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posted by Fnord666 on Wednesday December 19 2018, @03:18PM   Printer-friendly
from the not-sticking-the-landing-this-time dept.

Submitted via IRC for SoyCow1984

Air Force requirements will keep SpaceX from landing Falcon 9 booster after GPS launch – Spaceflight Now

The demands of launching the first in an upgraded line of U.S. Air Force GPS navigation satellites, including a late load of extra fuel for the spacecraft and a military policy of reserving fuel to eliminate space junk, will keep SpaceX from recovering the first stage of its Falcon 9 rocket following liftoff Tuesday from Cape Canaveral, according to mission managers.

[...] The rocket's first stage will fly without the four landing legs and aerodynamic grid fins used to bring the booster back to Earth intact, according to Lee Rosen, SpaceX's vice president of customer operations and integration. The mission will be the first by SpaceX to dispose of a Falcon 9's first stage since June, and the first time one of the company's new Block 5 boosters has ever been intentionally discarded.

[...] Instead of heading due east from Cape Canaveral, as the Falcon 9 rocket does with most of its commercial communications satellite payloads, the SpaceX launcher will fly to the northeast over the Atlantic Ocean, following a trajectory roughly parallel to the U.S. East Coast. Launching toward the northeast reduces the extra boost in speed a rocket naturally receives from Earth's eastward rotation, meaning it needs to burn more propellant accelerate the GPS satellite into the proper orbit.

Air Force and SpaceX officials cited those factors, along with the weight of the first GPS 3-series satellite — designated GPS 3 SV01 — and "uncertainty" in the Falcon 9's performance to such an orbit, as reasons for deciding to forego a landing of the Falcon 9 booster on Tuesday's mission.

The Air Force also has to comply with a government policy instituted in recent years to avoid leaving spent rocket stages in orbit, and the Falcon 9's upper stage will reignite after releasing the GPS 3 SV01 satellite to target a controlled destructive re-entry back into Earth's atmosphere a few hours later. Mission designers had to set aside some of the rocket's fuel for the de-orbit burn to satisfy the Air Force requirement, which is aimed at preventing space junk.


Original Submission

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  • (Score: 2) by KilroySmith on Wednesday December 19 2018, @03:37PM (11 children)

    by KilroySmith (2113) on Wednesday December 19 2018, @03:37PM (#776339)

    If the satellite and required orbit are at the edge of Falcon 9 capabilities, such that landing legs and grid fins need to be stripped off to lighten the rocket, it seems like a job tailor-made for a Falcon Heavy, recovering all three boosters. It'd be well within the Heavy's capabilities, and recovering the three boosters probably means that it would be cheaper as well.

    • (Score: 2, Interesting) by nitehawk214 on Wednesday December 19 2018, @03:41PM (2 children)

      by nitehawk214 (1304) on Wednesday December 19 2018, @03:41PM (#776340)

      Its possible that later GPS missions will use Falcon Heavy, maybe even double-stack them if they can fit in the payload fairing. But since it hasn't carried a commercial payload yet, the Air Force probably doesn't want the extra risk.

      Throwing away a Falcon 9 is probably still cheaper than Delta IV or Atlas V.

      --
      "Don't you ever miss the days when you used to be nostalgic?" -Loiosh
    • (Score: 3, Interesting) by takyon on Wednesday December 19 2018, @03:55PM (4 children)

      by takyon (881) <takyonNO@SPAMsoylentnews.org> on Wednesday December 19 2018, @03:55PM (#776349) Journal

      The Air Force is one of the initial customers for the Falcon Heavy.

      What we're seeing here is just teething issues.

      Is Falcon Heavy with 3 booster landings cheaper than Falcon 9 expendable? I'd like to compare the numbers if possible.

      --
      [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
      • (Score: 2) by c0lo on Wednesday December 19 2018, @07:46PM (3 children)

        by c0lo (156) Subscriber Badge on Wednesday December 19 2018, @07:46PM (#776472) Journal

        I'd like to compare the numbers if possible.

        Those numbers are so complex you can't compare them.

        --
        https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
        • (Score: 1) by nitehawk214 on Wednesday December 19 2018, @08:05PM (2 children)

          by nitehawk214 (1304) on Wednesday December 19 2018, @08:05PM (#776483)

          If you factor out the i you can compare them.

          --
          "Don't you ever miss the days when you used to be nostalgic?" -Loiosh
          • (Score: 2) by c0lo on Wednesday December 19 2018, @08:10PM (1 child)

            by c0lo (156) Subscriber Badge on Wednesday December 19 2018, @08:10PM (#776489) Journal

            Can't factor out the i for too complex numbers.

            --
            https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
            • (Score: 0) by Anonymous Coward on Wednesday December 19 2018, @09:41PM

              by Anonymous Coward on Wednesday December 19 2018, @09:41PM (#776550)

              Still, you should be able to compare the magnitude of the numbers even if they are complex.

              Then again, is that the right comparison? Because I would obviously prefer to spend -$100 than $10, even though the latter has a smaller magnitude...

              *throws arms up* Argg!

    • (Score: 0) by Anonymous Coward on Wednesday December 19 2018, @04:13PM

      by Anonymous Coward on Wednesday December 19 2018, @04:13PM (#776361)

      It'd be well within the Heavy's capabilities, and recovering the three boosters probably means that it would be cheaper as well.

      Recovering the first stages is cool. However it remains to be seen whether recovering boosters is actually cheaper in the long run. Regardless of the economics of recovering one falcon 9, it seems exceedingly unlikely that launching 3 rockets with the intent of recovering them would be cheaper than launching one with the intent of not recovering it.

      Remember that booster recovery means you need more mass (landing struts and whatnot), and also more fuel, which also means more mass, and the rocket equation gets you every time.

    • (Score: 0) by Anonymous Coward on Wednesday December 19 2018, @09:24PM (1 child)

      by Anonymous Coward on Wednesday December 19 2018, @09:24PM (#776539)

      After the Heavy launched, I distinctly remember Elon saying that it meant the end of expendable Falcon 9, that any payload too heavy for a return would use a Heavy instead as it would be better all around.

      I assume that doesn't apply if they have a 9 that needs to be retired anyway. Or maybe SpaceX doesn't think they have fixed the problem with the center core yet (though I don't know why it would take so long since the problem was supposedly just running out of lighter fluid). Or maybe there is a problem building the Heavy that makes it significantly more expensive than expected.

      I guess it's possible that the Air Force could have insisted, but I don't know why they would since the Heavy is tested and qualified for commercial satellite launch, and it's not like a GPS satellite is irreplaceable if the launch did fail. It seems like the perfect use for it assuming they have one available.

      • (Score: 0) by Anonymous Coward on Thursday December 20 2018, @03:18AM

        by Anonymous Coward on Thursday December 20 2018, @03:18AM (#776649)

        "I guess it's possible that the Air Force could have insisted"

        I kind of wonder about that. Like maybe the spec isn't about performance so much as it is about making the spec to fit a particular vendor. Because of course that vendor always shows up with free booze and hookers. Must be nice being an airforce general. Never get shot at. Get free jet flights anywhere you want to go, and best of all never have to pay for all the perks that comes along with billion dollar manufacturing contracts.

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