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SpaceX's Latest Launch Successful, But Ends With a "Hard Landing" (theverge.com)

Posted by ryuzaki0 on from the that's-some-soft-pedalling dept.

Eloking writes with this news from The Verge: SpaceX successfully launched its Falcon 9 rocket into space this afternoon, but — as expected — failed to land the vehicle on a drone ship at sea afterward. CEO Elon Musk said the rocket 'landed hard' on the drone ship. The mission requirements made a successful landing unlikely. This was SpaceX's fourth attempt to land the Falcon 9 post-launch on an autonomous drone ship floating in the ocean. All of the previous sea landings failed too, though the third attempt came very close. The company had low hopes of a successful landing from the start of this mission, since the rocket had to send a heavy satellite into a high orbit. That requires a lot of fuel for the launch itself, so there wasn't much fuel left for the rocket's return to Earth and powered landing.

9 of 129 comments (clear)

  1. Expectations game by ratnerstar · · Score: 4, Funny

    SpaceX and Marco Rubio are duking it out to see who wins "best management of the expectations game." Personally, I'm gonna give "third place win" the edge over "successful failure," but that's just me. Good hustle all around guys!

    --
    Just because you sold your soul to the devil that needn't make you a teetotaler. --The Devil and Daniel Webster
    1. Re: Expectations game by beelsebob · · Score: 4, Insightful

      Right, successfully inserting a communications satellite into geostationary orbit, exactly as contracted to do... Such a fuck up.

    2. Re: Expectations game by Applehu+Akbar · · Score: 5, Interesting

      "When NASA has a launch failure or even a postponement it's nightly news, complete with commentary as to how it's all a waste of money, government can't do things right, etc."

      The public expects a government space program to be run with perfect safety, which everyone in the business knows is as unattainable as safe aviation was in 1920, and that it must not do anything "adventurous" like landing a booster, even if the activity is not mission-critical and does not pose any threat to human life. Manned space programs have to go private not because NASA is incompetent, but because only the private sector is allowed to take risks.

    3. Re:Expectations game by Teancum · · Score: 3, Interesting

      I don't think it was "almost." That describes the landing when the first stage touched down then tipped over.

      There wasn't really much of an expectation it would be successful anyway. The largest problem was that there was very little reserve fuel left in the rocket due to the fact that nearly all of the fuel needed to get the payload delivered to GEO (also due to the heavier payload itself) that it wasn't really thought that the rocket could land.

      SpaceX basically made an attempt anyway. Close in this case is that the rocket ran out of fuel when it was close (in proportion) to hovering velocity, but 1%-2% of the original velocity when it was in space was still going way too fast to land gently.

    4. Re:Expectations game by Rei · · Score: 4, Insightful

      Are there still people here who don't know the difference between an orbital and a suborbital rocket? I thought we were past that.

      AmiMoJo: the difference between landing a suborbital rocket and landing an orbital rocket is the difference between jumping off your couch and landing on your feet without falling over, and jumping off a ladder and landing on a pogo stick without falling over.

      --
      Stale pastry is hollow succor to one who is bereft of ostrich.
    5. Re: Expectations game by Teancum · · Score: 4, Insightful

      Well, I think part of his argument is that they aren't doing it. How many successful landings have they had on their barge?

      How many successful landings has anybody had from landing a 5 story tall launch vehicle above the Karman Line (aka what is commonly thought of as actually outer space) and then landing that rocket on a barge in the ocean?

      I think the level of expectation here is just a tad bit high, where even the notion of calling this a failure is simply absurd.

      Very useful engineering data was obtained on this flight, including in the landing. For a rocket that wasn't expected to be recovered at all in this particular case, SpaceX did a pretty good job at trying to recover it, and got some pieces anyway as it actually did land on the barge.... just not as slowly as necessary to get it in one piece.

  2. Re:Why not have a big net by JoshuaZ · · Score: 3, Informative

    The rocket is not designed to handle stress from all angles. Flopping into a net would entail coming down hard in a direction that it is not designed to handle stress. The primary advantage of a vertical landing is that most of the stress remains vertical just like when the rocket is being launched. Building it to handle other directions would require much more mass. They'll get this to work eventually, and this was a very difficult run anyways because the orbital profile required the rocket coming down from higher up, at a higher velocity and with less fuel to work with. Please be patient.

  3. Re:Why the drone ship by Guspaz · · Score: 3, Informative

    It's all about the fuel. On launches that leave enough spare fuel, they actually return the rocket all the way back to a landing pad at the launch site in Florida. They successfully landed the rocket once in that manner. But on launches that require more fuel (to put a heavier payload into a faster orbit), there isn't enough fuel leftover for the burn that would send the rocket back towards the launch site. As a result, they are limited to a relatively ballistic trajectory from the launch site, which means landing somewhere out to sea. The landing destination is actually pretty precise (the drone ship is trying its best to stay stationary, not move to meet the rocket), it's just that it's the only place they have enough fuel to get to.

    The first stage of the rocket never reaches orbit: it's still going really really fast, but not orbital velocity. So after the second stage separates, left alone, the first stage would start falling down again downrange and crash into the ocean.

    Normally, after separation, the first stage flips itself over and then does a boostback burn to kill the forward momentum, and give it enough momentium backwards to line up its trajectory back towards the launch site. Then later it does a deceleration burn to slow itself down to keep the atmosphere from ripping it apart. And then finally, it does a landing burn for the last segment to slow it to a stop.

    On some missions, they don't have the fuel to do that full boostback burn, so they kill some of the forward momentum, but that's it.

  4. Re:ocean landing will not happen during rough seas by Bruce+Perens · · Score: 3, Informative

    The challenge here for SpaceX is that a single engine can not throttle down enough to hover the empty booster. That's why they call it "hoverslam", if the engine stayed on the rocket would bounce back up. There would be a lot more room for error correction if that was the case.

    --
    Bruce Perens.