Artemis Moon Program

[NMaude]

The more Starships fly apart—the better SLS will look to anyone besides Musketeers.

Yup! Except that the Muskrat, like the Orange Oaf, has a Mt. Everest sized ego and that ego may demand that he try to screw with the SLS never mind that Starship is far from ready for commercial service.

I'd say that it's a sure bet that Artemis II will liftoff as it's already in the process of being stacked, Artemis III has had most of its' major components built and is almost ready for final assembly of its' first-stage (Its' ICPS, LVSA and SRB subassemblies are already in storage awaiting stacking). Artemis IV is in the early stages of subsystem assembly and Artemis V is IIRC having major structural parts for its' first-stage in the machining and bending stage.

 

[BlueAbyssal]

Given the abysmal performance of the SLS program, its guaranteed high cost, and low flight rate, name-calling and tribalism don’t engender support for the program at all. Unless you’re Boeing, there’s very little anyone can do to make the SLS better than it is, and they’re happy with how things are going. Money and jobs, not flying missions, is their top priority. Why wouldn’t it be? Congress wanted it that way from the start. SpaceX is attempting something dramatically more ambitious that no one has ever managed. Regardless of what the outcome is, if we actually care about having reliable transport to the Moon, starting to look for alternatives to the SLS right now is paramount. For people panicking about that sentence, that does not intrinsically mean getting rid of the SLS. It’s the same thinking behind having multiple cargo and manned transports for the ISS - if one has an issue, another can pick up the slack. Does going to the Moon actually matter? If so, two or more manned vehicles are required. If not, but sending money to Alabama and Louisiana is, then be open about it.

 

[NMaude]

I was checking over at the NASASpaceflight Heavy Lift Launcher forum and it had some news to do with the Artemis V first-stage thrust-section:

Quoted from the Artemis V thread:

https://images.nasa.gov/details/MAF_20241218_CS5_ESliftVWC03

Technicians at NASA’s Michoud Assembly Facility move the engine section of NASA’s Space Launch System rocket for Artemis V on December 18, 2024, at NASA Michoud Assembly Facility in New Orleans, LA. Throughout 2024, new tooling was erected in bldg. 115 for the upcoming iterations of the Space Launch System (SLS), Exploration Upper Stage (EUS), and the test articles required to develop and assemble each efficiently and effectively. This barrel is the sixty-fourth produced for the Space Launch System program since its inception and is the first barrel weld completed for the core stage of the Artemis V mission. This engine section will be used on the evolved Block 1B configuration of the SLS (Space Launch System) rocket. It is one of the first components that will make up a portion of the core stage that will power NASA’s Artemis V mission. According to a Boeing engineer, as of this barrel, the VWC has now completed 515 production welds, with friction-stir welding a cumulative distance of 111,568 inches. Image credit: NASA/Michael DeMocker

https://images.nasa.gov/details/MAF_20250210_CS5_LH2_Barrel_out_VWC-01

This image shows NASA’s Michoud Assembly Facility move crew lifting a completed liquid hydrogen tank barrel off the Vertical Weld Center on Feb. 10. The barrel, which will be used on the core stage of NASA’s SLS (Space Launch System) rocket, is one of the first pieces of flight hardware manufactured for the agency’s Artemis V mission. The 22-foot-tall barrel section is one of five barrels, which – along with two end domes – make up the 130.8-foot-tall liquid hydrogen fuel tank. The SLS core stage liquid hydrogen tank holds 537,000 gallons of super-cooled propellant and is one of five unique elements that make up the SLS core stage.

I keep forgetting just how big those barrel-sections for the LOX and LH2 tanks are.

Any it would appear that Boeing is already got production of major structural subsections for Artemis V's first-stage well under way.

 

[NMaude]

Apparently the Athena Moon-lander's laser-altimeter crapped out during the probe's descent, from the Space Bucket:

It's now been confirmed that the Athena lunar lander's altimeter failed around the time the spacecraft reached the Moon. This instrument is key in the process of determining the lander's distance from the surface, which it then uses during the final landing maneuver.

Without it, the Athena spacecraft didn't know its distance from the ground, which no doubt had an impact on the lander tipping over and sliding into its final resting place in a crater.

Credit:
Intuitive Machines - / @intuitivemachines

Chapters:
0:00 - Intro
0:29 - Altimeter Failure
4:36 - CEO Statement

 

[publiusr]

I keep forgetting just how big those barrel-sections for the LOX and LH2 tanks are.

They're getting better and probably could go faster--building something right to begin with let's you do that--where playing around is going to slow Starship development now--maybe Elon will find screaming at folks doesn't make them go faster.

That's okay--let the NewSpace tribalists think all we do is stay in rocking chairs over here.

Other views

SLS General Discussion Thread 8

SLS General Discussion Thread 8

forum.nasaspaceflight.com

SLS General Discussion Thread 8

SLS General Discussion Thread 8

forum.nasaspaceflight.com

 

[TomcatViP]

That's okay--let the NewSpace tribalists think all we do is stay in rocking chairs over here.

That...

 

[BlueAbyssal]

It’s absurd and childish, I agree. Eight full Starship prototypes have already been launched, compared to one test flight for the SLS, and Starship will certainly have more test launches before Artemis II than the SLS will launch total. Evidently Boeing isn’t doing things ‘right’ enough in order to build SLS cores at well under a tenth the rate SpaceX builds Starship stages every year.

 

[Kiltonge]

Apparently the Athena Moon-lander's laser-altimeter crapped out during the probe's descent, from the Space Bucket:

"Two is one and one is none" applies not only to back-ups but also diversity of sensors. Reliance on a single type is altimeter seems foolhardy; radalts are cheap and light

The more we learn about this lander the more I wonder how it regressed so far beyond 1960s design philosophy.

 

[Byeman]

They're getting better and probably could go faster--building something right to begin with let's you do that--where playing around is going to slow Starship development now--maybe Elon will find screaming at folks doesn't make them go faster.

That's okay--let the NewSpace tribalists think all we do is stay in rocking chairs over here.

not really. SLS is glacially slow. There isn't any real progress to see, since "improvements" haven't increase production rates above a snail's pace
Can't be stating that something will be "slowing" Starship development, when it has flown 7 times since the one SLS launch.
That is just changing the narrative to fit your perception of world (which is not shared with the majority).

That's okay--let the NewSpace tribalists think all we do is stay in rocking chairs over here.

Who is "we" and "here"?
"Stay in rocking chairs"? more like not even getting out of bed.

 

[Byeman]

The more Starships fly apart—the better SLS will look to anyone besides Musketeers.

That is far from happening.
In any universe, there is nothing that can make SLS look good. There isn't enough lipstick to make it look good. A pig is still a pig.
SLS is worse than LCS.
Artemis needs Starship. No Starship, no need for SLS.

 

[publiusr]

Now that you are retired--maybe get with SpaceX and give them a few pointers.

 

[Kiltonge]

Rough estimates are that each Starship test launch has cost around $100 million. Let's double that for the sake of argument. So, they could fly 20 complete failures before equalling one SLS launch bill...

And that's disregarding the $85 billion ( adjusted dollars ) already digested by SLS; another 400 Starship launches, or one-third of the entire Apollo program 1960-73.

The financial magnitude of SLS is breathtaking.

 

[Archibald]

The only useful role for SLS would be a variation of Zubrin's Mars Direct : dropping payloads to Mars surface to augment Starship missions.
But SLS can't even do that, because pathetic flight rate and $4 billion a single launch... also weak upper stage.

 

[BlueAbyssal]

Yes. It’s very difficult to shoehorn the SLS into any architecture which wants to be more ambitious than Apollo 8. In theory it can be done, but the resources needed to do so would achieve more if invested elsewhere.

 

[NMaude]

also weak upper stage.

I assume you're referring to the ICPS? Boeing already has the much higher capacity EUS in development.

 

[publiusr]

I want an NTR atop SLS.

Starship is fine for bulk payloads--I don't trust it beyond that.

 

[NMaude]

I want an NTR atop SLS.

Definitely handy if you want to send a crewed spacecraft to Mars and not want to spend eights getting there using conventional chemical propulsion, of course such a payload would have ALL of the greenie-luddites (Such as Greenpeace) coming out of the woodwork.

 

[BlueAbyssal]

Refueling at both ends cuts down on travel time substantially, and allows chemical propulsion to perform at a level otherwise unobtainable except through nuclear propulsion. There's no real need for nuclear for transit all the way out to the inner Main Belt. In any event, all of this is beyond the topic of Artemis, except for eventually refueling Starship on the Moon using lunar oxygen. There are already companies working on enabling just that.

 

[FighterJock]

I thought that it was the plan to use Starship to haul large capacity cargo to the Moon and let the astronauts go on the SLS publiusr, at least that was what I read somewhere online.

 

[BlueAbyssal]

Not quite. NASA presently intends to use Starship for manned landings with Artemis III and IV, where an Orion will meet a Starship in NRHO and transfer crew over. Starship is also contracted to deliver a rover to the surface for Astrolab, NET 2026. Other companies are also planning to use it in the future, but that is more speculative. For the nonce, the SLS’s payloads are limited to Orion capsules and a handful of Gateway modules.

 

[athpilot]

Trump White House drops diversity plan for Moon landing it created back in 2019

“We’re updating our language regarding plans to send crew to the lunar surface.”…

arstechnica.com

 

[TomcatViP]

To continue the discussion on Regolith, Moon Dust and Lunar Landers, here is a fun details on Blue Ghost recent touchdown:

View: https://youtu.be/7cPA9HCUeAc?si=0NrpBduW_SHHI3A_

 

[NMaude]

Not quite. NASA presently intends to use Starship for manned landings with Artemis III and IV, where an Orion will meet a Starship in NRHO and transfer crew over.

That's a big assumption by NASA that the Starship will be fully operational and human-rated by the time Artemis III lifts off from Cape Canaveral.

 

[BlueAbyssal]

It's an equal assumption that the EVA suits, Orion, and SLS will be ready by then. The White House and Congress were foolish for not articulating and funding a plan years sooner. During the Apollo years we didn't wait until Saturn V had successfully flown before developing the LM.

 

[Kiltonge]

That's a big assumption by NASA that the Starship will be fully operational and human-rated by the time Artemis III lifts off from Cape Canaveral.

Well Starship has its eighth test flight scheduled for April, so they're iterating through design changes on a monthly cadence.

Orion has flown twice since 2014 and still needs heatshield modifications. Might fly in April 2026.

 

[Byeman]

I want an NTR atop SLS.

Starship is fine for bulk payloads--I don't trust it beyond that.

Nonsense and inane. Trust has nothing to do with it. It will be based on a smart engineering decision when the time comes and not not on uninformed and biased internet forum posts. NTR isn’t flying tomorrow. By the time it is ready, SLS will have 5 or less times(or is cancelled). Starship will have flown maybe a 100 times and be proven.

 

[publiusr]

That's a big assumption by NASA that the Starship will be fully operational and human-rated by the time Artemis III lifts off from Cape Canaveral.

Agreed.

Had SLS come apart and Starship performed flawlessly, New Space would rub it in.

But the last two tests lost ground—the fail-often/fail-forward mantra is beginning to wear thin.

Where Falcon is indeed a fine example of test-to-destruction, Starship looks more and more to be an example of the Peter Principle…with Musk being a fine example of an individual who has risen to his level of incompetence.

Even critics of SLS concede the cost-plus bashing has gone too far:

SLS General Discussion Thread 8

SLS General Discussion Thread 8

forum.nasaspaceflight.com

 

[BlueAbyssal]

Falcon 1 failed three times in a row before SpaceX finally succeeded. Plenty of other entities have also had multiple losses in a row before they met their goals. Outside the company there simply isn’t the information to confidently say SpaceX has bit off more than they can chew. Plus they know it can get farther than it has, so it clearly isn’t an insurmountable problem.

Also, given that SpaceX is paying for Starship development out of company funds, it really doesn’t matter what anyone outside says. They want it for Mars, and they have the resources to keep going. NASA can cancel HLS contracts, but that wouldn’t change SpaceX’s internal purpose.

 

[publiusr]

Falcon had the blessing of coming apart after putting real payloads in orbit….like SLS…and Vulcan…and New Glenn—but unlike Starship.

Tory Bruno asks “where’s the Starship payload, Elon?”

Now if Elon wants SuperHeavy to be New Shepard on steroids…he’s ready…

Meanwhile, Arty II’s ride is stacked—it just takes time to PROPERLY test things:

Artemis II : Updates and Discussion Thread : NET April 2026

Artemis II : Updates and Discussion Thread : NET April 2026

forum.nasaspaceflight.com

 

[BlueAbyssal]

SpaceX did not have the luxury of waiting to put payloads aboard Falcon 1. They do with Starship. If all they wanted to do was build an expendable upper stage, they could have been launching operationally long ago, as all those vehicles have, but they’re trying for something more. Complaining they haven’t put a payload into orbit yet is like complaining someone just starting a 5K hasn’t finished the race a few minutes after getting onto the track.

 

[NMaude]

Phillip Sloss has an Artemis II status update:

The flight hardware for Artemis II was passing a couple more milestones as the week ended. The Orion service module is encapsulated and the Exploration Ground Systems had started stacking operations to mate the SLS Core Stage to the Boosters in the Vehicle Assembly Building at the Kennedy Space Center. This video goes over those milestones and what's next, including an RS-25 engine changeout.

I also got an update on the Artemis II training schedule, and there are news and notes on politics and Artemis IV hardware welding

.Imagery is courtesy of NASA, except where noted.

Links to social media posts:
https://www.youtube.com/redirect?event=video_description&redir_token=QUFFLUhqa2xIS2hjZy1LR1QtT2RvdTQ4VXhMMXp5YmdRd3xBQ3Jtc0ttVDRZbmZfVFpNd08tX3RCd1lpX19jU0wydzlpenlQcnp1aEhNMlFpQW5BS2RUVDRKbUxDM215dmJuRXlHZWdVNWo0a3JBYmliSi1FYk92WUp3QW5WMS1iU0E3REFaZDl1RDJWWHhtX0VOdGxzV01EWQ&q=https://www.facebook.com/NASAGroundSystems/posts/pfbid02WLG3DCRF9Cq9xPL7qHY8LL1JVPFmPCwgf4owsAjS8XgAAKyyayHz48m83WTDGNpol&v=rnOTye3j8vA
/ pfbid02wlg3dcrf9cq9xpl7qhy8ll1jvpfmpcwgf4o... https://www.youtube.com/redirect?event=video_description&redir_token=QUFFLUhqa2xIS2hjZy1LR1QtT2RvdTQ4VXhMMXp5YmdRd3xBQ3Jtc0ttVDRZbmZfVFpNd08tX3RCd1lpX19jU0wydzlpenlQcnp1aEhNMlFpQW5BS2RUVDRKbUxDM215dmJuRXlHZWdVNWo0a3JBYmliSi1FYk92WUp3QW5WMS1iU0E3REFaZDl1RDJWWHhtX0VOdGxzV01EWQ&q=https://www.facebook.com/NASAGroundSystems/posts/pfbid02WLG3DCRF9Cq9xPL7qHY8LL1JVPFmPCwgf4owsAjS8XgAAKyyayHz48m83WTDGNpol&v=rnOTye3j8vA
https://bsky.app/profile/astro-g-dogg...https://www.youtube.com/redirect?event=video_description&redir_token=QUFFLUhqa19XdTVUMklHd1hZY3JNT3ZpM0NiZWpuaFc1QXxBQ3Jtc0trMHhtNlU1ZjVvS0EtZk1UU3RyQzAwZXhObi1DY2tzZXlqUDBTSnVOWFh4TE94dTA4Z3k0cHVSa3V1cXQxdW5pdFNHYktESnkwV1A0SDkteXRkQXpIU1dycWdUSkt2eUxEVHRQUEVoNXIzZHJfdUcyYw&q=https://bsky.app/profile/astro-g-dogg.bsky.social/post/3lkwd6hw5dk2l&v=rnOTye3j8vA

Links to stories referenced:
https://www.nasa.gov/image-article/na...
https://www.youtube.com/redirect?event=video_description&redir_token=QUFFLUhqa3QzaWs5bzVIUWdVT1NnRFBnN2F4QkhnSHc0d3xBQ3Jtc0tuYm02cVk0aTI1Z25Xc1gyNnlSTzVReVhKUlZDY0t1ZmlpVzRwQUt5YmxZRkpKeUlmSEZCeWtjLXludWZuYUxEc05XQWlHZTlSRi1kQlctb1pXc1dQSHJiQ3VSenh3Q01LQ21nbk5vRURhWkVBeEptdw&q=https://www.nasa.gov/image-article/nasas-artemis-ii-orion-service-module-buttoned-up-for-launch/&v=rnOTye3j8vA
https://www.youtube.com/watch?v=rnOTye3j8vA

00:00 Intro
00:49 Artemis II Orion and SLS milestones this week
01:16 Orion Service Module encapsulated for launch
02:51 SLS Core Stage lift begins for stacking with Boosters
06:29 LVSA moved back where it was before
07:35 Core Stage engine 4, RS-25 engine 2063 will be replaced with engine 2061
12:08 Artemis II training update from mission manager Matt Ramsey
16:46 Other news and notes, beginning with Artemis IV
18:05 Former NASA astronauts support Jared Isaacman's NASA Administrator nomination
19:42 Thanks for watching!

 

[NMaude]

Philip Sloss has a new Artemis II update video out:

About this time a week ago, NASA Exploration Ground Systems was lining up the Artemis II SLS Core Stage to be bolted with its Solid Rocket Boosters for the first crewed Artemis lunar mission. The official launch date for the lunar flyby mission is still a year away, but the goal is to launch sooner than that.

There's still a lot of work to get the Orion and SLS hardware ready to fly, and in this video after I go through the Core Stage lift-to-mate operations last weekend I'll try to put into perspective some of the work that remains.

In parallel with the vehicle preparations, the astronauts and ground support teams are also practicing for what happens not just during the mission, but before and after, and NASA posted some imagery of an ongoing landing and recovery exercise off the coast of San Diego. I'll go a few of those, a couple of updates on the initial Gateway modules, and possible dates for the political calendar.

Imagery is courtesy of NASA, except where noted.

00:00 Intro
01:10 SLS Core Stage lift to mate joins them with Artemis II SLS Boosters
07:03 Artemis II astronaut Reid Wiseman's weekly update provides a status update on VAB work
08:46 A lot of work to do before stacking the next SLS element
11:01 Orion Stage Adapter shipping update
12:08 A quick look at the Artemis II big picture now that the Core Stage and Boosters are mated
12:59 EGS landing and recovery practice underway off the San Diego coast
15:27 Other news and notes, beginning with the Gateway PPE and HALO modules
16:44 A couple of political notes about what's on the upcoming calendar, likely in May or after
17:36 Thanks for watching and thanks to channel members for their support!

https://www.youtube.com/redirect?ev...ance-of-power-to-the-president/&v=hEHfeyrZIK4

 

[TheKutKu]

https://www.wsj.com/business/elon-musk-nasa-mars-space-travel-d3978a7b

WSJ reports on possible Artemis changes...

Some excerpts:

The White House plans to propose killing a powerful Boeing-built rocket designed for NASA to launch astronauts to the moon and beyond in a coming budget plan, according to people briefed on the plans. Canceling the vehicle, called the Space Launch System or SLS, would potentially free up billions for Mars efforts and set up a clash with members of Congress who support it.

SpaceX officials have told people outside the company in recent weeks that NASA’s resources will be reallocated toward Mars efforts.

SpaceX President Gwynne Shotwell has told industry and government peers that her work is increasingly focused on getting to Mars. Inside SpaceX, employees have been told to prioritize Mars-related work on its deep-space rocket over NASA’s moon program when those efforts conflict.

And NASA’s program known as Artemis, its long-range plan to explore the moon and eventually Mars, is being rethought to make Mars a priority. One idea: Musk and government officials have discussed a scenario in which SpaceX would give up its moon-focused Artemis contracts worth more than $4 billion to free up funds for Mars-related projects, a person briefed on the discussions said.

Officials from Trump’s Office of Management and Budget have told people about discussions under way to move U.S. government dollars toward Mars initiatives and away from programs focused on the moon and science missions. Killing or dramatically remaking the program would unravel years of development work, but some proponents say much of the hardware for Artemis, from the SLS rocket to ground infrastructure, is too expensive, slow to produce and behind schedule.

I don't think the fact that all of this is being discussed will come at a surprise of anyone who's been aware of NASA politics and Musk and SX's goals over the past years. The question is how much pushback will there be against this.

I'd note that SpaceX has received ~2/3 of the awarded HLS contract funding, despite being ~1 year away from the next big step that is the propellant transfer demo, which is necessary for the Critical Design review of SpaceX HLS. This is due to how the milestone were set (mostly by NASA, a bit by SpaceX)

 

[NMaude]

The question is how much pushback will there be against this.

There will be a LOT of pushback all due to pork-barrel politics, this further shows why Musk must be kicked out of the Trump administration ASAP.

 

[BlueAbyssal]

I don't think the fact that all of this is being discussed will come at a surprise of anyone who's been aware of NASA politics and Musk and SX's goals over the past years. The question is how much pushback will there be against this.

I'd note that SpaceX has received ~2/3 of the awarded HLS contract funding, despite being ~1 year away from the next big step that is the propellant transfer demo, which is necessary for the Critical Design review of SpaceX HLS. This is due to how the milestone were set (mostly by NASA, a bit by SpaceX)

There's also the question of how much of it is true. What people were briefed? Which SpaceX officials? Who outside the company? Given the furor around Musk, I'm far more skeptical of reports (both good and bad, incidentally) surrounding him and SpaceX these days. There's no secret that SpaceX is primarily interested in Mars and has been since the company was founded.

There will be a LOT of pushback all due to pork-barrel politics, this further shows why Musk must be kicked out of the Trump administration ASAP.

Depends on how those dollars are redirected. The handful of members of Congress who have the most to lose from the SLS or Orion being canceled may be much less strident if the White House is smarter than Obama was, and offers a plan that can still make use of the workforces Congress cares about. They are not, in the main, that attached to the Moon as a destination, or the SLS and Orion as vehicles, other than as a means to different ends.

 

[TheKutKu]

There's no secret that SpaceX is primarily interested in Mars and has been since the company was founded.

Indeed, and Musk has a one in a lifetime opportunity to attempt to redirect NASA's crewed spaceflight effort to Mars. He sees urgency in going to mars.
None of this would surprise me. Someone who wants to deorbit the ISS (with its lucrative Dragon contracts) in 2 years to focus on Mars would likely have no problem to cut through Artemis' lunar part and redirect that funding and particularly manpower (arguably more important than funding) to mars.

I don't see the US abandonning crewed lunar exploration, especially with China's landing and lunar base plans, but I can definitely see it having a lower priority than going to mars.

After all Artemis is, ultimately, a Mars program, this was the goal from day one.

 

[BlueAbyssal]

Whatever SpaceX and NASA do, Bezos (and thus Blue Origin) is highly interested in the Moon, and they're not the only ones. They may not have the resources to move as quickly as they could if NASA downscopes its lunar ambitions, but that only matters until someone can make a profit.

 

[southwestforests]

Artemis moon program provides a reenlistment experience to remember;
Just saw these via one of NASA's several albums on Flickr photo hosting website,

NASA Artemis Undreway Recovery Test 12 (NHQ202503290023)

NASA astronaut U.S. Navy Capt. Victor Glover provides the oath of re-enlistment to Aircrew Survival Equipmentman 2nd Class Noah Boggs in the Crew Module Test Article (CMTA) during Underway Recovery Test-12 onboard USS Somerset off the coast of California, Saturday, March 29, 2025.

NASA Artemis Undreway Recovery Test 12 (NHQ202503290023) by NASA HQ PHOTO, on Flickr

NASA Artemis Undreway Recovery Test 12 (NHQ202503290024)

NASA astronaut U.S. Navy Capt. Victor Glover provides the oath of re-enlistment to Aviation Ordnanceman Senior Chief Petty Officer Scott Keating in the Crew Module Test Article (CMTA) during Underway Recovery Test-12 onboard USS Somerset off the coast of California, Saturday, March 29, 2025.

NASA Artemis Undreway Recovery Test 12 (NHQ202503290024) by NASA HQ PHOTO, on Flickr

 

[Kiltonge]

Agreed.

Had SLS come apart and Starship performed flawlessly, New Space would rub it in.

But the last two tests lost ground—the fail-often/fail-forward mantra is beginning to wear thin.

Wear thin?

Much as I'd rather not admit it, SpaceX are so far ahead of the rest of commercial spaceflight that they could probably 'fail fast' for the next decade and still come out ahead.

In comparison, Artemis isn't even shifting the needle compared to 1960s spaceflight principles. Just the same pattern, even regressing somewhat - and struggling.

There is literally no basis for comparison. I don't know on what grounds Artemis / SLS can be defended in any aspect.

 

[BlueAbyssal]

There is literally no basis for comparison. I don't know on what grounds Artemis / SLS can be defended in any aspect.

The usual defenses I've heard run the gamut of: SLS worked (aka flew a nominal mission); it costs what it costs, and we can't reasonably expect lower costs; it employs lots of people and thus is valuable from that perspective alone; there's no viable commercial rationale for manned spaceflight, so if we want to see it at all it has to be government-run; there is nothing comparable available any time soon (which is usually defined as 'capable of sending Orion to NRHO in a single launch'); and then various sophistries and self-serving justifications that aren't worth repeating. I am not unsympathetic, but I find most defenders unwilling to examine detractors' arguments in good faith. It makes for tedious discussions that usually don't go anywhere.