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RCgothic

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Posts posted by RCgothic

  1. It's not the oversight I have an issue with. Obviously there needs to be a regulator. And the fact Space X breached the terms of its launch license for SN8 should be expected to have consequences.

    But...

    A basic level of timeliness ought to be expected. Everyone knew before Friday that a scrub would likely mean a backup day of Monday. This wasn't hard to predict.

  2. 2 hours ago, RyanRising said:

    They aborted a flight just after ignition on March 3 (then turned around and flew that same day!) so that probably counts as a static fire. ‘Twas static and the engines fired.

    That's probably what I was thinking of. Thanks!

  3. Gantry crane is *finally* installed!

    Honestly expected it be installed last October. I wonder if this was the major hold up for Superheavy production, or if it just got downgraded to a lower priority relative to more starships?

  4. Gateway's core elements are going up on Falcon Heavy.

    And there is no large surface element that isn't going to have to go down on HLS, which will be commercially launched.

    So which large elements would SLS be pre-positioning exactly, at maybe one flight a year and an unreasonable cost per flight?

    From where we are now there's no sensible use case. Falcon Heavy and Commercial Crew changed everything.

  5. 21 hours ago, RCgothic said:

    They do like to milk the "SLS is the most powerful rocket ever" propaganda. It's not.

    SLS will, assuming Superheavy doesn't fly with at least 14 engines before next February, briefly hold the title of most thrust at liftoff of any rocket ever.

    Haha, wait, N1 had massively more thrust than SLS at liftoff!

    Nope, genuinely can't think of a metric under which SLS is most powerful without some sort of qualification.

  6. Well Wikipedia also defines Saturn V as "most powerful (total impulse)", so I'm being a little generous to SLS by considering a definition of total impulse to be "total mass accelerated to final velocity, multiplied by velocity", thus including its heavier final stage and saying "arguably", because stages without fuel don't count as useful payload, as rightly pointed out.

    But if block 5 can only manage 45t payload to TLI and EUS weighs around ~15.6t at burnout, that's just 60.6t.

    Saturn V managed 48.5t to TLI and S-IVB weighs 13.5t, then that's about 62t, so SLS won't win even on this metric unless it finds some extra payload somewhere.

     

    Bottom lines:

    Thrust on the pad is not power.

    SLS will probably not have the highest instantaneous power.

    SLS probably won't have most payload to TLI.

    SLS probably won't have highest total mass (total impulse) to TLI.

    SLS will not have most mass/payload to LEO.

  7. 11 minutes ago, tater said:

    Do they claim 60t to TLI on Block 2? With Orion? (cargo TLI mass is better than with Orion presumably because of LES mass combined with a different trajectory compatible with safe crew abort)

    Heck, that's almost useful... not sure what the cutoff is for a lander that also gets stuck with the LOI burn in LLO. I want to say I figured it was closer to 65-70t for the whole stack at TLI.

    That'd be SLS ~48t payload to TLI plus ~15t EUS after burnout ~=63t total.

    Saturn V was ~60t to TLI including S-IVB.

     

    Of course Saturn V sent over 48t payload to TLI as well, so in terms of useful work done it'd still be a tossup. It's just that S-IVB is lighter. Hence the argument.

  8. They do like to milk the "SLS is the most powerful rocket ever" propaganda. It's not.

    SLS will, assuming Superheavy doesn't fly with at least 14 engines before next February, briefly hold the title of most thrust at liftoff of any rocket ever.

    Most powerful (total impulse) is still Saturn V.  60t total to TLI can't be argued with until Block 2, if that ever happens.

    Most powerful (instantaneous power) is probably also Saturn V.  Thrust times velocity, I'm pretty sure S-IC is producing more power at centre engine cut off and outboard-engine cutoff than SLS is at BECO. SRBs have a vaguely decaying thrust profile.

    And Superheavy is rapidly arriving to take all of these titles for itself if SLS doesn't hurry up.

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