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Space Technology

SpaceX Launch Postponed 77

Posted by samzenpus from the second-time's-a-charm dept.
An anonymous reader writes with news about SpaceX's launch today and second attempt to land its Falcon 9 rocket on a platform floating offshore in the Atlantic ocean. "You can watch live as SpaceX launches its Falcon 9 rocket and attempts to recover the first stage portion via an automated, barge-based landing plan in the Atlantic ocean, with the first take-off attempted scheduled for 4:33 PM ET, provided conditions remain good and pre-flight checks go well. A big part of this mission, designated CRS-6 and designed primarily as a resupply flight for the International Space Station, is getting a second chance at recovering Falcon 9's first stage rocket. Once the second stage and the Dragon spacecraft detach from that first stage rocket, it'll undergo a controlled descent as it attempts to touch down with SpaceX's ocean-borne landing platform." Update: 04/13 21:43 GMT by S : The launch was scrubbed because of lightning in a nearby cloud. It's been rescheduled for tomorrow at 4:10PM ET.
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SpaceX Launch Postponed More

SpaceX Launch Postponed

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  • I thought I heard the commentator mention a one second launch window. Did I hear that right?

    • Re: (Score:2)

      by zwede ( 1478355 )
      Yes, that is correct.

    • Re: (Score:2)

      by bledri ( 1283728 )

      I thought I heard the commentator mention a one second launch window. Did I hear that right?

      Yes, that's correct. Technically I think it's actually a one minute launch window, but there is not really any scenario where that matters. This is because if there is a launch hold the clock cycles back to T-13 minutes. There is no practical way to have a hold at T-13 or less, resolve the problem, and then target a new launch time within that one minute window. So the launch targets the specific second which optimizes rendezvous with the ISS.

      They also call this an instantaneous launch window.

    • Re: (Score:2)

      by 0123456 ( 636235 )

      The shuttle also used to have really short launch windows to ISS (~5 minutes?). That just meant they started the countdown early and added longer holds to allow time to fix any problems that showed up; if the problem took longer than the allowed hold time, it was complex enough that they would probably have to scrub anyway.

      • +/- 5 minutes was the shuttle's window and it cost 1100kg of payload to have a window that large (reference link [baen.com]).

        The dog-leg cost of slipping into the proper inclination orbit with a launch that is mistimed can huge. On the order of hundreds of dV required to fix the issue.

        So for robotic launches, where you don't have crew sitting in a capsule / vessel, and scrubs are relatively cheap as a result, it's better to go for a very small launch window (~1 second) to maximize payload.

  • Getting just a few seconds of video and then having to hit reload, over and over, isn't exactly my idea of live.

  • Aborted due to weather at T- 3:07
  • Damn! Got my hopes up.
  • They aborted because of an "Anvil Cloud".

  • Cancelled due to weather (anvil clouds) at T-00:03:07.

  • Weather is bad, launch has been aborted. Tomorrow is the next chance (IIRC).

  • Headline got ahead of itself (Score:5, Informative)

    by wonkey_monkey ( 2592601 ) on Monday April 13, 2015 @03:33PM (#49465601) Homepage

    SpaceX Launches CRS-6 Resupply Rocket and Tries Drone Ship Recovery

    That'll teach you to use the present tense for something that hasn't happened yet.

  • Aborted at T-00:03:07 (Score:5, Informative)

    by compro01 ( 777531 ) on Monday April 13, 2015 @03:33PM (#49465605)

    Weather doesn't want to cooperate. Anvil clouds within 10 miles of launch site.

    Tune in tomorrow for next attempt.

    • Weather doesn't want to cooperate. Anvil clouds within 10 miles of launch site.

      Tune in tomorrow for next attempt.

      Next lift-off attempt is tomorrow at around 4:10 PM EDT, if I heard correctly.

      • Re: (Score:2)

        by Sowelu ( 713889 )

        Today's attempt, they expected a 60% chance of clear enough weather. Tomorrow they expect 50% chance, so...fingers crossed?

    • Weather doesn't want to cooperate.

      Don't try to anthropomorphize the weather. It hates that.

  • Launch has been scrubbed (Score:4, Interesting)

    by ZeroSerenity ( 923363 ) <gormac05@ y a h o o . com> on Monday April 13, 2015 @03:36PM (#49465629) Homepage Journal
    Way to jump the gun there.

  • Why a one-second launch window? (Score:4, Insightful)

    by gman003 ( 1693318 ) on Monday April 13, 2015 @03:39PM (#49465651)

    I've seen short launch windows before, but not for ISS-bound launches. I remember previous Dragon launches having significantly longer windows to launch. Am I remembering wrong, or is there something about this launch that requires a shorter window?

    • You're remembering wrong. Most ISS launches have windows a few seconds wide, at most. There's a lot of stuff in LEO, all moving very fast, If you want a course that will hit the ISS at exactly the right speed, and not come too close to anything else, you've got a narrow window to do it in. You *can* launch outside that window (space is a big place), but it eats into your fuel and safety margins and usually there's no reason to do that.

      • That makes sense, and I recall that this is the most heavily-loaded Dragon yet, so less dV for orbital maneuvers would make for a shorter launch window.

        And I did seem to be remembering things wrong - every previous CRS flight I could find a launch window for had an instantaneous launch window. I must have been thinking of the non-CRS flights.

      • Re:Why a one-second launch window? (Score:4, Interesting)

        by DerekLyons ( 302214 ) <fairwater@gmai l . c om> on Monday April 13, 2015 @06:46PM (#49466671) Homepage

        You're remembering wrong. Most ISS launches have windows a few seconds wide, at most. There's a lot of stuff in LEO, all moving very fast, If you want a course that will hit the ISS at exactly the right speed, and not come too close to anything else, you've got a narrow window to do it in.

        You're explaining wrong. It has nothing to do with "other stuff" in LEO, and everything to do with the ISS's high inclination orbit. The plane of the orbit only passes over Cape Canaveral at intervals, and if you miss that window it will take excessive energy to match planes with the ISS.
         

        You *can* launch outside that window (space is a big place), but it eats into your fuel and safety margins and usually there's no reason to do that.

        Um, no. The width of the window is determined by the performance (available energy) of the booster and payload - you can't launch outside of it at all and reach the target. That's why windows exist in the first place.

        • Nothing to do with other items in orbit, I can believe. The ability to launch a little outside the window and still make it, though, should be valid unless they are running on a lot less margin than I expect. I know the first stage, at least, has *some* margin, or it wouldn't be able to do the deceleration and landing burns.

          • Yes there is margin.

            But not launching on the exact instant when the ISS inclination is properly aligned with the launch site is expensive. The shuttle launches had to sacrifice 1100kg of payload [baen.com] in order to have a 10 minute wide launch window.

            For a robotic launch where you can easily safe the vehicle after a scrub and don't have to unload passengers from the capsule, delaying 23h37m is not a huge deal. So you go with a much shorter launch window and gain a lot more payload to orbit. And if things don

          • Matching the orbital planes (due to a mismatch caused by launching outside the window) is performed by the payload once in orbit - not by the first stage during boost. That's the margin problem - the payload hasn't enough delta-V.

    • Re: (Score:2)

      by idji ( 984038 )
      the get to ISS in hours with this window, rather than days with the window you remember.
  • SpaceX had to scrub its launch today. The launch was 'racing' to beat a weather system moving through the area ('attached anvil cloud') and had to scrub the launch with just 3min to launch. There will be another try, tomorrow. http://www.spacex.com/ [spacex.com]

  • Attached-anvil clouds (Score:4, Informative)

    by ClickOnThis ( 137803 ) on Monday April 13, 2015 @03:45PM (#49465711) Journal

    The launch was scrubbed due to attached-anvil clouds and lightning risk.

    For the curious, attached-anvil clouds are also known as cumulonimbus clouds. [wikipedia.org]

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