With which upper stage will Artemis IV fly?

[dglow]

Question originally raised in the SLS Discussion Thread.

ULA’s Tory Bruno confirmed that ICPS production capacity continues to exist. This is notable as ULA has built their final, planned ICPS, which is intended for Artemis III.

The question: Will Artemis IV fly as planned, launching from ML2 and sporting the new EUS? Or will NASA fall back to Block 1 for this mission and choose to make further use of ULA’s production line?

Your predictions above, please.

[deltaV]

This poll is missing 2/3rds of the options:
* SLS with another upper stage
* SLS with no upper stage
* Another launcher
* Artemis IV doesn't happen at all

[whitelancer64]

NASA should order another ICPS. I don't think they will, though. They'll press on with EUS regardless of delays to Artemis IV.

[Zed_Noir]

This poll is missing 2/3rds of the options:
* SLS with another upper stage
* SLS with no upper stage
* Another laucher
* Artemis IV doesn't happen at all

NASA don't have the budget and time to developed and certified another upper stage for the SLS. Of which there is only one near term candidate. The more capable but unflowned Centaur V upper stage.

The SLS without the upper stage can only get to LEO with substantial payload reduction. The RS-25 can not re-lighted away from pad GSE.

The Congressional critter wouldn't allow Artemis IV to move to the other alternate launcher or stop funding the SLS/EUS/Orion hardware.

NASA should order another ICPS. I don't think they will, though. They'll press on with EUS regardless of delays to Artemis IV.

In which case, the SLS for Artemis IV will likely become a display somewhere. Don't expect Boeing to get the EUS stage online by 2032 at the earliest.

[yg1968]

In which case, the SLS for Artemis IV will likely become a display somewhere. Don't expect Boeing to get the EUS stage online by 2032 at the earliest.

Is EUS or ML2 the long pole?

Looking for articles on this subject, I came across this paid-advertisement from Boeing:

Exploration Upper Stage Unveiled: Revolutionary Leap in Crew Safety, Cargo Capacity, and Deep Space Power:
https://spacenews.com/exploration-upper-stage-unveiled-revolutionary-leap-in-crew-safety-cargo-capacity-and-deep-space-power/

[dglow]

Exploration Upper Stage Unveiled: Revolutionary Leap in Crew Safety, Cargo Capacity, and Deep Space Power:

‘Leap in Crew Safety’… okay then. Remind me, which part of that leap calls for carrying crew without a test flight?

[yg1968]

Exploration Upper Stage Unveiled: Revolutionary Leap in Crew Safety, Cargo Capacity, and Deep Space Power:

‘Leap in Crew Safety’… okay then. Remind me, which part of that leap calls for carrying crew without a test flight?

Yes, I agree. I just posted this because it shows how Boeing advertises the benefits of the EUS. This advertisement is obviously a form of lobbying but a lot of the advertised capabilities will likely never be used. For example, it says that EUS increases the amount of payload to the Moon (see the quote below). That is a capability that will never be used as the HLS providers will bring the payload themselves (e.g., the habitat or the pressurized rover) to the surface of the Moon without using SLS. However, EUS and Orion will be used in order to get Gateway modules to NRHO.

The EUS will replace the Interim Cryogenic Propulsion Stage (ICPS), which is currently used on the Block 1 configuration of the SLS rocket, allowing NASA to send astronauts and large payloads to the Moon on a single mission. Compared to the single-engine ICPS, the EUS has larger propellant tanks and four RL10 engines. EUS provides 97,000 pounds of thrust during translunar injection versus nearly 25,000 pounds of thrust from ICPS. This added boost allows for 40 percent more payload to be sent to the Moon and beyond, enabling NASA to send more than 83,000 pounds of cargo on a single crewed mission. That means not only can the EUS send a crew to the Moon and around the Moon, but it will also be able to haul cargo such as small lunar habitats or scientific experiments in the same launch.

[VSECOTSPE]

Don't expect Boeing to get the EUS stage online by 2032 at the earliest.

Where’s that year come from?

Thx in advance.

[Zed_Noir]

Don't expect Boeing to get the EUS stage online by 2032 at the earliest.

Where’s that year come from?

Thx in advance.

Past the next two US federal election cycles.

[dglow]

Don't expect Boeing to get the EUS stage online by 2032 at the earliest.

Where’s that year come from?

Thx in advance.

Past the next two US federal election cycles.

What is the logic behind two? Both likely presidential candidates are up for a final term, and both support(ed) Artemis. Please explain.

[Robotbeat]

Exploration Upper Stage Unveiled: Revolutionary Leap in Crew Safety, Cargo Capacity, and Deep Space Power:

‘Leap in Crew Safety’… okay then. Remind me, which part of that leap calls for carrying crew without a test flight?

That’s the “leap” part. They didn’t say which direction the leap was…

[Zed_Noir]

Don't expect Boeing to get the EUS stage online by 2032 at the earliest.

Where’s that year come from?

Thx in advance.

Past the next two US federal election cycles.

What is the logic behind two? Both likely presidential candidates are up for a final term, and both support(ed) Artemis. Please explain.

Nothing to do with future POTUS and their support for the Artemis program. It is the future NASA administrator appointments and how much they can revamped the upper NASA management to get things done.

Whomever is the administrator after senator Nelson will have too any issues to deal with to be other than a caretaker, IMO.

The one after the next administrator will have to make hard decisions on NASA upper level management. Since I fully expect the various parts of the Artemis program to be behind schedule, including the EUS.

Hopefully Boeing should be able delivered a flightworthy EUS by 2032 after the management shakeup.

The convoluted reasoning for my previous posts for your edification.

[DanClemmensen]

Upper stage will be SS, booster will be SH, because Congress will finally realize SLS/Orion is unsustainable based on the recent GAO report and mandate that NASA open a bid for a commercial transportation service. SpaceX will submit the only credible bid because of the time constraint.

[russianhalo117]

Question originally raised in the SLS Discussion Thread.

ULA’s Tory Bruno confirmed that ICPS production capacity continues to exist. This is notable as ULA has built their final, planned ICPS, which is intended for Artemis III.

The question: Will Artemis IV fly as planned, launching from ML2 and sporting the new EUS? Or will NASA fall back to Block 1 for this mission and choose to make further use of ULA’s production line?

Your predictions above, please.

DCSS5 production tooling will if needed move to MAF now that ICPS-3 and the last DCSS5 on the backlog have shipped. It is in the process of being mothballed for storage.

[Proponent]

Voted ICPS. My thinking us that the primary purpose of SLS is to funnel public money to certain congressional districts (witness the nearly complete lack of Congressional complaint about its absurdly expensive and stretched out development, highlighted yet again recently by yet another damning FAO report). That purpose is best served by endless development. Hence, EUS will slip and slip, just as the rest of SLS has.

[jadebenn]

NASA should order another ICPS. I don't think they will, though. They'll press on with EUS regardless of delays to Artemis IV.

There is a case to be made for ICPS, but I'm of the opinion that it's a case that would've needed to be made quite a bit earlier.

I know Tory has stated the DCSS/ICPS tooling is still there, just mothballed, and I see no reason to doubt he's telling the truth... but I also suspect that he's somewhat overselling how easy and painless it would be to reverse course on that decision at this point. After all, ICPS is a contract with ULA: EUS is a contract with Boeing.

Anyway, I voted EUS for a few reasons, but mainly that we'd need to be seeing moves toward ICPS right now for Artemis IV, and that's simply not what I'm seeing.

EDIT: Also, if russianhalo117 is right about NASA taking ownership of the ICPS tooling and shipping it to MAF, that would imply new ICPS production would require training an entirely new workforce to build ICPS instead of using the (already decaying) ULA experience. It doesn't take long to get "out of practice" building these things as-is, but shipping it off to a new facility with new staff certainly wouldn't help. Why wouldn't NASA continue training the MAF workforce on the EUS tooling instead? They've already started.

[JEF_300]

I voted ICPS. I'm not sure that I necessarily should've, because I agree that restarting ICPS production seems difficult, but the idea that the EUS and it's MLP will be ready before 2028 seems just as or more suspect to me.

And frankly, I'm not sure what Congress gets out of the EUS. SLS block 1 is enough for NASA to get by, and enough to fulfill any theoretical national security requirements, and Boeing already has it's bone with the core stage. Is it really just about the contract cancellation fees?

[TheRadicalModerate]

Tory Bruno confirmed that ICPS production capacity continues to exist. This is notable as ULA has built their final, planned ICPS, which is intended for Artemis III.

The question: Will Artemis IV fly as planned, launching from ML2 and sporting the new EUS? Or will NASA fall back to Block 1 for this mission and choose to make further use of ULA’s production line?

Your predictions above, please.

DCSS5 production tooling will if needed move to MAF now that ICPS-3 and the last DCSS5 on the backlog have shipped. It is in the process of being mothballed for storage.

This was my understanding as well.  Either something has happened very recently (which would be big news) or he's using an extremely liberal interpretation of what "ICPS/DCSS production lines are still open" means.

[Coastal Ron]

Isn't the more important question is whether NASA will have an uncrewed test flight for the EUS BEFORE the Artemis IV mission?

Artemis I was uncrewed, and that used the ICPS, shouldn't the change of the 2nd stage merit an uncrewed test flight?

[TheRadicalModerate]

Isn't the more important question is whether NASA will have an uncrewed test flight for the EUS BEFORE the Artemis IV mission?

Artemis I was uncrewed, and that used the ICPS, shouldn't the change of the 2nd stage merit an uncrewed test flight?

Artemis I was more of an all-up test of the core than just the ICPS, IMO.

That said, the obvious answer to your perfectly reasonable question is that NASA can't afford an all-up test of Block 1B.

There's a lot that's new about EUS, but there's also a lot that's pretty well-trodden ground.  The RL10C-3 hasn't flown, but it's yet another variant of an extremely well-understood engine, with the usual variations in expansion ratio and O:F--not exactly [ahem] rocket science.  It has a new interstage, and of course you have the USA on the top instead of the LVSA.

The big change is that the tanks are composite, which is frankly insane.¹  I expect them to have all kinds of gnarly, cost-plus-supported problems with them.  But it's the kind of structural work that we know how to test on the ground.

____________
¹Does anybody know why NASA thought it was a good idea to go to composite over the aluminum isogrid?  Are the mass margins for Block 1B so tight that this is worth the exorbitant development costs?  Or is this a way for Boeing to fleece us just a little bit more?