• Content Count

  • Joined

  • Last visited

Posts posted by RCgothic

  1. If Orion and SLS proofed into non-existence *today*, but the goal of a landing in 2024 and budget remained, NASA could have an HLS style contest to modify a capsule for EOR based on rendezvous with a full upper stage and be no further behind than they already are with the lander contest.

    (Orion was designed to have all its load on the docking port. That's how Altair was originally supposed to send it to TLI.)

  2. High Lunar Orbit is not by itself interesting for humans. It's a step away from LLO, which is a step away from a landing. Two steps away from interesting for humans.

    Anything done in HLO or equivalent is simply makework as that's the only place SLS Orion can go.

    If you're designing a rocket to conduct a lunar landing, you either make it capable enough to co-manifest a lander all in one launch, or you embrace rendezvous. SLS/Orion falls into this awkward middle way where it can't do an all up mission by itself and can't really serve as an earth departure stage for anything other than Orion either. It depends on rendezvous with smaller commercial partners (which weren't available at its inception, so it lucked out there), when it would have been more useful dedicated fully to large payload and earth departure for EOR than half to a mandatory capsule.

    Worse, if your ultimate ambition is to go to Mars (as SLS has always been mentioned in tandem with since its inception), then SLS has very little to contribute to construction of a mothership. Flight cadence is just too low.


  3. I have't seen anything substantaited against Eric Berger, as far as I can tell it's semi-libelous sour grapes from SLS supporters. A popular science editor of a popscience website is not required to be friendly towards a bad system.

    We can all add appropriations and divide by usefulness accomplished, Eric's not the only one lamenting SLS's opportunity cost. NASA Spaceflight stream gave SLS such a kicking earlier.


  4. Yeah, it doesn't matter how much of the money given to AJR is for R&D and retooling or whatever, and what proportion is actually spent on constructing RS25Es and RS25Fs, bottom line is number of units out the door divided by appropriations.

    16 engines refurbished at $127m each.

    6 engines at $193m each to recertify and restart production.

    18 engines at $100m each.


    That's $134m each unless and until they buy more. ($150m each if you include the refurbished RS25 original purchase price, but given some of these may have gotten value from previous missions flown that may be unfair.)

  5. 29 minutes ago, Barzon said:

    Why would Jim Bridenstine, the NASA administrator himself lie about the cost, and say SLS is 800-900 million per launch. If he says that's the cost, you can sure as hell trust him.

    I also like Jim Bridenstine and I can just about see how excluding R&D and fixed program costs $900m might be the marginal cost to build an extra SLS each year.

    RS25s for flight 10 (excluding earlier, higher cost engines) are $100m each.

    SRBs $50m each.

    ICPS $200m.

    Core stage (excluding engines) $200m.

    That's $900m.


    But the program as a whole costs $2B per year and will cost that amount whether or not an SLS gets built. If two get built, that would be $2.9B per year if the $900m marginal cost is accurate, but I'd be extremely surprised if we ever see 3 core stages in a year due to manufacturing capacity limitations.

    You also have to consider the R&D costs to date $15B so far.

    So a reasonable estimate to 2030 is ten flights (as the engines have been purchased) for $35 to $39B. The actual cost as opposed to the marginal cost is therefore likely to be $3.5B to $3.9B each.

    If SLS gets cancelled after 2025 and five flights then it will have cost in the region of $5B per flight.


    And ok, as the timeline goes on and more flights happen the cost does eventually converge (at 2 flights per year and infinite flights) at $1.45B each. 

    But in the same timeline Superheavy, New Glenn, Vulcan, Falcon Heavy will all be flying at at maximum 1/4 as much cost and far more than 1/4 the payload, flying commercially the missions that SLS/Orion should have been flying inclusive if it had just been designed a little larger and more capable, and people will look at that and go:

    "Well this is how we should have been doing it from the start."

  6. 17 minutes ago, tater said:

    The cost of an SLS launch is the cost of the annual SLS program, plus any marginal costs, divided by the number of launches that year. 

    For publically funded missions I'd take total appropriations divided by number of missions (inc cancellations not transferred). Doesn't exclude any R&D costs, years with no flights, or unused hardware.

    Saturn V? $42Bn in 2019$ for 16 missions. $2.7B each.

    Crew rating Falcon 9 and dragon R&D? $3.4Bn over 9 missions. $378m each.

    Commercial Resupply Services? $1.6B for 12 flights. $133m each.


    This way there can be no argument over who got what.

  7. 6 minutes ago, Barzon said:

    SLS is ~900 million per launch, and FHe is ~200m

    Falcon Heavy is $95m reusable to $150m expendable.

    SLS, if it flies 10 times by 2030, will have cost $3.5B to $3.9B each. There is no way it will ever cost as little as $900m.

    All up appropriations for SaturnV was $2.7B each in similar dollars btw.

  8. I think they had two Abort TranOceanic sites for each flight. An article I shared a few pages back was a flight director talking about having to make the weather call for shuttle re-entry and how they had to be as sure as possible what the weather would be at the landing site in 2h time because once the call was made there was no going back!

  9. 1 hour ago, magnemoe said:

    is it that heavy? Anyway the need for an shallow launch trajectory so you can survive an abort, starliner has the same issue but here it was low trust on upper stage with one engine. 

    9.5t empty, 1.3t props, up to 6t Cargo = 16.8t, exactly the same as Starlink.

  10. 2 minutes ago, RealKerbal3x said:

    If the static fire does happen today, then the 150m hop will hopefully happen within a few days :D

    Speaking of static fires, I wonder if this one will be another 2 or 3 second burn, or a longer-duration static fire.

    I don't think the pad can endure a longer burn. They'll need to build something studier for testing superheavy!

  11. High chance of Starlink scrub on Monday. F9 can't land in a tropical storm and SpaceX fleet are seeking cover. SpaceX aren't going to intentionally dispose of their flight leader whilst rigged with landing legs and grid fins for an internal mission nobody's paying them for.