Is NASA’s SLS Doomed?

[tdracer]

A former supporter of SLS is withdrawing his support:

Long-time advocate of SLS rocket says it’s time to find an “off-ramp” - Ars Technica

On Wednesday, one of the Republican space policy leaders most consistently opposed to commercial heavy lift rockets over the last decade—as an alternative to NASA's large SLS rocket—has changed his mind.

"We need an off-ramp for reliance on the SLS," said Scott Pace, director of the Space Policy Institute at George Washington University, in written testimony. He issued the statement in advance of a hearing about US space policy, and the future of NASA's Artemis Moon program, before a subcommittee of the House Committee on Science, Space, and Technology.

As part of his policy recommendations, Pace said NASA should seek to use commercial providers of heavy lift launch so that NASA can send "multiple" crew and cargo missions to the Moon each year. He notes that the SLS rocket is not reusable and is incapable of a high flight rate. "It has had one flight, but has trouble supporting one flight per year, much less congressional targets of two 'cores' per year," Pace said.

[tdracer]

More SLS issues:

New SLS booster design suffers anomaly during test - SpaceNews

A new version of the solid rocket booster being developed for the Space Launch System experienced an anomaly during a test firing in Utah June 26.

A little more than 100 seconds into the test, exhaust appeared from come out from the side of the nozzle. Seconds later, debris scattered from the vicinity of the nozzle, as seen in NASA’s webcast of the test.

While this is a significant change to the solid boosters (carbon composite casing vs. the existing steel construction), this is still a pretty big 'whoops' for something that was supposed to be based on 'mature' technologies.

[ORAC]

Hope he took a deep breath after getting this off his chest..... (Warning - it's not brief)

https://caseyhandmer.wordpress.com/2...aming-garbage/

NASA’s Orion Space Capsule Is Flaming Garbage

For many years, readers have asked me a simple question:

“Casey, why do you hate the SLS so much? Don’t you also hate Orion?”

Yes, yes I do. But life is finite and my heart is mostly filled with love, and so I held off in the hope that either someone else would step forth and deliver a blistering tirade, or perhaps Orion would finally succumb to the magnitude of its contradictions and die a mostly peaceful death, unlike the astronauts who are fated to roll the dice in this thing this year. I mean next year. Well, at any rate probably before they die of natural causes in old age.

Here is a brief summary of previous posts on the SLS+Orion program. Prior to this point I’ve reserved most of my critique for SLS. And for new readers of this blog, you’ll find that 98% of my writing is technical, positive, and I hope interesting. But someone has to write a pointed critique every now and then.........

[51bravo]

Good Lord,

I sincerely hope Reid Wiseman, Victor Glover, Christina Koch, and Jeremy Hanson, have read this. Or at least their wifes, husband resp. !

[51bravo]

And here they go, in approximately two weeks, Artemis II.

https://x.com/SciGuySpace/status/2014048229298471145

By the way the crew congratulated Buzz Aldrin to his 96th birthday back a few days. I wonder how he is doing, those days. He should be invited to Houston, I hope?
Or maybe all four of the still living Moonwalkers?
https://www.bluewin.ch/en/news/moon-...y-3055562.html

...Before the start of the first manned moon mission by the US space agency Nasa in more than half a century, the "Artemis 2" crew wished the second man on the moon a happy 96th birthday on Tuesday. "Happy Birthday Buzz," said Nasa astronaut Reid Wiseman (50) at a press conference - on behalf of the entire "Artemis 2" crew, which also includes Nasa astronauts Christina Koch and Victor Glover as well as Canadian astronaut Jeremy Hansen. ...

[ORAC]

NASA:

Due to weather, we now plan to fuel our Artemis II Moon rocket on Monday, Feb. 2, at Kennedy Space Center in Florida. With this adjustment, the earliest possible launch date is Sunday, Feb. 8. A launch date will be set after teams have reviewed the results of the wet dress rehearsal. Read more: https://t.co/eNxx6YcGbv
​​​​​​​

[B Fraser]

I was going for Feb 6th as this is when the back side of the moon is fully lit. No human has set eyes on this part as the Apollo missions were flown when the nearside was approaching full moon.

The 8th though should still be rather spectacular. NASA have my number should any of the crew fall ill. I'll even pay my own air fare to Florida and take my own food.

[ORAC]

Launch delayed till at least March, Artemis’s. Rolled back to the assembly building to investigate/repair a chronic hydrogen seal leak encountered during the dress rehearsal full fuelling.

[wiggy]

Originally Posted by B Fraser

I was going for Feb 6th as this is when the back side of the moon is fully lit. No human has set eyes on this part as the Apollo missions were flown when the nearside was approaching full moon.

.

Not quite...

Due to visibility requirements (low sun angle with sun behind the lander) those Apollo missions targeted to the more easterly landing sites, that’s 11 and 17, landed when the Moon was a crescent, not even at First quarter, so those crews got a decent look at a strip of the far side, as indeed did the crews of the two rehearsal flights for 11- Apollos 8 and 10, since they flew with the same lighting conditions.

It’s true through that there’s is a big chunk of the far side that man has never directly observed, and what the Artemis crew will get, because of the fly past distance is much greater than Apollo’s orbital height, is a better view of the far side hemisphere than any of those crews got.

[51bravo]

Here is how it should look like:
https://svs.gsfc.nasa.gov/5536/

time compression factor 1min ~= 36 hours (first video, the second one below is better)

[WillowRun 6-3]

Originally Posted by ORAC

Launch delayed till at least March, Artemis’s. Rolled back to the assembly building to investigate/repair a chronic hydrogen seal leak encountered during the dress rehearsal full fuelling.

Widely reported to still be on the launch pad, not returned to the VAB. Some reporting also suggests that crawler-transporter traverse may introduce stresses which are difficult to model accurately (unlike the essentially stationary environment of the pad) and which could be at the root of the pesky hydrogen seal leak.

[cavuman1]

I have the horrible premonition of an Apollo 1-like catastrophe developing. Artemis Safe to Fly? I sincerely hope I am mistaken.

We of a certain age remember Virgil "Gus" Grissom's concern over communications glitches in the capsule which had been built by a consortium comprising North American Aviation, Boeing, McDonnell-Douglas, and Grumman. He called it a lemon! Did too many cooks spoil the broth and kill 3 of America's top astronauts?

Boeing's design and build-out of the Artemis capsule has run millions over budget and years late. Artemis 1 showed very concerning damage to its heat shield. Artemis II, if and when they get her off the ground, will follow a more shallow re-entry path to limit heating. Fingers crossed!

- Ed

[51bravo]

Well at least, again, we have qualified experts (dependent) from the inside, who say: it is safe enough all-in-all. And we have qualified experts from the outside (more free in what thay can say publicly), with experience on the matter, but no deep access to the data - who say: too high of a risk, even for test pilots job holders. Was it not always like this?

For us here, well - each one is up to his own expertise and gut feelings. I am missing for my part some specifics of the slightly changed staged reentry sequence. If you make it "more shallow", according to my maths it means less delta-v loss the first dip into atmosphere, but more delta-v (energy) left for the second one. So what exactly are they planning for the second&final re-entry to reduce the max heat load and/or very high heat exposure duration?

[B Fraser]

Originally Posted by cavuman1

I have the horrible premonition of an Apollo 1-like catastrophe developing. .......We of a certain age remember Virgil "Gus" Grissom's concern over communications glitches in the capsule which had been built by a consortium comprising North American Aviation, Boeing, McDonnell-Douglas, and Grumman. He called it a lemon! Did too many cooks spoil the broth and kill 3 of America's top astronauts?

The flaw was pressurising the capsule with 100% O2 at ambient pressure. IIRC, the capsule would have a pure O2 atmosphere in flight however the pressure would be low to allow lightweight construction while delivering an acceptable partial pressure of O2 equal to that found at sea level. The ISS has a normal 14.7 psi mix of oxygen and nitrogen. I'm not sure about Artemis but would expect it to be the same.

[wiggy]

1. Ref the hydrogen problem (leak in the Tail mast quick disconnect area), TBF that’s not a problem confined to SLS, pumping LH2 is fraught with difficulty and it’s a problem of a type that has popped up regularly ever since hydrogen was used as a fuel… even on Apollo 11 a crew had out to the pad shortly before launch to torque up a few bolts to stop a leak in a pipe used to top H2 up in one of the tanks.

2. Atmosphere in Orion cabin : Hard to find a definitive answer but as I recall it with Orion it’s variable.

AFAIK the idea is to launch with the cabin ventilated with air at 1 bar but certainly on missions where there is going to be an EVA (see edit) it would then gradually to morph to (?) About 2/3 of a bar but oxygen rich (30% 02).

The thinking behind that is that is to reduce the time spent pre breathing with 02 prior to EVAs, where you need to be at low pressure but high 02 to keep the suits flexible.

Pre- breathing pure O2 to get the N2 out of the body is needed to avoid decompression sickness and ISS experience has shown the pre-breathing times if you start from being in air at 1 bar can really really extend EVA prep time…

(The above of course is one of several reasons why early US spacecraft went with 100% 02 low pressure in flight, the foul up was using 100% in the cabin on the pad at 1 bar)

ETA: I missed a step…The EVAs of course will not be ex-Orion, they will be ex HLS on the Lunar surface…the thinking AFAIK and ATM is that HLS or the gateway (if ever built) will be low’ish pressure, O2 rich, cabins for the reason previously stated, so Orion will have to match that for docking.

[WillowRun 6-3]

Originally Posted by cavuman1

I have the horrible premonition of an Apollo 1-like catastrophe developing. Artemis Safe to Fly? I sincerely hope I am mistaken.

We of a certain age remember Virgil "Gus" Grissom's concern over communications glitches in the capsule which had been built by a consortium comprising North American Aviation, Boeing, McDonnell-Douglas, and Grumman. He called it a lemon! Did too many cooks spoil the broth and kill 3 of America's top astronauts?

Boeing's design and build-out of the Artemis capsule has run millions over budget and years late. Artemis 1 showed very concerning damage to its heat shield. Artemis II, if and when they get her off the ground, will follow a more shallow re-entry path to limit heating. Fingers crossed!

- Ed

Isn't Northrup Grumman, not Boeing, the contractor for the Orion spacecraft in the U.S. NASA Artemis program?

Not to presume your answer, but if you're referring to Boeing's difficulties with its Starliner Commercial Crew spacecraft . . . . the ISS is quite a different destination and mission compared to the lunar program, and not directly relevant.

[cavuman1]

Yes, WillowRun 6-3, I am thinking of both the Starliner and the Orion spacecraft. Neither have lengthy proven histories and both have had demonstrable glitches. They do not approach Mr. Musk's Falcon/Dragon combination for flight frequency, safety, and reuseability. I understand your differentiation of destination, be it LEO, ISS, Moon, or Mars. All require a lot of thrust to get there, parachutes to return, and amazing engineering the whole way. I am concerned that the admixture of "Big Gummint" and Corporate Bureaucracy may be an equation which compromises safety. One need not look further than Challenger and Columbia to see my point, which I believe to be entirely relevant.

- Ed

[WillowRun 6-3]

Originally Posted by cavuman1

Yes, WillowRun 6-3, I am thinking of both the Starliner and the Orion spacecraft. Neither have lengthy proven histories and both have had demonstrable glitches. They do not approach Mr. Musk's Falcon/Dragon combination for flight frequency, safety, and reuseability. I understand your differentiation of destination, be it LEO, ISS, Moon, or Mars. All require a lot of thrust to get there, parachutes to return, and amazing engineering the whole way. I am concerned that the admixture of "Big Gummint" and Corporate Bureaucracy may be an equation which compromises safety. One need not look further than Challenger and Columbia to see my point, which I believe to be entirely relevant.

- Ed

As a relatively minor point regarding Orion, Northrop Grumman as a prime contractor has not been tarred and feathered the way Boeing has been dinged (MAX, door plug unplugging). Even though Boeing had legacy credibility from Apollo, it lost its way - but the Grumman heritage at NG . . . LM, TELMU and all that. I have more faith . . . but then I can tell you exactly where I was when the news came over the radio about the Apollo 1 pad fire (I was 14 at the time) so, no claim to complete objectivity.

As to the technical matters with regard to the Orion heat shield, I did not save the citation to the article but only a few weeks ago I read an article which reported on the extensive discussions offered by two participants in the safety review, one an internal expert and the other essentially an outsider. At the risk of omitting something important from the article, the two participants discussed that the material of the heat shield had experienced outgassing, and the extent or duration (or both) of this process had not been completely anticipated by NASA or the manufacturer. Also iirc, the plan for Artemis II is to fly (as noted by others) a different re-entry trajectory rather than redesign the heat shield - although (again iirc) this is being done for Artemis III.

Somewhat relatedly to all the above about Orion, it is fine to point out that it has no established track record, and then point to Dragon which does. But Dragon was able to build upon the successes of the human spaceflight program in a way that does not apply to deep space missions (isn't the velocity at which the lunar missions return to Earth much higher than deorbit from LEO? - and isn't the Orion spacecraft a much heavier spacecraft? - and a more complex one, given its deep space mission requirements?) ((And I don't have much to say about Starliner, other than NASA made the right decision not to risk bringing Butch and Sunni home in it.))

There is one other point about SpaceX flight hardware and its overall program that I believe is important to at least try to articulate. On one hand, starting with the troubled legacy of Dr. Von Braun through which the United States embarked on the technology and engineering initiative which culminated not only in the successful Apollo lunar landings but also in U.S. preeminence in space programs and technology, the United States space efforts have always been an expression of national will and purpose, decided upon and endorsed by the body politic. (That is, even though to imagine the Congress and successive White House administrations as "bodies", politic or otherwise, is more than slightly gross.)
On the other hand, SpaceX carries the decisions and endorsement almost exclusively of only one individual person. No question, no dispute, that SpaceX's conquering of reusability of space launch vehicles is a testament to several things - to the free enterprise system, to the ingenuity and "it" factor of the individual whose vision became the reality, and to some extent, even to a modest flexibility of the NASA bureaucracy. But carrying the flag, being appointed as "the United States" in the space hardware domain, should require something more than success in efforts so far. And I'll give a timely and concrete example.

The design of the HLS (Starship as a lunar landing spacecraft) requires orbital fuel depots and several transfers of cryogenic propellant. In the Apollo program (and Mercury and Gemini before) the engineering and technology risks were carried by the institutions and program elements across the country, in industry, government (not only NASA), academia. The story of how the LRV was designed and how that design was made to fit into the LM is a good example but far from the only one. Today, the big hurdle is cryogenic propellant management on orbit, in the depots and the transfers. Is this something that the United States national interest in space programs and technology should allow to be essentially contracted out? And in considering an answer, it might be useful also to consider, "Cryogenic propellant management in space: open challenges and perspectives", A. Simonini (et al.) npj microgravity (2024 10:34). (As a caveat to the foregoing, of course NASA is quite involved in the cryogenic propellant work being conducted by SpaceX. The difference is that if the legacy space model did not deliver the correct engineering and technology, by definition the voting public could exact political accountability. Though there could be something like accountability if and when the single most important engineering and technology risk is not addressed successfully by a private sector hardware provider, it would be significantly less than in the legacy model, if it even would be accountability at all.)

Edit; how the LRV was designed and made to fit into LM.

[cavuman1]

A very well-reasoned and objective response, WillowRun 6-3. I am in agreement. Surely within your attorney's breast there beats the heart of a human!

Highest Regards,

Ed

[WillowRun 6-3]

Originally Posted by cavuman1

A very well-reasoned and objective response, WillowRun 6-3. I am in agreement. Surely within your attorney's breast there beats the heart of a human!

Highest Regards,

Ed

Thanks very much!