NASA Space Launch System (SLS)

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.
 
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.
 
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.
 
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.
 
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.
 
Last edited:
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.
 
Last edited:
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...
 
Last edited:
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.
 
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.
 
Last edited:
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.
 
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.
 
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.
 
Big news, but it’ll be a while before we know what will actually happen. My guess is many of the cuts will be ignored by Congress.
That’s likely the case—the phase out will probably take until the end of the current administration…but we all guessed that anyway.

That also gives Starship ample opportunity to improve.

Gateway is to have better shielding than ISS modules…might a Starship variant have Gateway in its interior—either permanently, or left behind at one of Mars’ moons?
 
Last edited:
Well Lockheed-Martin has delivered the completed Orion-2 spacecraft to NASA:

Lockheed Martin delivers completed Orion to NASA for Artemis 2

orion-art2-handover.jpeg


WASHINGTON — Lockheed Martin formally delivered to NASA May 1 the Orion spacecraft for Artemis 2, keeping that mission on track for a launch in early 2026.

NASA took acceptance of the Orion spacecraft at the Kennedy Space Center, signing paperwork marking completion of Lockheed’s work to assemble the spacecraft. The spacecraft is now the responsibility of the Exploration Ground Systems (EGS) program.

EGS will now take Orion to processing facilities at the center to load consumables such as propellant, water and oxygen, followed by installation of its launch abort system. Orion will then go to the Vehicle Assembly Building to be integrated with the Space Launch System rocket currently being assembled there.
 
Cancelling SLS and Orion after the Artemis 3, with a replacement architecture yet to be bid, let alone selected and developped, removes a lot of redundancy and backup if anything goes wrong with the hardware of the next 2 missions.

More importantly, the recent budget request confirms what I had thought when I read Isaacman's testimony: There is no lunar ambition anymore, going to the moon is only to "beat the chinese", all the ambition is on mars under this administration, and with gateway and ESM requested to be cancelled, and the few surface collaborations in jeopardy, there is going to be much less of an international anchor to sustain a program through the following administrations

Watching american hearings over the past months it is increasingly clear the US' lunar program is purely reactive to the chinese, the problem is that when your goal is only to strategically check your rival, bringing humans on the loop is an unnecessary burden. in my opinion, the logical conclusion of the current ideology is an abandonment of any permanent or even semi-permanent american crewed presence on the moon to focus on a strategical, semi-military largely uncrewed lunar program focused on strategically checking out the chinese lunar program and ILRS.
 
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.
‘People I have talked to’ is so vague it could mean anything. As Starship’s payload, flight rate, et al. are in flux, it’s premature to assume there is a set plan. There are reasonable cases we can make for LEO-only refueling, HEEO-refueling, and so on, but I have seen little discussion of doing both LEO and HEEO. As far as getting to NRHO, that is a choice versus a limitation of Starship; there are very low-energy trajectories to various orbits near the Moon that come at the cost of time.

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.
So a Starship already in development, then. I think you’re placing too much faith in unverifiable claims that Starship will be refueling in multiple Earth orbits. We don’t need methane or carbon on the Moon, though that would be great - oxygen itself is most of the mass of propellant.

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.
‘Seems to.’ All of the Starship variants have a good deal of commonality between them; development on non-task specific hardware benefits all of them. I have as many doubts about the SLS and Orion as you do of Starship.

Cancelling SLS and Orion after the Artemis 3, with a replacement architecture yet to be bid, let alone selected and developped, removes a lot of redundancy and backup if anything goes wrong with the hardware of the next 2 missions.
The SLS and Orion can’t be backup or redundancy for anything. They don’t have the flight rate, and NASA doesn’t have the budget.

More importantly, the recent budget request confirms what I had thought when I read Isaacman's testimony: There is no lunar ambition anymore, going to the moon is only to "beat the chinese", all the ambition is on mars under this administration, and with gateway and ESM requested to be cancelled, and the few surface collaborations in jeopardy, there is going to be much less of an international anchor to sustain a program through the following administrations
If one assumes that the only efforts that matter are the state’s, perhaps. But it’s primarily Gateway, SLS, and Orion that are in trouble, not CLPS or Artemis as a whole. The American private sector, also, is highly interested in the Moon and raising money. Such an effort will require a reasonable government presence on the Moon, including people.

Watching american hearings over the past months it is increasingly clear the US' lunar program is purely reactive to the chinese, the problem is that when your goal is only to strategically check your rival, bringing humans on the loop is an unnecessary burden. in my opinion, the logical conclusion of the current ideology is an abandonment of any permanent or even semi-permanent american crewed presence on the moon to focus on a strategical, semi-military largely uncrewed lunar program focused on strategically checking out the chinese lunar program and ILRS.
I don’t believe so. A strictly reactive effort would maintain the SLS and Orion, rather than attempting to shift to less expensive, more capable assets.
 
Last edited:
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.
Refueling in a higher orbit requires more flights to bring up the fuel. And you are listening to the wrong people.
 
Refueling in a higher orbit requires more flights to bring up the fuel.
Correct, but it's required in order for Starship HLS to have enough fuel when it reaches the Moon. The process as I understand it is as follows:
  1. SpaceX launches a depot
  2. They then fill the depot up with tanker flights
  3. The depot uses some of its fuel to go to a higher orbit
  4. Starship HLS is launched
  5. It is completely refueled in LEO via tanker flights (based off public statements the total number of tanker flights needed for the entire Starship HLS mission is at least in the low teens)
  6. It then goes to the higher orbit where it meets the depot and refuels again with the remaining fuel in the depot
  7. Starship HLS heads to Lunar orbit
And you are listening to the wrong people.
I am not. These are people that are involved in the program on the NASA side, and what they've told me has matched with the public reporting I've read. If you don't want to believe me, that's fine and totally up to you. But I'm going to stick with sources I trust.
 
I am not. These are people that are involved in the program on the NASA side, and what they've told me has matched with the public reporting I've read. If you don't want to believe me, that's fine and totally up to you. But I'm going to stick with sources I trust.
I can understand the desire to believe them, but on the flip side, I've been blatantly lied to by NASA personnel who theoretically work with SpaceX on Starship (who others have said were trustworthy) regarding both the vehicle and the company, so I retain a healthy dose of skepticism regarding anything they say that hasn't been publicly verified by others.
 
Last edited:
Both Scott Manley and Philip Sloss have videos out concerning this bit of SLS news:


In the latest round of news updates we discuss all the launches, two different crews returning from space, new updates from current space missions and the White House's proposed NASA budget for 2026. Trump takes a page from Obama's space policy and tries to cancel NASA's massive rocket based on the Space Shuttle, will he be successful? Beyond that the NASA budget is the biggest cut in NASA's history, taking huge amounts of money away from NASA's core research.


After a week of high-visibility Artemis II milestones, President Trump and Elon Musk released the skinny budget request for Fiscal Year 2026 on Friday, May 3rd, which made official the long-rumored intent to cancel those Artemis programs and more. In this video, I'll go through the milestones and the initial takeaways from the limited, but key details in the budget request outline.
Now that we have confirmation of the administration's plan, the attention shifts to whether Congress agrees with the Artemis reset. And while we're waiting for that, there's time to start considering all the implications of the new plans. I'll also cover an update to Jared Isaacman's nomination and continuing work on Artemis III SLS hardware, which could be the last to fly.
Imagery is courtesy of NASA, except where noted.
EGS Spacecraft Offline Ops: Getting Orion ready for Artemis II"
Part 1:
https://www.youtube.com/watch?v=a7DaykZLVn8
• How NASA EGS will get Orion ready for... https://www.youtube.com/watch?v=a7DaykZLVn8
Part 2:
• NASA EGS Artemis II launch preps for ...
https://www.youtube.com/watch?v=ccbMc_cOeMg
00:00 Intro
02:08 Lockheed Martin finishes Artemis II Orion assembly, hands spacecraft over to EGS
05:03 Artemis II SLS ICPS stacked after Core Stage engine 4 replacement installed
08:10 Artemis II near-term recap and outlook
09:37 Most Artemis programs terminated in Fiscal Year 2026 budget request
13:28 Boeing moves SLS Core Stage-3 LOX tank to get ready for foam insulation application
15:55 New budget and China race bring more attention to Artemis III program delivery dates
16:20 Will the new commercial Artemis IV be ready to support lunar landing as a backup option?
16:57 Isaacman nomination advances from committee to the full Senate
21:23 Thanks for watching!
Of course pork-barrel politics in the US Congress could of course come to the SLS's rescue.
 
The use of a "secondary propellant transfer" in a "final tanking orbit" for crewed lunar missions in what is essentially a sub-GTO orbit is clearly written in the FCC application for HLS , as well as other sources (I remember seeing it in a NASA Human Exploration & Operations conference)

It may not be always necessary, for example for a demo mission with no payload I am not sure it is necessary, but it certainly exists, it existed in the Starship lunar mission proposals from SpaceX since 2017, and is certainly necessarily (if you do a basic dv calculation) needed to reach the advertised 100t of HLS (not that they'll ever be fully used)

This is not a matter of "source", this is *literally* a plan that exists or at the very least existed at some point. Saying that "there is no point in doing it in higher orbit" is nonsensical.
 
Last edited:
The process is as follows:
  1. SpaceX launches a depot
  2. They then fill the depot up with tanker flights
  3. The depot uses some of its fuel to go to a higher orbit
  4. Starship HLS is launched
  5. It is completely refueled in LEO via tanker flights (based off public statements the total number of tanker flights needed for the entire Starship HLS mission is at least in the low teens)
  6. It then goes to the higher orbit where it meets the depot and refuels again with the remaining fuel in the depot
  7. Starship HLS heads to Lunar orbit
Then clap your hands three times, turn around and touch your nose after patting your stomach and rubbing your scalp while reciting the Gettysburg Address…easy!
 

Similar threads

Back
Top Bottom