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Thread: US Commercial Crew spacecraft progress: tests & early missions

  1. #16
    Moderator Dr Mordrid's Avatar
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    Crew Dragon static fire video (slo-mo)

    https://twitter.com/commercial_crew/...73732034396160
    Dr. Mordrid
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  2. #17
    Moderator Dr Mordrid's Avatar
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    1) Sounds like Crew Dragon DM2 carries a crew to ISS first. This includes extra crew training.

    Chris G - NSF @ChrisG_NSF
    NASA says they've done everything to allow #DM2 (SpaceX's crew test flight) to stay for a long duration mission on ISS. NASA is just waiting for time to pass as the vehicles work through final certifications for flight. #SpaceX #Dragon #NASA

    https://twitter.com/ChrisG_NSF/statu...80893470109697

    2) Boeing Starliner scheduled its OFT (orbital un-crewed) test flight for December 19 at 0659 Eastern. This delayed from December 17 because of a problem with the Atlas V N22* rocket

    * N22 = No fairing, 2 solid boosters, 2-engine Centaur upper stage
    Dr. Mordrid
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    An elephant is a mouse built to government specifications.

    I carry a gun because I can't throw a rock 1,250 fps

  3. #18
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    Crew Dragon schedule alert!!

    Stephen Clark @StephenClark1 (SpaceFlightNow)
    Hello from Hawthorne. Got to see the Dragon for the Demo-2 crewed mission. SpaceX aims to ship it out of factory by the end of year for thermal vacuum testing. Gwynne Shotwell says the target date for the in-flight abort test is Jan. 4. She says Demo-2 as soon as February.

    https://twitter.com/StephenClark1/st...28237364105217
    Dr. Mordrid
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    An elephant is a mouse built to government specifications.

    I carry a gun because I can't throw a rock 1,250 fps

  4. #19
    Super MURCer UtwigMU's Avatar
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    Von Braun -> John Glenn = 17 years
    Space shuttle -> now >= ~9 years

  5. #20
    Moderator Dr Mordrid's Avatar
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    Some say it should have only been 7 years, but in doing that the nitrogen tetroxide/titanium incomparability discovered during the DM1 test fire may not have been discovered. NASA's already looking at it as a possible cause of some unexplained failures.
    Dr. Mordrid
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  6. #21
    Super MURCer MultimediaMan's Avatar
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    Titanium is a fairly reactive metal. When I worked for Pratt and Whitney, there were many solvents which couldn't be within 3 Feet/ 1M of titanium, Trichloroethane was one of them, Tri-Sodium Phosphate was another. Nitrogen Tetroxide's reactivity with Titanium has been known since the 1950's. What is new is that "printed" and Metal Injection Molded are somewhat unpredictable with how they interact in these acidic/basic environments (with their fairly amorphous structures) and with the binders which are used to make the base material more formable. Right now, a lot of research is going on to artificially age Printed and MIM parts and see how they change over time, structurally and chemically. Right now, MIM has some fairly strict part size limits, but as technology marches on, the parts will get ever-larger, and as they do these research projects will be crucial to determining the suitability of metal Printing/MIM processes for ultimate durability.

    Case in point: Phosphoric Acid (Naval Jelly) will reduce iron and steel parts made with the Metal Injection Molding process to crumbly bits in a few hours, where conventional cast and forged parts are virtually invulnerable to Phosphoric Acid after a few minutes (after the Phosphoric Oxide forms). The mechanisms that make the damage possible in MIM are a result of manufacturing process itself... the binders make the base metal more porous, and often have (many, many) layers of oxides which the acid can attack.
    Hey, Donny! We got us a German who wants to die for his country... Oblige him. - Lt. Aldo Raine

  7. #22
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    AIUI, the old paper noted NTO/Ti flammability, but they found it wasn't self-propagating at thruster line pressures. Apparently they didn't test at the pressures used in the SuperDraco pressurization system. When a slug of NTO leaked into that line and it was pressurized during SD startup, the slug slammed into the Ti valve and <boom>.
    Dr. Mordrid
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    An elephant is a mouse built to government specifications.

    I carry a gun because I can't throw a rock 1,250 fps

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