Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Latest Test of RS-25, engine that powers SLS

Comments

  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,538 Mod ✭✭✭✭Capt'n Midnight


    So how is this so different to the space shuttle main engines that it's newsworthy as anything other than PR to justify the exorbitant costs ?


  • Registered Users Posts: 425 ✭✭Mathiasb


    So how is this so different to the space shuttle main engines that it's newsworthy as anything other than PR to justify the exorbitant costs ?

    This:
    pace Launch System[edit]
    A diagram showing the configuration of a Space Launch System rocket consisting of an orange first stage with a cluster of RS-25s at its base and flanked by two solid rocket boosters. This stage is topped with a white second stage and several measurements are indicated. See adjacent text for details.
    NASA's SLS reference configuration from February 2011.
    On the Space Launch System (SLS), new expendable versions of the engines are planned once the initial inventory of SSME engines from the Shuttle program are used up. The development of cheaper expendable versions of the engine has a long history, most notably proposed in the 1990s with the National Launch System (NLS).[45][46] The SLS's expendable RS-25, in clusters of three, four or five, is being studied; each draw their propellant from the rocket's core stage. They provide propulsion during the first stage flight of the SLS, with additional thrust coming from two boosters. Following staging, the engines are discarded along with the rest of the core stage.

    Following the retirement of the Space Shuttle, NASA announced on September 14, 2011, that it would be developing a new launch vehicle, known as the Space Launch System (SLS), to replace the shuttle fleet.[47] The design for the SLS features the RS-25 on its core stage, with different versions of the rocket being installed with between three and five engines.[48][49] The initial flights of the new launch vehicle will make use of flown Block II RS-25D engines, with NASA keeping the remaining such engines in a "purged safe" environment at Stennis Space Center, "along with all of the ground systems required to maintain them."[50][51] In addition to the RS-25Ds, the SLS program will make use of the Main Propulsion Systems from the three remaining orbiters for testing purposes (currently being removed as part of the orbiters' decommissioning), with the first two launches (SLS-1 and SLS-2) possibly making use of the MPS hardware from Space Shuttles Atlantis and Endeavour in their core stages.[49][51][52] The SLS's propellants will be supplied to the engines from the rocket's core stage, which will consist of a modified Space Shuttle external tank with the MPS plumbing and engines at its aft, and an interstage structure at the top.[6] Once the remaining RS-25Ds are used up, they are to be replaced with a cheaper, expendable version, currently designated the RS-25E[6] ('E' for expendable).[dubious – discuss] This engine may be based on one or both of two single-use variants which were studied in 2005, the RS-25E (referred to as the 'Minimal Change Expendable SSME') and the even more simplified RS-25F (referred to as the 'Low Cost Manufacture Expendable SSME'), both of which were under consideration in 2011.[32][53]


  • Closed Accounts Posts: 2,050 ✭✭✭nokia69


    cost aside it will be an excellent rocket

    I expect it to fly a few times and then get cancelled


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,538 Mod ✭✭✭✭Capt'n Midnight


    http://spacecraft.ssl.umd.edu/akins_laws.html
    39. Any exploration program which "just happens" to include a new launch vehicle is, de facto, a launch vehicle program.

    39. (alternate formulation) The three keys to keeping a new manned space program affordable and on schedule:
    1) No new launch vehicles.
    2) No new launch vehicles.
    3) Whatever you do, don't develop any new launch vehicles.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,538 Mod ✭✭✭✭Capt'n Midnight


    nokia69 wrote: »
    cost aside it will be an excellent rocket

    I expect it to fly a few times and then get cancelled
    But will it be any better or cheaper than the stuff they've shelved over the years ?

    And yea there aren't a whole lot of missions that the SLS would be needed for. Look at all the countries that that have demonstrated the capability to dock with the ISS for the altenative of building a craft in orbit using existing off the shelf launch systems. It's one of the options the Russians are looking at for their part of the ISS after it's broken up.

    The disadvantage is that you'd have to use storable propellants which have less energy than the cyrogenic ones. Then again you could also use ion thrusters to set take the fuel sections from LEO into a highly elliptical orbit so you could use the Oberth effect. Not sure of the energetics but it's a bit like a solar powered spaceship. Docking the manned bit would be interesting though.



    I'd be interested to know the break-even point between the supposed savings on a non-resuable version compared to using the original SSME that over life of the shuttle that engine has been tested to orbit 400 times.

    And then consider that a new disposable version would probably use cheaper materials and like debugging a program, chances are they may replace known problems with unknown ones.


  • Advertisement
  • Registered Users Posts: 13,575 ✭✭✭✭josip


    I thought it better to post this here than creating a new thread.

    Only fired for 1 minute instead of the planned 8.

    https://www.bbc.com/news/science-environment-54583588

    Better than nothing or exploding I suppose.
    But this will push the schedules back a bit I imagine.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,538 Mod ✭✭✭✭Capt'n Midnight


    josip wrote: »
    Better than nothing or exploding I suppose.
    But this will push the schedules back a bit I imagine.
    This is essentially an modernised version of engine that made it to orbit almost 40 year ago. - April 12, 1981.

    And by modernised I mean better material, better techniques like 3D printing and more robots and better computers for design and with a much lower design life. The are aren't even reinventing the wheel they already have data from several hundred engine trips to orbit.

    Money for old rope.


  • Closed Accounts Posts: 407 ✭✭tipp_tipp_tipp


    Just saw a quick clip of the test. Pretty impressive even though it ended early. Would love to know more about the rig they're using to test this.


  • Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 90,538 Mod ✭✭✭✭Capt'n Midnight


    Just saw a quick clip of the test. Pretty impressive even though it ended early. Would love to know more about the rig they're using to test this.
    Check out Stennis Space Center where they've been doing full scale tests on those RS-25 engines since March 16, 1977.


Advertisement