From Ars Technica:

https://arstechnica.com/science/2021/12/rocket-report-sls-may-face-delay-due-to-engine-issue-astra-goes-orbital/

“ There’s an issue with an SLS engine controller. This past weekend, rumors emerged about a problem with the controller for one of the four RS-25 engines that power the Space Launch System. NASA has not officially commented, but Aviation Week’s Irene Klotz spoke with Aerojet’s RS-25 program manager Jeff Zotti. Troubleshooting on the problem began on November 22, Aviation Week reported.
Schedule impacts yet to be determined … If necessary, “replacing a line or a component … we’re probably talking about multiple days. Replacing an engine, we’re probably talking about multiple weeks,” Zotti told the publication. “On top of that, we have to assess what that does and how that affects the vehicle and the integration activities that are going on,” he added. All of that must be factored into a potential delay of the launch, presently scheduled for February 12. A summer launch for the SLS now seems far more likely than spring.”

I considered applying myself a few years back, but at the time this would have meant working at Hawthorne, and I just couldn’t stomach the thought of living in and driving through L.A. My current 100-mile roundtrip Phoenix commute is far preferable to that madness, and the living situation in L.A. has only grown horrifically worse since then too. Also, it looks like many of SpaceX’s employees skew younger – all the better to not burn out as fast!

I think it is very likely that Elon Musk will fail with his plans to colonize Mars. But can this man be satisfied with smaller plans?

That makes me think that either the management was not being “fully transparent” with Musk, so he was surprised when he checked in-depth, or that the same problem was holding things up time after time.

Despite having applied for a Space X job, I’m not sure I’d like to work there. Musk’s management style is, shall we say, intense.

https://www.youtube.com/watch?v=7kwAPr5G6WA

Nothing. During Huntsville’s glory years, the brains of the operation were a bunch of sheep dipped Germans led by an SS Major who was a war criminal. And past 1960, it didn’t design or build a single rocket – Atlas was designed and built by Convair, Titan by Martin, Saturn by Boeing, Noth American and Douglas. The godawful Shuttle by Rockwell. Marshall has been, at best, a subcontractor, with Houston and NASA HQ in Dc running the show

Elon Musk ? & Akira The Don
“If You Don’t Make Stuff, There Is No Stuff”
June 2020
https://youtu.be/nA4Ya-yKJ0A
3:23

Musk is a man who always walks on the line between madness and genius with his actions. This shows his apocalyptic style of communication. I said years ago that if Musk should fail, then only on a large scale and then primarily to himself or his own requirements.

If he does not achieve such a high level of operational reliability with this rocket engine that previously seemed unattainable for liquid rocket engines, the Starship project has failed, at least as a manned variant. This is that variant that is important for Musk. I am humble and would consider a unmanned space transport system that is fully reusable in all parts at low cost alreay as a huge success.

Apparently not much as they are trying* to use antique SSME and solids from the 70s.

*without visible success

Or you can have it 1)good enough 20 cheap enough and 3)quick enough

Comes from all that meth’ she does.

Glushko hated LH2, yet hydrogen engines run cool. The SSME equiv’ RD-0120 had no issues-where the hydrocarbon RD-170 gave him fits with burn throughs even with his old trick of multiple combustion chambers.

But what do Alabamians know about building rockets?

At some point, though…if your design is such that you can’t figure out an effective way to manufacture it in the needed quantity and time, the design *might* be a problem.

That aside, I am struck by the use of the word “reliable,” not least because rumors and comments by Elon over the last year keep pointing to reliability at the desired flight cadence as an issue they have been contending with.

Anyhow, Elon did add more tweets today. He insisted, in response to a query about the Raptor 2, that “It’s getting fixed.” Followed by:

“If a severe global recession were to dry up capital availability / liquidity while SpaceX was losing billions on Starlink & Starship, then bankruptcy, while still unlikely, is not impossible. GM & Chrysler went BK last recession. “Only the paranoid survive.” – Grove”

“The magnitude of the Starship program is not widely appreciated. It is designed to extend life to Mars (and the moon), which requires ~1000 times more payload to orbit than all current Earth rockets combined.”

Although a ferry system like this may seem to be a way to gain profitable use of Raptor/Starship earlier, it has the drawback of keeping SpaceX in the Falcon/Dragon business longer than it may want to be! I wonder if Falcon/Dragon will turn out to be the blockbuster product that is almost fatally successful for SpaceX?! In addition to multiple tanker missions for every Starship lunar mission, there will have to be (at least) one Falcon up-ferry and one down-ferry, and likely more. That’s a lotta rockets!!

https://www.youtube.com/watch?v=t705r8ICkRw&t=219s

Here are some quotes from a discussion about Raptor manufacturing:

“Manufacturing is underrated and design is overrated. …People generally think that there is this eureka moment… you come up with this idea and that’s it.”

“[with] a design like this, literally, a 1000%, maybe 10,000% more work goes into the production system than the thing itself… How much effort we put into designing Raptor versus designing the manufacturing system… it’s 10 to 100 times more effort to design the manufacturing system than the engine.

“The amount of effort that goes into the design rounds to zero compared to the amount of effort that goes into the manufacturing system.”