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Space

SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship 81

Posted by Soulskill 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."
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SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship More

SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

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  • Hmm (Score:5, Interesting)

    by Rei ( 128717 ) on Wednesday December 17, 2014 @09:20AM (#48616227) Homepage

    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.

    • Because they became billionaires through luck ambition and pinching penny's. Not by doing cool things.

      Also it is relative to the interests of the billionaire themselves. While most don't like Larry Ellison for oracle. Those billions are being spent on make awesome sailboats and doing major races with them for personal glory. Of course he is doing it the Larry Ellison way so some don't like him for it but the advances made in hull design over the last decade have been impressive.

    • The wealthy have ALWAYS done stuff like this, which is how they became outrageously wealthy. That's how we got railroads, power grids, and aviation.

      • But railroads, power grids, aviation, oil infrastructure that supports global trade and 2-day deliveries of almost anything you could want, software and hardware that revolutionized society with personal computing... All these are boring commonplace things. Billionaires are just penny-pinchers that are screwing us out of our money for nothing in return.

      • those were all govt funded and developed, then leeched off of by the wealthy.

        • Railroads - partly. Power grid - yes, at least in most of Europe. Aviation - not really. It all started with private entrepreneurs, the first time governments started any interest in aviation, it was WW 1.

          • You raise an interesting point: if you want the government to take an interest in your idea, think of way of weaponizing it. Apollo was sold as an escalation of Cold War rivalry.

            • True, but you also have to have a conflict that allows the government to justify the spending. It doesn't always have to be an open one (as was the case with Apollo and the Cold War), but it still seem as inefficient way to make any progress.

  • I would love to watch this (Score:3)

    by jfdavis668 ( 1414919 ) on Wednesday December 17, 2014 @09:28AM (#48616283)
    from a safe distance.

  • As long as they get close it's a win (Score:5, Informative)

    by trout007 ( 975317 ) on Wednesday December 17, 2014 @09:34AM (#48616305)

    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.

    • Re: (Score:1)

      by Anonymous Coward

      No... the goal is to land on the barge. Otherwise there would be no barge, just an arbitrary lat long that they aim for,

    • Re: (Score:1)

      by KIngo ( 168933 )

      The center core of a falcon heavy (the triple-core version) stages too far away in order to return to the launch site. It will be landing on that barge.

      • You mean it drops off too high and downrange to boost back to the launch point and too low to achieve most of one orbit before boosting back to the launch point. Right?

    • 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 eng

      • You missed quoting the important part.

        It doesn't really matter if they tip over over land too hard at sea.

        As long as they show a good landing burn over the landing zone it doesn't matter if a pitching deck causes a landing failure.

        • No, I missed the quoting the part that was (more-or-less, mostly less) correct. The parts I quoted were parts that you were wildly incorrect on, as there's considerable distance between what has been tested, and what they are testing. Even so, you're still wrong. Miss the target, by even a little bit, and it's a loss. Land hard and lose the vehicle (not due to sea state) and it's a loss. Tip over and lose the vehicle and damage or lose the barge (not due to sea state), and it's a loss.

          So yes, it does m

          • Re: (Score:2)

            by matfud ( 464184 )

            A very negative point of view.

            The stage is a loss anyway if they did not try to get it back down and land it. If not it would eventually renter and burn. I thought that was the whole point. Trying to get it back in one piece where you want it to land. If you get it back in one or a few bits then it is a win over just just chucking it up there and knowing you have lost it (as most rockets do)
            There is cost in trying to do so. And yes they do need a perfect pinpoint landing to achieve it. Missing by a bit woul

            • A very negative point of view.

              Only in the eyes of the completely clueless or the drooling fanboy (not there's much effective difference between the two) are facts "negative".

              If you get it back in one or a few bits then it is a win over just just chucking it up there and knowing you have lost it (as most rockets do)

              Since the goal is to recover it whole, no, getting back in 'a few bits' is not a win. It's a failure. That things can and will be learned from such a failure does not change this.

              • Re: (Score:2)

                by matfud ( 464184 )

                Facts are facts. If you decide that they are bad then you will not have much fun in life, perhaps you should look at the upside and what you learned from those facts. Even if the rocket breaks up and plummets into the ocean there is information there that may be useful for your perfect landing criteria.

                Only one of the goals is to land perfectly. Gosh who would have thought that there may be more than one goal.

          • I'll try one more time. They have shown they can land from a stable position in Texas. If they can show they can get from second stage separation to a similar configuration over a barge in the ocean then it's a success. If they can it will show they have good enough control that range safety will allow them to fly back to try to land on land.

      • Re: (Score:3)

        by Teancum ( 67324 )

        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 a

    • White Sands Missile Range is right next to the Spaceport America and has 4,000 square miles of uninhabited desert. The Army tests rockets there all the time, and sometimes closes highway 70 (which passes through the range) when they do. Since the goal of cheaper launch costs is something the miltary would find useful, I am pretty sure Spacex could come to an agreement to do some testing using the range. Before talking to the Army, Spacex would probably want to run several real tests at sea, where they wou

  • fuel weight (Score:4, Insightful)

    by trybywrench ( 584843 ) on Wednesday December 17, 2014 @09:43AM (#48616357)
    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 ;)
    • 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.

    • Re: (Score:1)

      by Anonymous Coward

      The Falcon 9 1.1 version is much heavier than the v1 ( and the engines better ), so it can carry over 50% more payload to space. Since that payload is not actually needed for its planned mission, they can afford to carry more fuel in the first stage to attempt recovery.

    • I surely hope that they will let the atmospheric drag slow them down a lot too, like other space vehicles.

      While they do have to carry all that extra fuel, they don't have to rebuild the rocket. They only refuel it. The savings are enormous.

    • Re:fuel weight (Score:5, Informative)

      by drayath ( 158040 ) on Wednesday December 17, 2014 @09:57AM (#48616459) Homepage

      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.

    • Re: (Score:2)

      by gonar ( 78767 )

      in theory, if you can land the rocket back on dry land, you can refurbish it and reuse it for enough less than the cost of the extra fuel/landing gear/etc to make it a net cost reduction over several launches.

      yes, you are losing some mass fraction of orbital payload, but if the cost savings are sufficient to justify the extra initial expense, then it is a win.

    • Re: (Score:1)

      by Anonymous Coward

      Everything is a tradeoff. Some fuel saved for landing first stage means there is less payload capability. But they definitely can afford it.

      Right now they have a rocket (Falcon 9 v1.1) that can put bit over 13 tons to low earth orbit *while* softly landing the first stage (reserving some of the fuel for it, adding weight of the grid fins that steer the stage and landing legs).

      Exact same rocket, no legs, no grid fins, no fuel margins could put a couple of tons more to LEO (as to how much is not clear as Spac

      • Re: (Score:2)

        by matfud ( 464184 )

        Many liquid fuelled rockets never run until they run out of fuel. They are shut off at the appropriate time/place/velocity. So there tends to be fuel "left over" anyway. Now the total mass of one of these 1st stage rockets is primarily fuel/oxidiser. They do not mass much without anything in them. So trying to land it is not quite as expensive as you may think if you take into account the left overs. I presume they are going with the "If there is not enough fuel left let it burn" approach. Sort of trimming

    • Re: (Score:2)

      by idji ( 984038 )
      As Elon Musk says MANY times fuel is only 10% or less of the cost of a launch, and as he says MANY times no-one would throw away a Boeing 747 after each flight as it is too expensive.
      He takes extra fuel for the landing - this means he can only launch a lighter cargo, but he can one day reuse his rocket again, so it is worth it.
      The last Falcon 9 flight http://en.wikipedia.org/wiki/S... [wikipedia.org] did not attempt a landing because it took a cargo of 2,216 kilograms (4,885 lb). The last flight which attempted a landing

      • The Falcon 9 weighs about 500000kg on launch.
        Most of this is kerosene, and liquid oxygen.
        Both of these can be purchased for under $1/l.
        This is around $400000 or so.
        A falcon 9 launch costs $60M or so - so it's more like a percent.

    • 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

      • 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.

        The money saved by not having to produce a new vehicle is offset by the money spent on fixed infrastructure and on recovering and refurbishing the vehicle for the next flight. Airline travel is as a cheap as it is because they've gotten between-flights maintenance down to essentially zero (basically only emergent work) - the expe

    • Their lifting capacity, even with the extra fuel (really, reduced fuel available for ascent) is sufficient, and the small amount of payload reduction is vastly offset by the cost savings of re-using 9 engines plus structure. Assuming everything works, of course, but their program is looking pretty good.

    • 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 bec

    • The amount of extra fuel required to do this is pretty trivial. The atmosphere does most of the work of slowing down the first stage, and it will be very light (because the payload and almost all of the fuel is gone) when you are trying to land it. The value of recovering the first stage greatly exceeds the slight cost of carrying a little extra fuel weight.

    • One important point that others above have alluded to but haven't outright stated:

      While the exponential scaling of rocket equation is an important limiting issue when building larger and larger rockets, for any given rocket (or rocket configuration) the payload capacity is fixed. If you have a payload that is too large for a Falcon 1Pegasus, but doesn't need the full capacity of a Falcon 9, all that extra capacity goes to waste. It costs essentially the same amount to launch a Falcon 9 at 60% capacity as it

  • Should be much easier and cheaper. Any non-technical reasons? Tax?

    • 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.

      • I agree plus it gives them flexibility. As much as Elon talks about having the first stage land back at the launch site, there's simply too much valuable infrastructure. Having a fleet of these autonomous ships gets Elon the reusability without endangering his personal and launch sites.

    • Re: (Score:1)

      by Anonymous Coward

      Very simple - the plan is, in its final stage, to let used first stages (or booster stages on Falcon Heavy) do RTLS - Return to Launch Site. That is currently prohibited due to FAA regulations and concerns at the KSC (etc. etc.) so they are not allowed to try to land on land/the KSC. For the trials, they are using the barge, that can be parked in international waters and therefore is much less subject to laws and regulations. Also, due to the different operation mode, a barge landing will still be an option

      • For a falcon heavy having a fleet of these ships would allow them to recover all three first stage elements vastly reducing the cost to put really heavy things like all the elements for a mars transfer vehicle in space.
  • Every time I read a story about the Space-X reusable rocket I can't help but wonder if they have one eye on their stated goal of going to Mars. Landing a whole rocket vertically on the surface of Mars would probably go a long way towards making a return journey feasible.

  • But our methods of getting there and back are downright comical...

  • How many times do they expect to be able to use a rocket stage before the increased risk of failure (over a brand new one) causes them to scrap it?

    • If we look at jet aircraft, wear depends on the airframe and the engines, and the airframe seems to be the number of pressurize/depressurize cycles as well as the running hours. Engines get swapped out routinely but when the airframe has enough stress it's time to retire the aircraft lest it suffer catastrophic failure. Rockets are different in scale (much greater stresses) but we can expect the failure points due to age to be those two, with the addition of one main rocket-specific failure point: cryogenic

  • I don't know why they just don't land the thing in the water. It seems like waterproofing and preventing corrosion is a lot easier to solve than the controll problem of landing on a barge. Unlike landing on the moon, landing on a barge you have to deal with wind gusts, currents, and waves. A splashdown would leave a larger margin of error and neglect the need for landing gear.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      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.

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