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SpaceX Successfully Lands Its Rocket On A Floating Drone Ship For The First Time (theverge.com) 206

An anonymous reader quotes a report from The Verge: SpaceX has finally landed its Falcon 9 rocket on a drone ship at sea, after launching the vehicle into space this afternoon. It's the first time the company has been able to pull off an ocean landing, after four previous attempts ended in failure. This is the second time SpaceX has successfully landed one of its rockets post-launch; the first time was in December, when the company's Falcon 9 rocket touched down at a ground-based landing site in Cape Canaveral, Florida, after putting a satellite into space. Now that SpaceX has demonstrated it can do both types of landings, the company can potentially recover and reuse even more rockets in the future. And that could mean much greater cost savings for SpaceX.
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SpaceX Successfully Lands Its Rocket On A Floating Drone Ship For The First Time

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  • Dear lazy web, any higher quality video out there?
    Congrats SpaceX, this looks really impressive.

  • It didn't even mention that SpaceX was launching today.

  • Now we just order the drone ship back to port! ...

    Uhh... that wasn't a story in the epic

    • by Ksevio ( 865461 )
      Actually the weld the rocket to the barge and tow it back over a few days. The drone ship can really only stay in one spot autonomously.
  • by drew_kime ( 303965 ) on Friday April 08, 2016 @05:46PM (#51871143) Journal

    Anyone know why they would come in at an angle and straighten up at the last moment? Is it actually easier to control that way, or is it to protect the landing pad in case of a list-second abort?

    • by fgodfrey ( 116175 ) <fgodfrey@bigw.org> on Friday April 08, 2016 @05:55PM (#51871207) Homepage

      There are two reasons that I've seen.

      Because the rocket is almost out of fuel, even burning only one engine at minimum throttle, the thrust to weight ratio is more than one (ie, the rocket would fly, not land). So, they can't hover, they have to hit the ship and shut the engine off at the exact moment that the velocity is zero (or very close to it). So, to help with that problem, they come in at an angle which helps consume at least some of the thrust in a direction that isn't upward.

      The second reason is, as you say, to protect the landing platform. If they run out of fuel (or the engine fails or....), the stage just drops into the ocean rather than crashing into the barge at a very high speed. That said, based on their last several failed landing attempts, that barge can take quite a hit and stay in one piece....

      • by wildsurf ( 535389 ) on Friday April 08, 2016 @07:22PM (#51871749) Homepage

        There are two reasons that I've seen.

        Third reason: Wind. In the post-launch press conference, Elon mentioned that the wind was significant during landing. (And may reach up to 50mph tomorrow on the way back to port.) So the rocket had to tilt somewhat into the wind to avoid being blown sideways relative to the landing pad, and only went vertical at the last moment. It also explains why the droneship maintains a slight tilt in some of the post-landing footage; this is to cancel out the considerable force of the prevailing wind.

    • by Sowelu ( 713889 )

      As a universal rule, on your way back down to a planet, you want to to apply maximum force for a short of a time as possible and at the last second possible. Anything you do to slow your descent before that means that you're fighting gravity for a longer time, and that wastes fuel. They don't have the resources to change their approach angle--and even if they did, shallow means it's hitting more air resistance on the way down, which means you slow down for free.

    • Anyone know why they would come in at an angle and straighten up at the last moment?

      Because they have to control vertical *and* horizontal velocity. Simple as that.

  • Obviously now we have to see the recovery percentage that SpaceX can achieve, especially when they start landing Falcon Heavy on three barges, the one for the center booster being much farther downrange than the others. Seeing three land, two of them simultaneously, is going to be pretty amazing. If they can recover a lot of them, this completely changes the economics of space flight beyond the 30% discount SpaceX is quoting in the short term.

    And don't forget that they are getting the Dragon back too, and Dragon 2 with its eventual ground-landing capability is expected to be reusable. Currently Dragon 1 lands in sea water, and the reuse they have so far is only of the pressure vessel, the capsule is stripped down to that and rebuilt.

    Recovering the second stage is possible although not currently on the SpaceX roadmap. They would need to fly it with a heat shield.

    Now, consider what it would take to land a Dragon on the moon and return. Not inconceivable, given Falcon Heavy and a few launches.

    • From what I've read, the side booster stages of Falcon Heavy will always be able to make ground landings; they don't go nearly as far or fast as the central stage. I'm sure it still costs some payload to go for the ground landing with the side boosters, but not nearly so much. The central stage, though... that burns for a considerable while after the side boosters detach (it spends much of the flight at low throttle, plus there's the whole propellant crossfeed thing, assuming they ever get that working), an

      • SpaceX has stated that about 30% of rockets launched overall will be able to RTLS. That's why the barge is so critical. F9 Heavy will only be able to RTLS depending on the total delta-V demanded for the mission. There is a delta-V cost for RTLS, you can't just do it on the grid fins.

  • Being able to inspect intact engines after a real mission would improve its development and refinement.
    • Exactly - not throwing everything away has advantages. SpaceX deserves to be congratulated for pulling this off. There's lots to be said for incremental improvement.

  • That's the analogy to think about with this. When is it best to use the artillery approach, and when is it best to use an airplane approach. An airplane approach implies refueling and re-use. You can amortize investments to improve capabilities over time. Artillery is all about cheap getting payload up there.

    If you really want to get pure mass to LEO cheaply - it's hard to beat big artillery with a rocket stage. It has a few issues though.
    Your payload has to be able to handle the G's from firing. The

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