back to article Northrop Grumman to polish NASA's HALO, techies test tardy telescope tower, SLS boosters ready for Florida

NASA's Gateway edged a little closer to reality last week as the agency took another look at the James Webb Space Telescope's launch date and prepared for the arrival of the solid rocket motors for the SLS. Northrop Grumman handed design and development contract for first NASA Gateway module Northrop Grumman is to execute the …

  1. John Robson Silver badge

    An *extra* boost?

    Sea level thrust is approximately (units in kilo-pounds)

    375 klb per SSME

    2,800 klb per booster

    Even with 4 SSME rather than three the SRBs are still doing the vast majority of the work... not just providing "extra"

    Comparing it with the Atlas5...

    Main core: ~860klb

    SRBs: ~285klb each (from zero to 5 available)

    There the boosters are helping with "extra" thrust

    1. KarMann Bronze badge


      [T]he twin boosters generate 3.6 million pounds of thrust each…. The pair will provide more than 75 per cent of the total SLS thrust at launch.

      In the core-burning solid rocket motors (which I believe is very much most of them), adding 25% to the length adds 25% to the thrust, approximately, unless you change the shape of the interior to make it burn faster or slower. Since 3,600 klbf is very nearly 125% of your 2,800 klbf, it sounds like it's the same shape inside.

      Or, you could've just skipped the working out, and taken their 75% figure at face value. OK, I just might like working it out myself and double-checking, too. Assuming their figures for booster thrust and yours for SSME are correct, it's actually 83% booster, which is indeed 'more than 75 per cent,' but I would have thought was worth using something closer, like ⅚ of the thrust.

  2. Youngone

    Northrop Grumman

    Northrop Grumman are not really in the business of doing this sort of design and development.

    What they are really for is to turn American taxpayers money into shareholders money and they're really good at that

  3. Chairman of the Bored Silver badge

    I thought...

    ...the tweet said we were going to put boobs on the moon in 2024. But we think that was a typo

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