Monday, March 15, 2021

As SLS Green Run Re-Test Approaches, NASA Investigates the Program

This Thursday, March 18, NASA's Artemis program has scheduled the re-test of the Space Launch System (SLS) core stage, the test they call the Green Run, to qualify the vehicle for its first unmanned test flight.  The test will be at Stennis Space Center in Mississippi.  This re-test is due to the problem they had with the first test in January, when the vehicle software aborted the test at 67 seconds into a targeted 480 second test.  I wish them luck in their test.  Better yet, I wish them absolutely rock hard competency, something that seems to have been missing. 

It's interesting that word is leaking out in advance of this test that the new Biden administration has begun a study of the affordability of the program and whether or not to continue it.  The analysis is being led by Paul McConnaughey, a former deputy center director of NASA's Marshall Space Flight Center in Huntsville, as well as its chief engineer.  McConnaughey is working under Kathy Lueders, NASA's chief of human spaceflight, whose last job was directing the commercial/NASA partnership that's approaching the one year anniversary of the first commercially conducted manned launch.
The SLS rocket program has been managed by Marshall for more than a decade. Critics have derided it as a "jobs program" intended to retain employees at key centers, such as Alabama-based Marshall, as well as those at primary contractors such as Boeing, Northrop Grumman, and Aerojet Rocketdyne. Such criticism has been bolstered by frequent schedule delays—the SLS was originally due to launch in 2016, and the rocket will now launch no sooner than 2022—as well as cost overruns.

For now, costs seem to be the driving factor behind the White House's concerns. With a maximum cadence of one launch per year, the SLS rocket is expected to cost more than $2 billion per flight, and that is on top of the $20 billion NASA has already spent developing the vehicle and its ground systems. Some of the incoming officials do not believe the Artemis Moon Program is sustainable with such launch costs.
I know I've quoted a lot of these facts before but the prices of the SLS are stunning.  The SLS is using 4 of the Space Shuttle Main Engines, the RS-25.  These are excellent engines and probably have the most thorough documentation of their history of any rocket engine, an engine so good it has been called the Ferrari of rocket engines.  I'm not knocking the SSMEs.  The problem though, is these engine have been costed out at $146 Million a piece, or just shy of $600 million for the engines alone on one flight.  Engines that will be thrown in the Atlantic when the core stage is done.  When Rocketdyne was selling them to the Shuttle program they were $40 million as reusable engines.   

The published thrust in a vacuum of the SSME is 512,000 lbs. The stated thrust of the SpaceX Raptor v2 is 500,000 lbs.  OK, similar performance with the edge to the SSME.  The target cost at production of the Raptors is $250,000.  That's not even two thousandths (0.0017) of the cost of the SSME, or 0.17% if you prefer.  The current generation of Raptors, as they work toward that $250 thousand price is around $1 million.  That's still stunningly less than $146 million.

$146 million for the engines alone is similar to the price of a mission on a Falcon Heavy with reused boosters.  Powered by the smaller and less powerful Merlin 1D engines, the Falcon Heavy has two-thirds the lift capacity of the Space Launch System at one-twentieth the price.

These are the kinds of things that the NASA study will be facing.  Even before the study's initiation, Study Lead McConnaughey had been pushing for the SLS program to become more cost-effective. One goal of this analysis is to find ways for the large NASA rocket to compete effectively with privately developed rockets as part of the agency's Artemis Moon program.

The real wild card here is Starship.  SpaceX is continuing the Starship Launch System test campaign, as we talk about regularly.  SpaceX has said they intend to make its first orbital flight by July 1 of this year; that may be Elon Standard Time, but it seems likely it could be between July and the end of the year.  This is a launch vehicle that could potentially out-lift the SLS rocket, be reusable, and cost a fraction of the price. If SpaceX succeeds in getting Starship into orbit, how could NASA justify continuing government subsidization of the less capable SLS booster, which is expendable and costs much, much more.  

Of course the main contractors on SLS don't believe SpaceX can do it.  To me, there doesn't seem to be much profit in betting that SpaceX can't accomplish things they say they will.

NASA Artist's Concept of SLS.


  1. I'd never read any of the pricing for the components until you posted this. I instinctively knew the SLS would be far more costly, but the way you put it, I think that program should be terminated if they can't cost control it say, an order of magnitude cheaper?

    We may be witnessing the beginning of the end of "Big Aerospace".

    1. It's nearly a crime to continue the SLS in the face of its competition. What I'd like to see is a breakdown of WHY the cost of SLS is so much higher. Is there an infrastructure cost that SLS (as opposed to a jobs program/welfare for the middle class) carries that SpaceX does not? I don't see it, but it may still be there.

  2. SLS in the air: Zero.
    Musk in the air: Lots.

    If I were betting . . . this is a slam dunk.

  3. Sad thing is... I do believe that the SLS may be flight tested before New Glenn or the Vulcan rocket using the BE4 engines.

    There is no reason for using SSMEs, never has been. A 'chimp' version of the SSME, dumned down to remove all the 'reuseable' stuffs that make it such an expensive and complicated engine, makes sense. Kind of like what NASA looked at in the F1B, where the bazillion components and manufacturing steps of the F1 were shrunk down to 100ish modern CNC and 3D printed components.

    The COTS program was such a great thing for NASA. It's time, past time, to extend the same forward thinking into the SLS program.

    Yes, I like having a national space launcher. Just not a bloated whale of a subsidized POS like the SLS. Same reason I love what SpaceX has done to ULA. (And isn't it amazing how quickly ULA got off their bloated butts once SpaceX started kicking them hard in the profit margin?)

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  5. Just another example of , "cost is no object" when the taxpayers are on the hook.

    Whitehall, NY

  6. I think that this may be the best post on why this boondoggle is past time for cancellation. I had high hopes back when it was Aries, but I think my goodwill was misplaced.

    1. One of the comments to the article on Ars Technica hit my funny bone with this:

      "Saved 'em a bunch of time and money:

      The affordability is shit, the program is shit, and the contractors are shit. You could literally pay everyone their current salary directly to not do their job, and have enough savings to pay SpaceX to lift all this shit to orbit"

      Don't know for sure that it's true, but it seems like it.

      HOWEVER ... I just got back from reading that entire blog post. It's not a light read, but it's fantastic. Recommend it to anyone. And I take back everything nice I said about RS-25 SSMEs.

    2. Casey writes:

      I'm 100% okay with Congress cutting generous checks to politically important constituencies to develop hardware for human space exploration

      'I hate the result, and I want to keep doing exactly the process that produced this result!' Casey is avoiding reality just like NASA does. He's a religious nut; he will do anything to avoid admitting his savior government rarely functions as advertised.

      After the dollar hyperinflation removes power from voters who are 100% okay with Congress cutting generous checks to politically important constituencies to develop hardware for human space exploration, libertarians will put a resort hotel on the moon in a year.

  7. Didn't AOC have a description of how government affords things, along the lines of "just buy it"?

    Did I read that half of all dollars ever in existence have been created since 2020?

    Yes, they are going to hyperinflate the dollar.

    Tuberculous and Syphilis are two diseases that were once common among the first world population; I see no reason why mental illness couldn't be similarly common. Legislators who will hyperinflate are mentally ill. Voters who believe legislators will never actually hyperinflate are mentally ill. Lots of delusional thinking to go around.

    Portugal, Spain, The Netherlands, France, Britain: Reserve currency status lasts for about 100 years.

    I conclude there is some an oscillator implemented using humans.

  8. The Falcon 9 exists and flies.

    I think SpaceX will have a tough row to hoe with the first stage of their ITS vehicle. People seem to forget that the Starship itself can't make orbit. (Or if it barely can in some technical sense (doubtful, SSTO requires absurdly small structural mass fractions) it can't do it with any payload.) The first stage will have to deal with severe vibration from the engines with an extremely lightweight structure.

    So SpaceX's rocket isn't a done deal yet. I still think they are making progress towards the goal, and have a good track record of making progress towards their goals.


    1. Remember the thinner stainless they were testing in 7.2? Pretty sure it was 3mm instead of 4. I picked up scuttlebutt that they've dropped that idea. It could barely support its own weight.

      The first booster test flight is looking to be in the next few months. It won't have the full complement of engines, but it will certainly be interesting.

    2. PS: SpaceX's ITS not being fully developed doesn't make the SLS a good idea. It's a bad idea on internal design principles alone.

      Just saying that the competition won't be entirely real until bent metal is sitting on a launchpad.