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Thread: SpaceX BFR/BFS SuperHeavy vehicles (space jogging?)

  1. #16
    Super MURCer cjolley's Avatar
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    It's not the structure I wonder about. It's the reactivity of Lithium or Aluminum holding pure Oxygen. Do they line them with something for that use?
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  2. #17
    Super MURCer Fat Tone's Avatar
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    Didn't Musk say there were hoping not to have to use a liner, subject to pressure-test results?
    FT.

  3. #18
    Super MURCer cjolley's Avatar
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    That just sounds like a terrible idea if the tank is Lithium. And that may also apply to Aluminum.

    https://www.youtube.com/watch?v=Mtb87I3xKUU
    Chuck
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  4. #19
    Moderator Dr Mordrid's Avatar
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    VJ: that study was poorly done. They exposed the rats to a high single dose equivalent to a Mars transit dose, then waited for changes. This kind of test assumes Linear No Threshold, that there is no safe dose at the lower end, which save for US govt. labs has been discredited - even by WHO. There is a low threshold where DNA repair and other mechanisms allow tissues to recover from lower level radiation doses over time. This is in part why critters survive so well around Chernobyl. There are also anti-radiation pharmaceuticals which mitigate acute radiation syndrome. DHS has them stockpiled.

    The vehicle will be mostly carbon composite, built with the help of Janicki Industries in Washington State. They've done aerospace and DoD work; Boeing 787, B-2 bomber, F-22, F-35, NASA's Space Launch System and the upcoming B-21 Raider bomber/interceptor. And a few black projects. They'll also set up shop in a customers facility.

    Lithium-Aluminum tanks work just fine in rockets; LOX, H2, whatever. Falcon 9 and several others use it; all that's needed is the normal aluminum oxide coating, or if you're paranoid a chromate coating. Industry standard.

    The ITS spaceship carbon composite tank, which is also structural, uses a polyurethane matrix - which allows for cryogenic temps without micro-cracking. They're testing the bare surface, which is what NASA and Boeing used a few years ago with LOX and hydrogen, but are also looking at spray-on coatings or, as a last option, a thin Invar lining. Invar is an alloy which has a very stable expansion coefficient at cryogenic temps. They would form the liner on the tank mandrel, then wrap the composite over it.

    Even using a composite structure the ITS first stage will mass 275 metric tonnes dry.

    Soon they'll put that beast of a tank on a barge, take it out to sea and pressurize it to 67% of burst pressure. Don't want that failing in a populated area.

    For solar radiation they'd do the transit with the vehicles tail pointing to the Sun, using the entire bulk of the engines, tanks, engineering and cargo sections to shield the cabin from solar radiation. Galactic cosmic rays aren't so much of a concern with the high deltaV fast transits they plan on using. Additionally, cosmic rays are minimized during high periods of solar activity, deflected by the solar magnetic and electric fields of the solar wind. Borated polyethylene (lots of hydrogen, like water) can shield the walls from radiation and neutrons. Borated polyethylene is a standard shield in high energy radiation therapy and increasingly in aerospace. Z-shields, multiple layers of increasingly dense metals, are also very effective.

    THIS IS HAPPENING, and modded versions of the spaceship could serve as a single stage to orbit (SSTO) launcher or a Mach 20 point-to-point transport.
    Last edited by Dr Mordrid; 28th October 2016 at 13:36.
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  5. #20
    Super MURCer MultimediaMan's Avatar
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    Quote Originally Posted by cjolley View Post
    That just sounds like a terrible idea if the tank is Lithium. And that may also apply to Aluminum.

    https://www.youtube.com/watch?v=Mtb87I3xKUU
    You're not wrong... it is a dangerous mix. But, in the end, it's no worse than the LoX if it burns (it's not like you have anything to extinguish it with once the candle is lit). One thing about Metallic Lithium and Aluminium bladders is that they aren't ~just~ one material. Lithium and aluminum form hard oxide layers after manufacture (both can take weeks to develop a "skin"); generally they accelerate this process by a simple annealing process in air. In the case of aluminum, that layer can be fairly deep (almost 0.002"); both metals can be anodized which can further seal and protect the underlying metal (at the cost of some embrittlement).

    Rockets are designed with very narrow material margins as compared to aircraft, and they are subject to different risk analysis scenarios which account for why they are built relatively "suicidally"... they have to be; overbuilding a rocket by even a kilogram is a lot of wasted money per launch.

    Example: The tank tests slated for these things. ASTM standards for pressure vessels are to build in a 400% safety factor. Yet, these rocket engineers have designed this tank with only a 33% (designed) safety factor and no one is complaining, because it wouldn't be practical for a space vehicle if they built it to ASTM standards. A lot of engineering "violations" occur in aerospace, racing and even a number of fairly common past times (bicycling comes to mind). They routinely trade long-term strength and durability for light weight, and shorter effective lifespans. We see it in CPUs and graphics cards all the time...overclocking is simply removing the conservative engineering controls to favor speed instead of reliability and longevity.
    Hey, Donny! We got us a German who wants to die for his country... Oblige him. - Lt. Aldo Raine

  6. #21
    Moderator Dr Mordrid's Avatar
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    Quote Originally Posted by Dr Mordrid View Post
    >
    Soon they'll put that beast of a tank on a barge, take it out to sea and pressurize it to 67% of burst pressure. Don't want that failing in a populated area.
    >
    12 meter LOX tank test #1 done on a barge off the harbor at Anacortes, Washington.

    Reddit thread....

    Thought you might enjoy some pictures I took. Yes, my camera is a potato.

    A few years ago one of the large manufacturing buildings in our small town got bought by a bunch of strange suits, supposedly by Boeing for special projects. Extremely tight security.

    Even the shipping containers outside had biometric locks on them.

    But yesterday they brought this thing out and loaded it onto a barge, supposedly for "destructive testing".

    Less than 24 hours later, it has already returned seemingly intact.

    They could not have gone very far at all, so everybody around here is pretty curious about what they actually did.

    I saw a few man-sized silver tanks that were being moved off the barge as well, which were also venting.
    UNLOADING






    Testing timeline


    And a pic showing the Heart of Gold-class spaceships size compared to ISS

    Last edited by Dr Mordrid; 11th November 2016 at 20:50.
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  7. #22
    Super MURCer Wulfman's Avatar
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    Don't you normally do burst tests using water? Not much happening if it goes boom. But hey, I guess if they have to test the behavior under cryogenic conditions...
    "Perhaps they communicate by changing colour? Like those sea creatures .."
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  8. #23
    Super MURCer MultimediaMan's Avatar
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    Quote Originally Posted by Wulfman View Post
    Don't you normally do burst tests using water? Not much happening if it goes boom. But hey, I guess if they have to test the behavior under cryogenic conditions...
    Ding Ding Ding, we have a Winner: You have to do it at temperature. I am absolutely certain the tank has already undergone Hydrostatic testing, cryo-soak test is a more of a materials stability test rather than an ultimate strength test.
    Hey, Donny! We got us a German who wants to die for his country... Oblige him. - Lt. Aldo Raine

  9. #24
    Moderator Dr Mordrid's Avatar
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    And news from the NASA front

    Trump is restarting the National Space Council, which seems an attempt to short circuit Shelby in the Senate and the House Lockheed-Boeing caucus.

    NASA has also issued an RFI whose end result would be mothballing the Orion deep space vehicle, and likely SLS, after their first flight. This in favor of "commercial options." The commercial vehicles which are intended for or upgradeable to deep space would be Crew Dragon (much already done for the Red Dragon Mars flights starting in 2018), CST-100 Starliner, Blue Origin's SV and the elephant in the room - ITS.

    Lockheed (Orion) issued a statement they could lower costs 50%, but that doesn't do a thing about the costs of a disposable SLS.

    Fur gonna fly....
    Dr. Mordrid
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  10. #25
    Super MURCer MultimediaMan's Avatar
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    If they stay focused on the money (and they likely will), NASA will be nothing more than a travel agent. Which is bad, given NASA's charter. What NASA should do is have a clause to "open source" technologies as condition of participation; Elon already does it. If the Rest of the Aerospace contractors did there would be competition based on efficiency rather than a Technical Expertise/NDA/Intellectual Property firewall, and allow "small fries" to disrupt.
    Hey, Donny! We got us a German who wants to die for his country... Oblige him. - Lt. Aldo Raine

  11. #26
    Moderator Dr Mordrid's Avatar
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    The SpaceX-USAF contract for a Raptor upper stage engine by the end of 2018 (sea level Raptor is already on the stand) specifies Raptor be made available to other companies flying USAF payloads under the EELV program. This would mean ULA's Vulcan methane/LOX launcher could use either Blue Origins BE-4 or SpaceX's Raptor. If there's a problem with one fly the other.

    That said, Raptor is smaller, lighter, has a higher Isp and is more powerful. Full Flow Staged Combustion with a chamber pressure of 30 MPa (4,400 psi). Wicked.
    Last edited by Dr Mordrid; 13th November 2016 at 21:00.
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  12. #27
    Moderator Dr Mordrid's Avatar
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    At IAC 2017 the BFR Booster (aka BFB) and BFR Spaceship (aka BFS) were rescoped to a 9 meter diameter with 31 sea level Raptor engines in BFB and a mix of 4 vacuum and 3 sea level Raptors on BFS.

    The USAF vacuum Raptor is due for delivery to the Air Force in December, and tests have been ongoing at the McGregor test center since September 2016.

    The vehicle redesign keeps a 150 tonne to LEO lift, up to 100 passengers in the BFS, and the ability to be reconfigured as a propellant Tanker or Cargo ship.

    It's also configured to be a satellite deployer to replace both Falcon 9 and Falcon Heavy, and for Point-2-Point human and cargo intercontinental transportation. FAA and DoT are exploring what regulatory frameworks will be needed.

    BFB+BFS= 348 feet long, and a very second factory build at the Kennedy Space Center is in negotiations between SpaceX, Space Florida (state agency) and the USAF.

    Progress

    This weekend Musk appeared at SXSW in Austin Texas. Musk gave a long interview with buddy Jonathan Nolan (writer Interstellar, Batman Begins/Dark Knight, brother of director Christopher Nolan) delivering questions.

    "Mars is really about getting the spaceship built. We are making good progress on the ship and the booster. That design is evolving rapidly. We are actually building the ship part now. Once we build it, we will have a point of proof.
    >
    People have told me that my timelines historically have been optimistic. I am trying to recalibrate. What I do know is we are building the first ship. We will be able to do short flights in the first half of next year. It's a big booster and ship. Saturn V thrust x2.
    >
    A BFR flight will cost less than the Falcon 1. It will be less than $5-6 million per flight.







    Satellite deployer: 'Chomper' concept
    Last edited by Dr Mordrid; 12th March 2018 at 22:13.
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  13. #28
    Moderator Dr Mordrid's Avatar
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    Wow....

    "Shotwell" = SpaceX President Gwynne Shotwell, a steely-eyed business-woman & one of the best execs in aerospace.

    Caleb Henry writes for Space News

    Caleb Henry @CHenry_SN
    SpaceX's Shotwell: BFR will probably be orbital in 2020, but you should start seeing hops in 2019. (Gras*hopper reference?) #satshow
    4:34 PM - Mar 12, 2018

    https://twitter.com/CHenry_SN/status...037969408?s=19
    Last edited by Dr Mordrid; 12th March 2018 at 22:17.
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  14. #29
    Moderator Dr Mordrid's Avatar
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    Composite layup tool for the BFS Spaceship's hull.

    Tesla Model 3 for scale.

    Filament winding construction, and it looks like the big tent NSF spies saw going up near Port of LA is indeed the temporary factory. The full factory's construction on Port of LA's Terminal Island is imminent.

    https://www.instagram.com/p/BhVk3y3A0yB/

    Dr. Mordrid
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  15. #30
    Moderator Dr Mordrid's Avatar
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    Teslarati.com is on the case, and SpaceX is no longer using Janicki Industries in WA. They bought the tooling from Ascent Aerospace Coast Composites of Santa Ana, CA. Ascent is another major aerospace composites outfit.

    Construction in the large steel-framed "tent" because they want to get started before the permanent factory is ready next year.

    https://www.teslarati.com/spacex-bfr...site-activity/

    >
    Hours after SpaceX CEO Elon Musk revealed the first photos of tooling for the manufacture of BFR, Teslarati photographer Pauline Acalin sped down to Port of San Pedro to survey a large dockside tent the company was constructing as of December 2017. Now complete, the temporary facility appears to be exploding with SpaceX activity as the company surges ahead with plans to assemble the first Mars rocket and spaceship prototypes rocket-powered hops could begin as soon as early next year, with orbital launches following about a year after that.

    Per a number of related discoveries, the tooling pictured in Musks teaser is almost certainly located in the same tent pictured above. Of particular note, a source involved in the work has confirmed that SpaceX is using a new supplier for the custom tooling needed to manufacture BFR. The sources comments were confirmed to be accurate minutes later in photos taken by Teslaratis senior SpaceX stalker that peg Ascent Aerospace Coast Composites as the tooling manufacturer. As if to dispatch any lingering doubt, Ascent Aerospace appears to have also independently confirmed its involvement through a rare post on social media.
    >
    Last edited by Dr Mordrid; 9th April 2018 at 19:05.
    Dr. Mordrid
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