparently no dice...

 

[BlueAbyssal]

As it currently stands Starship HLS requires the too long and multi-refuel path to the Moon. It doesn't seem to be a choice. Which makes using it to take crew to lunar orbit challenging. Another version of Starship is likely required, and who know when that's coming.

As for when to kill SLS/Orion, my view is they keep flying until a replacement is actually operational. I don't want to see a gap in capabilities.

You should define your terms. What does 'too long' mean? A few days? A week? A month? Are you counting the time it takes to refuel a depot and then fill up the lander? If so, why? What other versions are necessary other than the ones presently under development?

I would rather have a temporary gap in capabilities, and see much less money appropriated from taxpayers' pockets, than to continue to fly the SLS and Orion and accomplish very little while spending billions yearly. We could repeat Apollo 8 over and over, or let the astronauts enjoy the radiation environment of NRHO while doing largely meaningless experiments, but neither of those is worth the expenditure of all those careers, the skills of the workforce, the time, or the money.

This! The SLS/Orion needs to continue till a replacement is fully tested and ready for operational use.

This sounds reasonable if one assumes the SLS can fly frequently (>1 flight/year), cheaply (<$1 billion marginal cost/flight), and that there are no alternatives in the near term (<5 year) horizon. But none of those are true. The SLS program will be lucky if, on its own merits, with no reference to any outside programs, it flies three more times this decade.

The PRC WILL take advantage of gap if it happens.

It's short-term prestige thinking like this that led to an unsustainable approach with Apollo, and its subsequent cancelation.

LAS could fail as well - *no* engineered system is ever absolutely, utterly, completely, infallible, and as an aerospace engineer it pains me to admit to this inherent weakness of our craft.

So few people ever admit that launch abort systems can have issues too. Vielen dank.

 

[NCQ]

You should define your terms. What does 'too long' mean? A few days? A week? A month? Are you counting the time it takes to refuel a depot and then fill up the lander? If so, why? What other versions are necessary other than the ones presently under development?

My current understanding, based off people I have talked to involved in HLS on the NASA side as well as reporting on HLS, is that Starship HLS is refueled twice on the way to the Moon. It is refueled in LEO after launch, then uses that fuel to get into a higher Earth orbit where it docks with another tanker and refuels again, at which point it then goes to Lunar orbit. The tankers can be pre-positioned, but even then the flight profile will take somewhere on the order of weeks to get into Lunar orbit. If you are using Starship HLS to get back from Lunar orbit you will also need to do this in reverse, though it may be possible to use some sort of aerobraking to reduce the refuels needed if Starship HLS is capable of it.

A Starship version needed for crew transport is probably one that can get from a fully refueled state in LEO to Lunar orbit (probably NRHO would be a good option, it's a great orbit for lunar ops in general and has lower delta-v requirements) and back to LEO without having to stop along the way during transit between the Moon and Earth to refuel. Designing for aerobraking would make things much easier. And if methalox ISRU is practical on the Moon, investing in that capability would also be benefitial to refuel while in Lunar orbit.

I do want to emphasize though that Starship HLS is currently the only crewed version of Starship that seems to have significant development ongoing. We've seen renders of other crewed versions, and SpaceX says they will do it, but thus far we haven't seen any significant work on it. And I do believe they will make a crewed Starship eventually, just that it doesn't seem like it's coming soon. Even with Starship HLS there are a lot of doubts about it (and the stuff it needs to get to the Moon) being ready in time for AIII in 2028.

 

[Byeman]

My current understanding, based off people I have talked to involved in HLS on the NASA side as well as reporting on HLS, is that Starship HLS is refueled twice on the way to the Moon. It is refueled in LEO after launch, then uses that fuel to get into a higher Earth orbit where it docks with another tanker and refuels again, at which point it then goes to Lunar orbit. The tankers can be pre-positioned, but even then the flight profile will take somewhere on the order of weeks to get into Lunar orbit. If you are using Starship HLS to get back from Lunar orbit you will also need to do this in reverse, though it may be possible to use some sort of aerobraking to reduce the refuels needed if Starship HLS is capable of it.

No, it is only refuel in LEO (and it is multiple times). There is no point in doing it in a higher orbit.

 

[Byeman]

As it currently stands Starship HLS requires the too long and multi-refuel path to the Moon. It doesn't seem to be a choice. Which makes using it to take crew to lunar orbit challenging. Another version of Starship is likely required, and who know when that's coming.

As for when to kill SLS/Orion, my view is they keep flying until a replacement is actually operational. I don't want to see a gap in capabilities.

There is no point to keeping SLS since it use Starship HLS. Taking crew to lunar orbit is easy.

 

[NCQ]

No, it is only refuel in LEO (and it is multiple times). There is no point in doing it in a higher orbit.

That is not correct both from what I have hard directly from people involved in the program and the reporting I have read. There is a point in refueling in a higher orbit as it allows you to have more fuel when you reach the moon.