TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC
  1. TMC is currently READ ONLY.
    Click here for more info.

Falcon Super Heavy/Starship - General Development Discussion

Discussion in 'SpaceX' started by Grendal, Nov 4, 2017.

Tags:
  1. Bobfitz1

    Bobfitz1 Active Member

    Joined:
    Sep 24, 2012
    Messages:
    1,160
    Location:
    Ludlow, Vt
    It seems plausible to me that the first Starship prototype used to take people into LEO might use a commercial crew Dragon capsule (or major portions of one) mounted inside the cone of Starship. That would enable up to 7 astronauts to reach LEO the soonest, versus designing and building the full size passenger pressure vessel and all associated life support systems production Starship will need for Dear Moon and future moon/Mars manned missions. I can't imagine Elon wanting to delay the first manned orbital flights for the amount of time needed to execute the final crew sections and life-support of the ship.
     
  2. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,857
    Location:
    Michigan
    Interesting.
    Dragon is 3.7 m diameter, Starship is 9m. Could easily stuff one inside, but that doesn't validate the real systems so it's not a real test of Starship.
     
    • Like x 1
  3. adiggs

    adiggs Active Member

    Joined:
    Sep 25, 2012
    Messages:
    4,172
    Location:
    Portland, OR
    Has me wondering - how many Dragons could you fit inside of Starship?

    Then THAT has me wondering - how hard would it be for SpaceX to put a Starship into LEO with a crew on board to do science and stuff, and have it land 6 months later (or 3 or 12 - whatever) while putting another one up? SpaceX - your new provider of Earth orbit space ship and science capability.
     
    • Like x 1
  4. diplomat33

    diplomat33 Well-Known Member

    Joined:
    Aug 3, 2017
    Messages:
    6,832
    Location:
    Terre Haute, IN USA
    I don't see why not. Starship is designed for a long trip to Mars. They could reconfigure the inside with the labs needed for the science experiments and the supplies to maintain the crew.
     
  5. ecarfan

    ecarfan Well-Known Member

    Joined:
    Sep 21, 2013
    Messages:
    19,181
    Location:
    San Mateo, CA
    I may have missed the explanation for this, but does anyone know the purpose of the two stubby “fins”, as indicated in this image? There are no corresponding structures shown on the other side of the vehicle (which is flattened, not a curve) so I assume they do not contain extendable landing legs.

    3F615448-129C-44B6-ABB8-9DEAB2465F03.jpeg
     
  6. bxr140

    bxr140 Active Member

    Joined:
    Nov 18, 2014
    Messages:
    2,607
    Location:
    Bay Area
    I'm pretty sure those are mount points for a total of 6 legs. Its likely that the 'fins' on the underside have a different aerodynamic profile that's a little flatter than the topside ones and thus results in a more manageable thermal gradient during re-entry. (Standout features are what receive the highest thermal loading)
     
  7. miimura

    miimura Well-Known Member

    Joined:
    Aug 21, 2013
    Messages:
    5,971
    Location:
    Los Altos, CA
    I'm just guessing, but it could be interstage connection point reinforcement or in-orbit refueling connection points. As @bxr140 points out, they complete the 6 equally spaced protrusions around the circular cross-section.
     
  8. bxr140

    bxr140 Active Member

    Joined:
    Nov 18, 2014
    Messages:
    2,607
    Location:
    Bay Area
    Also, just had a super 'duh' moment (some might call it an epiphany..) relative to the conversation we had in the Texas thread about the 'enclosed' nozzles, thanks to the image @ecarfan posted. The AOA in that rendering looks like a very shuttle-esque 40 degrees which, as noted in that conversation, would put non-shrouded engine nozzles directly in the atmospheric flow during re-entry. The shuttle follows that same logic, only the engines aren't shrouded all the way around because they don't need to be.

    It is likely the more symmetric skirt on Starship provides more symmetric aerodynamics (and thus more ideal vehicle control) during final descent. There's probably a favorable though less significant benefit during ascent as well.

    [​IMG]
     
    • Like x 2
  9. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,857
    Location:
    Michigan
    From their website : Starship’s forward payload volume is about 1,100 m^3
    The ISS is 916m^3 International Space Station - Wikipedia
    Skylab was: 361 m^3
    MIR was: 90 m^3
    Crew Dragon: 9.3 m^3
    Apollo command module was: 6.17m^3
     
    • Informative x 2
  10. ecarfan

    ecarfan Well-Known Member

    Joined:
    Sep 21, 2013
    Messages:
    19,181
    Location:
    San Mateo, CA
    Wow, great interview, and it was hilarious to see how Elon really did not want to stop talking to Tim about Starship and kept revealing stuff that at least I didn’t know! :p
     
    • Like x 1
  11. FoverM

    FoverM Member

    Joined:
    May 9, 2019
    Messages:
    308
    Location:
    ATL
    No aero-braking, as that gets away from the in-space hardware I'd like to see. Refueling at Mars implies a full operational system in place at the time, so that could include a Mars-LMO system. Regardless, that sort of thing is so far off in the future that you might as well talk about warp drives and transporters.
     
  12. FoverM

    FoverM Member

    Joined:
    May 9, 2019
    Messages:
    308
    Location:
    ATL
    Doesn't really make sense to do that unless you were, somehow, planning on using the capsule for crew reentry. There would be no abort option, no way to easily get into the Dragon, mounting and sustainability issues, etc. I guess you could stick one on the very top ... but that defeats the whole purpose of a crewed Starship.

    AFAIK, we don't even know how a cargo Starship is supposed to release payloads in space. Are there doors, hatches, bays like Orbiter, mouth like the C-5, etc?
     
  13. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,857
    Location:
    Michigan
    See Starship
    Clamshell fairing

    SmartSelect_20191001-215850_Firefox.jpg
     
    • Informative x 1
  14. FoverM

    FoverM Member

    Joined:
    May 9, 2019
    Messages:
    308
    Location:
    ATL
    Looks like they have it all figured out.
     
  15. Bobfitz1

    Bobfitz1 Active Member

    Joined:
    Sep 24, 2012
    Messages:
    1,160
    Location:
    Ludlow, Vt
    You've misunderstood the post's what if premise.
    "It seems plausible to me that the FIRST Starship prototype used to take people into LEO might use a commercial crew Dragon capsule (or major portions of one) mounted inside the cone of Starship."

    The only reason to do so would be if that allowed first Starship manned orbital missions a half or whole year sooner than developing, building and testing the final habitable areas and new life support systems. To send several astronauts into orbit as early as next year, will SpaceX build the final new crew seating setup, control screens, life support for dozens, etc. etc.? Or will they leverage some of what is already built? Elon is in a hurry and thinks out of the box, so temporary workarounds of this sort are possible. Perhaps just use the interior guts of a Dragon 2 inside a pressurized portion of the cargo bay. Or place them inside an inflatable Bigelow module. Just until the interior they have planned is realized.
     
  16. Lasairfion

    Lasairfion Member

    Joined:
    Jul 24, 2018
    Messages:
    491
    Location:
    UK
    Mark 1 and 2 Starships are carrying fuel containers as cargo, essentially. Considering that Elon told Tim that the Mark 3 and 4 prototypes of Starship will integrate the fuel tanks into the walls of the ship rather than have an extra wall, I don't see any chance of a Dragon capsule being used inside. Too much duplication of unneeded weighty parts.

    He stated in the Q&A the night before that the life-support etc was easy stuff.
     
  17. ecarfan

    ecarfan Well-Known Member

    Joined:
    Sep 21, 2013
    Messages:
    19,181
    Location:
    San Mateo, CA
    I’m reviving a post I made about eight months ago to see if anyone has new info on this topic that I might have missed: how will Starship abort and protect the crew if there is a Super Heavy problem during launch and ascent before stage sep? Can the Starship’s 3 sea-level Raptors be used as escape rockets? My guess is they can’t because that would mean their turbo pumps would have to be running and the engines chilled so they would be ready to fire in an emergency (I’m certainly getting some technical details wrong here, so bear with me please) and that is simply not feasible and/or too risky to have those engines in that state during liftoff and ascent.

     
  18. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,857
    Location:
    Michigan
    They can (if prechilled?). Elon comment on this versus SuperDraco type engines:
    SpaceX CEO Elon Musk says Starship pad abort capabilities could come sooner than later
    Elon Musk on Twitter

    abort.PNG
     
    • Informative x 3
    • Like x 2
  19. ecarfan

    ecarfan Well-Known Member

    Joined:
    Sep 21, 2013
    Messages:
    19,181
    Location:
    San Mateo, CA
    Thanks for posting that Twitter thread. Very interesting, so Elon seems to be saying that the Starship Raptor turbopumps can respond fast enough to provide emergency abort capability (though no mention is made of pre-chilling them, but I assume that can be done safely so they are in that state at launch?). So chill the sea-level Starship Raptors just before Super Heavy ignition and they are your emergency abort system. I wonder if all three of them would be used and if one or two would be enough if not all of them ignited in time?

    Super cool (no pun intended). I’m feeling better about my first Starship ride. :D
     
    • Like x 1
  20. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,857
    Location:
    Michigan
    #500 mongo, Oct 3, 2019
    Last edited: Oct 3, 2019
    Yeah, the chilling was my uncorroborated thought.

    To achieve a > 1 thrust to weight ratio, Starship will need all 6 Raptors (2MN each) firing, and probably a less than full fuel load (or payload).
    12 MN = 1350 tons (on Earth). Max fuel load 1200 tons, max payload 100+ tons, ship mass goal ~150 tons = 1450, Space.com says launch weight will be 1,400 pounds.
    Elon Musk Just Dropped More Tantalizing Details About SpaceX's Starship Prototype

    Lunch time, so I'll be lazy and just ask, what is the fuel burn rate for 6 Raptor at 100%?

    At a 330 isp: 4 tons of fuel per second for all 6 raptors.
     

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC