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SpaceX's Latest Launch Successful, But Ends With a "Hard Landing" (theverge.com) 129

Posted by timothy 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.
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SpaceX's Latest Launch Successful, But Ends With a "Hard Landing" More

SpaceX's Latest Launch Successful, But Ends With a "Hard Landing"

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  • Expectations game (Score:5, Funny)

    by ratnerstar ( 609443 ) on Saturday March 05, 2016 @11:18AM (#51643505) Homepage

    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!

    • They're managing expectations with 'crash euphemisms'.

      Shame my car insurers won't accept I just 'parked it hard'.

    • Re: (Score:2)

      by Kjella ( 173770 )

      The difference is that one of them scores a win in their primaries. Yes, eventually SpaceX has to reliably nail their landings to make it useful but it was a first for this type of mission and they still almost reached their stretch goals while adding yet another successful satellite delivery to the Falcon 9 reliability stats. So apples and oranges, IMHO.

      • they still almost reached their stretch goals

        I don't think it was "almost." That describes the landing when the first stage touched down then tipped over. This sounds like it was not even close to a soft landing.

        . So apples and oranges, IMHO.

        Yes, comparing a politician's primary campaign and a rocket launch is definitely "apples and oranges."

        • Re:Expectations game (Score:4, Interesting)

          by Teancum ( 67324 ) <robert_horning AT netzero DOT net> on Saturday March 05, 2016 @02:57PM (#51644409) Homepage Journal

          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.

    • Re: (Score:1)

      by AmiMoJo ( 196126 )

      Didn't Blue Origin already do this a while back anyway? They landed a rocket... Okay, this is at sea, but Blue Origin are reusing their's. It's interesting but seems like Musk is really hyping up second place.

      • Re:Expectations game (Score:5, Insightful)

        by Rei ( 128717 ) on Saturday March 05, 2016 @03:28PM (#51644591) Homepage

        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.

        • Re: (Score:2)

          by Teancum ( 67324 )

          I couldn't have said it any better, other than landing on that pogo stick on a raft in the middle of a swimming pool.

          Besides, it was SpaceX that made the first attempts on that concept too. Blue Origin just took an easier to accomplish task (aka the sub-orbital) and did it earlier.

          Or if you want to give credit where it is due, the thanks goes to the DC-X team who was successful in landing a suborbital flight like that.

          • Re: (Score:1)

            by Anonymous Coward

            Credit for the software architecture goes to John Carmack of Doom fame during his time at Armadillo Aerospace.

            They aren't using your fathers autopilot, the new software is hardware agnostic and self adjusting in real time. Falcon 9 is probably the most "intelligent" aircraft to ever fly, capable of managing everything from last second post ignition scrubs to engine out events without help from ground control. SpaceX is hands off minutes before liftoff, they trust their hardware, their crazy smart hardware.

            C

            • Re: (Score:2)

              by Teancum ( 67324 )

              You are 100% correct on every point above, at least based on stuff I have heard about from SpaceX from a variety of sources.

              Switching to an internal TCP/IP network for the rocket also saved a tremendous amount of mass for sensor cabling too, which matters a whole ton more when you are talking about the rocket equation.

        • It's really mostly about speed and kinetic energy.

          The Blue Orbital New Shepard first stage and the Falcon 9 first stage are both suborbital vehicles, but the F9 is faster and way more energetic in terms of energy per unit of mass. Here are some numbers:

          New Shepard first stage
          Speed at MECO: 1250 m/s
          Kinetic energy per kilogram: 0,8 MJ

          Falcon 9 first stage, LEO launch
          Speed at MECO: 1650 m/s
          Kinetic energy per kilogram: 1,4 MJ

          Falcon 9 first stage, geostationary launch:
          Speed at MECO: 2250 m/s
          Kinetic energy per kil

          • Re: (Score:1)

            by Rei ( 128717 )

            Basically, if they wanted to make New Shepard comparable, they'd have to get the payload fraction inline by cutting its mass down to, what, a third of its current mass? Then they'd have to eliminate the ability to hover (because the engines need too much thrust in an actual orbital rocket - Falcon 9 shuts down all but one of their engines and throttles it down to 70%, and it's still too much thrust), and have it attempt its landing from a far higher delta V, onto a tiny platform in the ocean.

            Yeah, good luc

        • Re: (Score:2)

          by AmiMoJo ( 196126 )

          Thanks for pointing that out, but you could just say it without the snark you know.

      • See this comparison including handy graphic: http://www.popularmechanics.co... [popularmechanics.com]

      • SpaceX has already landed a rocket on land as well, they just want to get the sea landings down, because not every launch allows landing on land.

  • Right now, both of the barges have horizontal thrusters that will keep the barges in 1 place. In that regard, it makes much easier for the craft to come down. However, the barges do not have vertical thrusters, so, they will pitch and roll in the same location. Without these, it is going to be impossible for these to land on the barge during heavy seas such as what was seen. On a calmer day, with say 1 m waves and under, the stages will do just fine.

    • Since you can't call up Poseidon and order some calm seas, this is a problem they're going to have to fix sooner or later.

      • Re: (Score:2)

        by chill ( 34294 )

        Threaded conversations are fun. Since you didn't quote the original, your use of this as a pronoun refers to having to figure out how to call up Poseidon and order some calm seas.

        Sir, your ideas are intriguing to me and I wish to subscribe to your newsletter. I wonder if we can get a Federal grant for research efforts into replicating Triton's conch horn [wikipedia.org]?

      • A deep keel would help with stability. Since their ships are barges, I assume they have no keels. When I was a Marine, I spent quite a bit of time on amphibious ships (aka "gators") which also have no keels, so they can get in close to the shore. They rolled a lot in rough seas, and I spent many days puking over the railing.

      • Re: (Score:2)

        by k6mfw ( 1182893 )

        Since you can't call up Poseidon and order some calm seas

        wow, this reminds me Poseidon is a god and not a trademark name of Lockheed.

    • Re: (Score:2)

      by short ( 66530 )
      If they were confident they can land it safely they could wait multiple launch windows until the sea is calm.

      • About the only issue I can see, from a commercial point-of-view, is that those delays may mean I have to wait for my satellite to be operational. You need to have "perfect" weather now in two places across the globe.

        • Satellites take years to develop, and sometimes sit on a shelf for years more before they get a launch slot. Waiting a few days/weeks for "perfect" weather is nothing compared to that. I imagine launch customers look at the criteria in the following order, First that their satellite makes it to orbit, secondly that it is done so as cheaply as possible, and a distant third that it is launched on time. The only exception might be some interplanetary launches, but in with a properly designed propulsion syst

    • Right now, both of the barges have horizontal thrusters that will keep the barges in 1 place. In that regard, it makes much easier for the craft to come down. However, the barges do not have vertical thrusters, so, they will pitch and roll in the same location. Without these, it is going to be impossible for these to land on the barge during heavy seas such as what was seen. On a calmer day, with say 1 m waves and under, the stages will do just fine.

      If the ship itself is stationary in the horizontal plane then all they really need to do is to make sure the platform on to of the ship is horizontal and not moving in the z-axis.

      They could probably mount the platform on top of some actuators that could compensate for the motion in the z-axis.

      • On the Reddit spacex forum, the moderators aren't allowing posts with back-of-napkin engineering like this any longer. You need to present the math. They are doing that because we've heard all of the suggestions before and we're totally bored with them. Nets. Moving platforms. Big foam yonis. A big crane that grabs the rocket really fast. Giant baseball gloves.

        One would hope the rocket itself could handle up-and-down motion of the barge. It has a radar altimeter and a computer.

        • Your idea should be fairly easy to do the math on, if you have the data on the Merlin engine. Can the Merlin engine ramp up thrust fast enough to compensate for a rising ocean wave at the last moment? I doubt that data is publicly available, thought.

          If you had data on the weight distribution of the first stage and the mechanical characteristics of the landing legs you could also run simulations to see if the stage would tip over and fall in heavy seas after a successful landing. Again, I doubt you can get t

          • There seems to be a lot of inside information flowing to at least one of the Reddit moderators. Even lowly I have had my tour of the SpaceX plant. :-)

    • Re: (Score:2)

      by Kjella ( 173770 )

      Right now, both of the barges have horizontal thrusters that will keep the barges in 1 place. In that regard, it makes much easier for the craft to come down. However, the barges do not have vertical thrusters, so, they will pitch and roll in the same location. Without these, it is going to be impossible for these to land on the barge during heavy seas such as what was seen. On a calmer day, with say 1 m waves and under, the stages will do just fine.

      Heavy seas and heavy winds tend to go together, the main issue is that you're bringing down a huge, mostly empty cylinder that'll get caught by the wind. If they can compensate for that they certainly can compensate for a pitching/rolling surface. It's been pretty clear from past failures that it's the rocket failing to make a good touchdown, not the ship acting up. Including the one where the landing leg didn't lock. Until SpaceX start showing footage of rockets coming down so soft they "should have" lande

      • 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.

        • Hoverslam is certainly a challenge, but even if they could throttle the engines to arbitrarily low levels they would still probably use a similar descent profile. It's inefficient to hover or come in gently - the best possible (read: most efficient) descent is the "suicide burn", where you wait until the last millisecond and then go full thrust. So, even if they didn't have to hoverslam because of throttling constraints, they would probably still do it to save fuel.

      • That is not entirely accurate. What was announced is mostly guess work. In addition, so far, the only constant landings are on stable land, while medium to rough seas seems to have all sorts of mechanical issues, but it is never the barge's motion.
        However, if I were musk, the last thing that I would do is tell the world exactly what is wrong and how we solved it.

    • Re: (Score:1)

      by Mryll ( 48745 )

      It reminds me a little bit of an ill-fated stunt on the ill-fated program "Stunt Junkies" where a guy wanted to jump a motorcycle from one barge to another. Caught enough of a vertical difference between the barges to barely but completely overshoot his landing ramp, landed horizontal, and broke a bunch of bones in his back. Touchy stuff on a relatively simple trajectory.

    • I still think, that the future holds a permanent landing pad structure built in the ocean. There are parts of the sea floor in the right area that a significantly shallower than some of the depths oil platforms operate at.

      Whether this happens or not will be down to how re-usable the rockets are of course. But if they, for example, allow a 75% cost reduction, then the economics of building a platform for recovery are probably there.

      • This is problematical, because it freezes a whole bunch of parameters. It means you can't aim for your orbit, you have to aim for your re-entry destination instead. Orbital inclination, speed, and the length of the burn must be exactly what is necessary to hit that platform. Especially for high-delta-V missions like this last one, where there isn't enough fuel for a boost-back burn and the barge was 600 kM downrange.

        • You know the stage does course corrections after separation right? The barge doesn't just happen to be sitting where the stage will land by default. I suspect that at the speed and altitude that separation occurs there is a significant arc the rocket can land in with marginal difference in fuel use. The fins alone will give significant steering capabilities.

          Yes for some launches, such as this one, the amount of available fuel will be extremely limited and you may decide to use a barge in that instance bec

          • The SES-9 re-entry really was ballistic. Only low-energy missions have the fuel to do a boostback burn, even lower energy if you want to return to launch site, and Falcon 9 Heavy can't return the center stage to launch site because it goes too far down-range. In general they need the barge to be where the rocket will come down, so that recovery does not impinge on mission fuel. A stationary platform is too containing, too expensive, and it only solves one problem: vertical motion. Vertical motion is not so

            • I'm not talking about boosting back to the starting point. Also SES-9 had less fuel than the original mission spec because Space X punted the satellite out a lot further than the original plan, it would be a prime candidate to remain a barge landing or just a rocket you don't even try to catch. Ideally it would be the xth launch for that particular first stage where the rocket cost was already well and truly covered.

              Also one has to assume that rockets will get more powerful as they develop meaning a wider

              • I think SpaceX will sell a lot more geostationary transfer orbit missions now. They've shown that they can do it with a pretty heavy payload: 5300 kg, and they delivered 1300 km greater apogee than promised.

                Your cost figure for building a recovery platform is for one of them. So, suppose that one would work for GTO on F9. To limit the delta-V needed for recovery, you'd probably need another for GTO on F9H center stage, because it gets a lot higher and further downrange, one for LEO insertions that can't ret

                • I could be very wrong, but I thought polar launches had a potential land landing site. As for the multiple landing points, I wouldn't initially try to recover something like the most recent launch. Not enough fuel left for control and it is at the maximum end of the range spectrum. Also who knows about the center stage, I was only thinking about the first stage.

                  As for the differences between ISS launch and LEO etc, how much difference is there between them at the point of stage 1 separation? (I genuinel

                  • I thought polar launches had a potential land landing site.

                    San Nicolas Island, California, is an offshore navy landing strip which I've speculated about but I've not seen any official word from SpaceX. It's about half the distance from LA that they positioned the barge, perhaps uncomfortably close to LA as far as range safety is concerned.

                    I am dubious that any platform in deep water stays in one piece without continuous attention. The British ones that have survived, more or less, since World War II are in

    • I don't believe "vertical thrusters" are practical because you would either be lifting the barge's entire weight into the air or pushing its entire displacement under the water. And it weighs a few hundred tons. You might mean "stabilizers", which are used to prevent rocking in cruise ships and are essentially underwater wings.

      It might just be that a slow cyclical 20-foot vertical motion isn't a challenge to landing with radar altimetry. It's not likely to tip the rocket, either, because the empty rocket i

      • Quite the opposite. Fins are only good for ships underway. When they are stationary or the water is moving that slow, then the fins are worthless.
        OTOH, VERTICAL STABILIZERS, or vertical thrusters, can and are used in various systems (namely a number of floating oil rigs). They will not stop the roll and pitch, BUT, they will limit it under the right conditions. And that is what is needed. Basically, the barge needs to have limited pitch.

  • Would there be benefit in trying to land the rocket in a pool of fresh water (or even pure water or some other non-ionizing solution)?

    It would at least be less corrosive than salt water, and if they get it out quickly maybe not significantly damaging at all?

    • Re: (Score:2)

      by Eloking ( 877834 )

      Would there be benefit in trying to land the rocket in a pool of fresh water (or even pure water or some other non-ionizing solution)?

      It would at least be less corrosive than salt water, and if they get it out quickly maybe not significantly damaging at all?

      Hmmm I don't think it'll work.

      First, you'll probably need to stop the rocket at the surface of the water, it'll will have the time to gain a lot of momentum while it enter.

      Second, the rocket will now slow down that much if it enter the water vertically, you'll probably have to figure a way to deploy a short of water parachute (which will add some weight).

      Thirdly, those rocket are quite fragile so, even if the drag of the water will slow the rocket a bit, I'm quite sure it'll be damaged if it tip over and fa

      • They can do a landing on solid ground (or at least they have done it once). Unfortunately, there is no solid ground in the right place for most flights

    • Big hot rocket engines and nozzles crack when immersed in cold water.

  • 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.

    So their design allows them to send heavy loads into orbit but that requires so much fuel that they can't land it afterward.

    So either don't launch things heavier than X, or increase the fuel capacity. It's not rocket sci... oh wa

    • There are many different loads and orbits. The rocket can launch a lighter load or a lower orbit, and make a successful return, or it can launch a heavy load into a higher orbit, and act as a standard disposable rocket. Once they get a routine started, they can relaunch a rocket multiple times, and when it starts to wear out, use it for one last disposable launch.

    • Re: (Score:2)

      by Guspaz ( 556486 )

      There was originally supposed to be enough fuel for the landing. The way it works is that they normally put the satellite in a transfer orbit, and then the satellite moves itself to the final orbit, kind of a third stage of the rocket. That's very slow, however. SpaceX was months behind schedule, so they promised to put the satellite into a much closer to final orbit to shave around a month off the required orbital maneuvering. Unfortunately, that used up the extra fuel reserved for landing.

      Had they not bee

      • Not only were they months behind schedule, but they got SES to switch places with Orbcomm, so that they could return to flight with a simpler mission. So, they really owed SES.

  • The use of superchilled liquid oxygen was a big step for them. Making the fuel denser allows them to put more fuel in the same volume.

  • How's that barge landing thing working out?

  • Falcon Heavy [wikipedia.org] will benefit most from the reusable technology. It uses two Falcon 9 first stages as boosters. The flight profiles will allow the two boosters to land back at their landing pad. They also have the option of recovering the central on the drone ship which is harder but we can see that they are getting closer with each attempt.

  • I postulate why? Isn't there enough land to land on?

    Wasn't the original idea of ending up at sea was so they could soft-splash in the water?

    • Re: (Score:2)

      by aslagle ( 441969 )
      Sea landings play merry hell with the equipment, requiring lots of expensive refurbishment (ala the shuttle booster rocket segments). The SpaceX approach is to bring the boosters to a soft touchdown on land, minimizing turnaround costs.

    • I postulate why? Isn't there enough land to land on?

      No. Or at least not in the right places.

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