Is NASA’s Space Launch System doomed because of obsolete components?


The Silicon Graybeard argues that they’re a major factor in the problems the SLS is currently experiencing – particularly in the prototype’s fuel system.

The persistent issues that have been arising with trying to fuel Artemis I for its maiden flight are drawing attention to an awkward conclusion.  Either the contractors for Artemis and whoever is running Mission Control forgot how to work with liquid hydrogen or everyone who knew how to do it has retired or otherwise left the business.  There’s a simple root cause, though, embedded in the joke that the SLS is “the Shuttles’ Leftover S***.”  The Shuttle program had trouble with liquid H2 as well and since the SLS program is reusing the Space Shuttle Main Engines, they have to use Hydrogen and Oxygen just like the Shuttles did.

. . .

If hydrogen is so hard to work with and hard to handle compared to kerosene (RP-1) or methane, why use it?  Back to the first paragraph: when congress allocated funds to start the program they mandated the use of the Shuttle hardware.  At this point, it might add some perspective to consider much of the Shuttle hardware was designed around 45 years ago.

. . .

Last Saturday’s countdown – cancelled when the hydrogen tank was 11% filled – was the sixth time they’ve attempted to fuel this launch vehicle; it’s tempting to call these tests a WDR (wet dress rehearsal) but I don’t think they really accomplished enough to deserve that name.

How much do you want to bet that the seventh time will be the charm?

There’s more at the link.  It makes very interesting reading, particularly for aviation and spaceflight buffs.

I wasn’t aware that the SLS program was mandated to use old, surplus Space Shuttle hardware.  That makes no sense to me at all.  If those components were designed back in the 1970’s, when the Space Shuttle was conceived, why would we not replace them with more modern hardware designed in the 2000’s, with all the improvements we’ve been able to come up with during the intervening decades?

I guess we can blame the politicians.  They wanted to look good to their constituents by “saving money”, so they voted to reuse old, obsolete technology.  (For that matter, NASA may have included Shuttle technology in their proposal precisely because they knew that “saving money” would be popular with those who vote to fund the agency.)

I suppose it’s like the old joke tells us:  “A camel is a horse, designed by a committee.”  (Comprised of politicians and bureaucrats!)



  1. Peter, it’s much worse than that …

    SLS has always been a pork project for Congress. There really has not been any incentive to actually produce a working spacecraft, NASA is bound by their funding.

    Read some of the posts at Rand Simberg’s blog Transterrestrial Musings Like this one …
    Hangar Queen

  2. "Hey, Charlie, we've got some old O-ring gaskets left over from the Shuttle SRBs. Should we put 'em in spare parts bin, or what?"

  3. Oh, that's quite an interesting prospect you got there. It would be hilarious if it wasn't so eye wateringly expensive.

    Worst case scenario, it's either tragic fireworks or a very big and expensive monument to the work of committees.


  4. All of this is complicated by the fact that NASA has been turned into a diversity entitlement program and when that happens to any organization everybody who actually knows what they are doing takes a hike.

  5. Oh, that's easy to answer. According to the Holy Book of Global Warming (which is the only orthodoxy allowed now), kerosene is evil because it's a petroleum product and will kill us all; methane is caused by evil cows and will kill us all. Hydrogen and Oxygen are Good, because they make water.
    Clear now?

  6. Just going to put it out there….we don't need the space program. Let's accomplish real problems here on earth before we wander around the stars.

  7. 1) All the greybeards are gone once the Shuttle program was killed, the youngsters run the troop now. Hard learned lessons are forgotten, even when documented. And it's true, being politically correct is more important that being scientifically correct.

    2) NASA could not even simulate a complete countdown for testing before the launch. I find that mind boggling.

    3) There is never any incentive for the contractors to meet deadlines or mileposts. In fact, more billable hours, more change orders, the better for the contractors. To paraphrase a remark I heard on one job," We'll get this job finished if it takes every penny NASA has!"

    Before I retired, our company worked on an issue on the ISS. I would love to go to space but Ill pass on that rocket system.

  8. Once again Congress has tried to use old hardware (shuttle leftovers) to "Save Money". They've been doing this forever, on classic version of this was Liberty engines at the end of WWI. They'd bought hordes of them and then the Jenny's that used them really weren't up to the task of matching hardware that was available. So they made the Army Air Force use them up and probably held back US military aviation until almost WWII. The SSME engines really were a bizarre compromise even for the shuttle. Originally the shuttle was to be carried aloft by a giant aircraft that would take off and land from a regular (albeit LONG) runway. At somewhere in the 50-60 thousand foot range the Shuttle would be kicked loose and go to orbit on its Hydrogen/LOX engines which at altitude weren't half bad. But then the launcher was too expensive (and technically probably at or just past the limits of what could be built mid 70's) so things got redirected and we launched from the ground ultimately ending up with the solid fuel boosters (also a compromise driven by cost and complexity). The SLS has taken the solid fuel boosters (with their notorious issues) and gone to 5 segments instead of 4. It has also used the SSME engines which were blindingly expensive and notoriously cranky and leak prone and it is just going to throw them away (at least the shuttle reused them although the often ended up refurbed/swapped between flights). At this point SLS is just a gravy train for Pols from many states. I give 60% chance it never flies, 30% chance it flies only once, 10% chance first flight fails catastrophically or is destroyed by range safety and program is canceled. Any one with a brain would go support Musk and Starship but these are congress critters so nary a brain cell between them.

  9. NASA was screwed when Charlie Bolden was appointed head of NASA. It was a permanent screw up as were just about all of Obama's picks for heads of agencies. I met him at the MENA conference in Doha. I am summoned to dinner. I will take this up later.

  10. An interesting tidbit in this mess is that the launch tower cost $1B to refurbish, and it can only be used for the first three SLS launches (missions 4+ require a different configuration that this tower can't support), the new tower is years behind schedule and somewhere north of triple it's 'budget' and expected to be delayed more and cost more.

    So I think there's a good chance that it will fly 2-3 times (I'm not saying successfully, just fly), but then the several year delay before the next launch will give SpaceX plenty of time to show that the Starship is a better rocket (even if it were used in expendable mode)

    Fun trivial item, the Starship booster is so powerful that you could put an entire SLS on top of it and launch it.

  11. SLS= Senate Launch System

    Re-using the Shuttle main engines kept ALOT of $$$$ + work in Huntsville, AL over the past decade…. for Sen. Shelby.

    87 yr old Shelby is not seeking re-election this year (2022), but his staffer Katie Britt is the GOP nominee. No mention of NASA on her campaign website.

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