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SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

Posted by Soulskill on from the good-luck dept.

An anonymous reader writes: SpaceX has announced that at the conclusion of its next rocket flight, it will attempt a precision landing of its Falcon 9 first stage onto an autonomous ocean platform. They say the odds of success aren't great, but it's the beginning of their work to make this a reality. Quoting: "At 14 stories tall and traveling upwards of 1300 m/s (nearly 1 mi/s), stabilizing the Falcon 9 first stage for reentry is like trying to balance a rubber broomstick on your hand in the middle of a wind storm. To help stabilize the stage and to reduce its speed, SpaceX relights the engines for a series of three burns.

The first burn—the boostback burn—adjusts the impact point of the vehicle and is followed by the supersonic retro propulsion burn that, along with the drag of the atmosphere, slows the vehicle's speed from 1300 m/s to about 250 m/s. The final burn is the landing burn, during which the legs deploy and the vehicle's speed is further reduced to around 2 m/s. ... To complicate matters further, the landing site is limited in size and not entirely stationary. The autonomous spaceport drone ship is 300 by 100 feet, with wings that extend its width to 170 feet. While that may sound huge at first, to a Falcon 9 first stage coming from space, it seems very small. The legspan of the Falcon 9 first stage is about 70 feet and while the ship is equipped with powerful thrusters to help it stay in place, it is not actually anchored, so finding the bullseye becomes particularly tricky."

16 of 81 comments (clear)

  1. Hmm by Rei · · Score: 4, Interesting

    Why don't more billionaires do stuff like this?

    I'm not saying do it "for the benefit of humanity", or even "for a profit". Just simply.... if you have billions of dollars, and you want to spend it on something, what can you possibly spend it on that wins in a sheer awesomeness category as "shooting a gigantic rocket up into orbit and then landing it on a robot boat in the middle of the ocean"? That's like a freaking video game, played with 1500 tonnes of aluminum and highly combustible fuel.

    --
    "We consider that six courts and an asylum claim are a rather odd way of returning to Sweden within a month."
    1. Re: Hmm by theCzechGuy · · Score: 4, Insightful

      Really? So how many space contractors can deliver payload to ISS at this moment? SpaceX isn't doing anything better than all those that can't? And how many contractors can deliver a kilogram of payload to the orbit for a comparable price to SpaceX? I get that some people may be sick all the adoration SpaceX is getting lately, but that's not a good excuse for ignoring the reality and substituting your own.

    2. Re:Hmm by pavon · · Score: 2

      Running a business like this takes a lot of work, and for it to succeed well enough to actually get working rockets off the ground you need to attract top-notch engineers who believe that working for you isn't just a waste of their time (more than a billionaire's plaything), and management that can create the right environment for them to succeed without blowing through your money for nothing. It is much less expensive, less risky and less time consuming to just pay Russia for a thrill ride than to create your own rocket company. So I can understand why most would choose to go that route, and leave the latter for those who genuinely want to shake up the market.

    3. Re:Hmm by Teancum · · Score: 2

      In fairness to Elon Musk, he actually wanted to blow about a half billion dollars on sending a greenhouse to the surface of Mars.... pretty much as a philanthropic venture or as just blowing the money for the hell of it. He even got so far as going to Russia and trying to negotiate the purchase of an ICBM to get the project to happen (where they even offered the nuclear warhead with the deal... something he turned down).

      Along the way, one of those in Russia insulted him big time and basically challenged him to try and do this himself. After a little investigating about the topic, he went to Los Angeles County to recruit a few aerospace engineers who were building rockets capable of going into orbit as a hobby, and offered them a full time job to make a clean-sheet new rocket from scratch. That company is now SpaceX. The hobby guys are still making rockets that are being launched in the Mojave desert, but a great many of those guys are getting hired by a new set of space-related companies building stuff now.

  2. I would love to watch this by jfdavis668 · · Score: 2

    from a safe distance.

  3. As long as they get close it's a win by trout007 · · Score: 4, Informative

    The goal isn't to land on a barge, but back at the launch site (or at least near it). If they can show over a couple attempts that they get close to the target then they can move to doing this over land. They have already proven they can do this in Texas many times. It doesn't really matter if they tip over over land too hard at sea. What you don't want is that it missed by a mile or cartwheels out of control.

    --
    I love Jesus, except for his foreign policy.
    1. Re:As long as they get close it's a win by DerekLyons · · Score: 2

      If they can show over a couple attempts that they get close to the target then they can move to doing this over land. They have already proven they can do this in Texas many times.

      There's a reason why they're flying all these attempts over water - they haven't done it in Texas even so much as once. The flights in Texas have been "take off, go a short distance up, then land more-or-less right back where you started" - which isn't the difficult part (so far as flight control is concerned, it's more of an engine control problem) as small errors have no time to propagate. The difficult part (from the flight control POV and the reason they are testing on a barge) is the boostback and retro burns, where even small errors in attitude and delta V propagate into significant errors by the time you hit your hovering gates (and is thus an engine control *and* a flight control problem). Another issue, also not tested in Texas, is the aerodynamics and flight dynamics of the returning stage (especially in the high speed regime), and indeed these issues caused a problem on the first attempt.

      So no, coming close isn't a win. They're going to have to demonstrate pinpoint recovery a number of times before anyone is going to let them even consider attempting it over land.

    2. Re:As long as they get close it's a win by Teancum · · Score: 2

      I don't think the issue is attempting a landing on land, but rather that the proposed site for landing (I think they are proposing to use the site originally designed to become 39C before NASA scrapped that location for Apollo Saturn V launches) is so close to other critical infrastructure.

      If they landed on some use spot of semi-wilderness like where Russia does landings for the Soyuz spacecraft, the Australian outback, or some other similar sized far from civilization, they wouldn't have any problem with attempting a landing on land. The problem is that the eastern coast of Florida is hardly what I would describe as unpopulated wilderness. The chance of the Falcon 9 landing in Miami or even Disney World is just too great. That is why the pinpoint accuracy is so needed, especially with the suicide burn approach that SpaceX is using for the core recovery.

  4. fuel weight by trybywrench · · Score: 3, Insightful

    I thought the main limiting factor of lifting mass to space was also having to carry the fuel with you? SpaceX hauls its fuel to get to space and even extra fuel to land. How are they able to afford to lift the extra mass? Are their engines that much more efficient? I'll stop with the questions marks ;)

    --
    I came to the datacenter drunk with a fake ID, don't you want to be just like me?
    1. Re:fuel weight by DMUTPeregrine · · Score: 2

      They're only lifting extra mass on the first stage, not the payload. So it doesn't have to move the extra mass as much.

      --
      Not a sentence!
    2. Re:fuel weight by drayath · · Score: 5, Informative

      First issue is economics, fuel cost is 1-3% of launch cost. If you can only get half the payload weight to orbit but get most of your rocket back for reuse (and the first stage is the most expensive bit - 9? engines vs one for second stage), cost per Kg to orbit is still (massivly) cheaper.

      Second issue is that the fuel cost for the first stage recovery is quite cheap, you only have to brake and land the engine and (almost) empty fuel tank so they are very light vs the lauch mass. From memory a while ago spaceX started using v2 of there main engine which was ~10% more efficent than the v1 engine; This gave enough increased performance that even with extra fuel to land and the extra weight from the landing legs etc. they could get the same payload to orbit plus do styage one recovery.

    3. Re:fuel weight by gman003 · · Score: 2

      Rockets themselves are expensive. Rocket fuel, particularly the sort SpaceX uses, is dirt cheap in comparison - only $200K of their $56M launch cost.

      Yes, having that extra fuel decreases their payload capacity (from what it could be). But they don't need as much fuel when descending, since they no longer have a second stage and payload weighing them down, so it isn't much fuel in total.

      However, the cost of not having to rebuild the rocket every time is much more significant. Even if they can only reuse it a few times, that's a lot of production cost being saved.

    4. Re:fuel weight by rufty_tufty · · Score: 2

      There is no extra fuel as such.
      All rockets have more fuel in them than needed for their base mission to account for failure modes. For example if the engines produce less thrust than planned for, it means they can simply burn for longer to still deliver the payload. The Falcon re-usable rockets will use this extra fuel for the flyback if things don't go wrong.
      In the event of an engine out on a Falcon 9 it is highly likely that this margin fuel will be used and therefore that Falcon will not be re-usable because it won't be able to fly back.
      So yes there's extra fuel, but it's extra fuel that sometimes will be needed for the main mission.

      --
      "The weirdest thing about a mind, is that every answer that you find, is the basis of a brand new cliche" -
  5. Re:Why not on land? by captainpanic · · Score: 2

    Probably safety... They expect it to go wrong. Even the most remote places on land have some people. And with this highly experimental flight, the exclusion zone around the expected landing site must be huge. That's only possible at sea.

  6. Re:splashdown by Anonymous Coward · · Score: 2, Informative

    They tried, but even at slow speeds, the rocket will eventually land, and then belly-flop on the water surface, with causes too much damage, or at least make the structure too unpredictable to re-use. The space-shuttle boosters where also recovered in this way, and for the same reason never re-used.
    The added weight for making it strong enough to handle a belly-flop into the waves is much larger than anything needed to deal with landing on a barge, even so larger that the payload would be reduced to 0.

  7. Re:Someone doesn't understand basic relativity by jabuzz · · Score: 2

    Yes the tower backs away and the holding clamps release. However this happens literally as the rocket blasts away. Have you never watched a a video of a Saturn V launch? Try this one a high speed 500fps 16mm footage from the base of the Apollo 11 rocket. Notice how the holding clamps release to let the rocket move away, which they only do when they get the signal from the onboard systems that all five F1 engines are working properly.

    https://www.youtube.com/watch?...