Follow Slashdot blog updates by subscribing to our blog RSS feed

 


Forgot your password?
Close
typodupeerror
×
Space

SpaceX Breaks Down Its Rocket Landing Attempts 72

Posted by Soulskill from the third-time's-a-charm dept.
An anonymous reader writes: Twice now, SpaceX has attempted to land one of its rockets on a barge in the ocean after it delivered a payload to orbit. Each attempt came very close, and provided some fascinating imagery. In a new post on their website, SpaceX explains where they're at with rocket landing technology, and what went wrong with the earlier trials: "That controlled descent was successful, but about 10 seconds before landing, a valve controlling the rocket's engine power (thrust) temporarily stopped responding to commands as quickly as it should have. As a result, it throttled down a few seconds later than commanded, and—with the rocket weighing about 67,000 lbs and traveling nearly 200 mph at this point—a few seconds can be a very long time. With the throttle essentially stuck on 'high' and the engine firing longer than it was supposed to, the vehicle temporarily lost control and was unable to recover in time for landing, eventually tipping over." They believe they've solved the issues that cropped up in the earlier tests, and they're looking forward to the next attempt, which will happen on Sunday if the weather cooperates.
This discussion has been archived. No new comments can be posted.

SpaceX Breaks Down Its Rocket Landing Attempts More

SpaceX Breaks Down Its Rocket Landing Attempts

Comments Filter:

  • Java? (Score:5, Funny)

    by Rinikusu ( 28164 ) on Friday June 26, 2015 @03:33PM (#49997979)

    I just got an image of them using Java as their primary control language and the gc decided to collect at the last moment...

  • Why don't they just build a big net on the barge? If it doesn't land straight up and down, or if it falls over it won't matter. And if the rocket thing doesn't work out maybe they can still catch some nice tuna.

    • Re:Since they are on the ocean... (Score:4, Informative)

      by cjameshuff ( 624879 ) on Friday June 26, 2015 @04:15PM (#49998321) Homepage

      Rockets are fragile, they can't take much mistreatment. A net would at most catch some debris...they don't want debris, they want a rocket. And in normal operation, they should be able to soft land upright on the platform, so a net would be an unnecessary complication in the best case...in the worst case, the net system gets in the way and causes a landing failure.

    • Re: (Score:2)

      by Kjella ( 173770 )

      Have you seen the footage where it falls over? Then it hits hard, the remaining fuel sparks and it goes boom way past recovering anything but scrap metal. If they want something that's worth salvaging, it has to land smooth. Also the net wouldn't really help with the first 99%.

    • Re: (Score:3, Insightful)

      by TechnoCore ( 806385 )
      Musk has said he wants to do it in style. I think what he means is that if they cannot prove they can do it perfectly, then USAF, and FFA won't allow them to land on land, which is the ultimate goal. Since barge landing will always be dependent on weather. Also, the first stage is much like a soda can. Very very thin aluminum. If it falls on something, or there is a small chance it has been damaged in any way, refurbish costs would become expensive. What he wants is to drive down launch costs, and to do tha

  • SpaceX Breaks Down... (crap, what happened now?)

    its rocket landing attempts. Ah, alright then, never mind. Got me worried for nothing.

    • Why is is that after more than fifty years of progress, the United States is taking more time to put humans into orbit than it took to go to the moon? I would think that our ability to put humans in the ISS would be a far greater priority than saving the first stage of an unmanned launch.

      • Why is is that after more than fifty years of progress, the United States is taking more time to put humans into orbit than it took to go to the moon?

        Two reasons, really.

        1) We spent money like water on the moon race.

        2) We really don't care about putting men in space these days.

        Okay, 3 reasons:

        3) Two shuttles full of dead people in a risk-averse society. We've gotten so we get panicky when people die, especially when they do it on TV. So we're insisting on an insane level of perfection for putting p

  • Brilliant marketing (Score:1)

    by Anonymous Coward

    This is a genius stroke of marketing. Rocket launches are nothing special anymore (besides figuring which of the next three next Russian launches will fail due to incompetence). By focusing on the part of the launch that is wholly inconsequential, people pay them far more attention than they would for an otherwise uninteresting successful launch.

    • Re: (Score:2)

      by 605dave ( 722736 )

      Did you even read what they wrote? Reusing a rocket would have enormous economic advantages. This is hardly a publicity stunt.

      • Dude, you just got trolled by a guy stuck working for ULA. Just tell him to ratchet up the 401(k) contributions and go back to his expensive, late, old-tech rockets.

  • If this software can bring down a rocket safely, could it bring down a plane safely? Could completely self-fly planes be in the wings?

    • That's old hat. It's already been done, and what's more, they've landed them on an aircraft carrier:

      https://en.wikipedia.org/wiki/... [wikipedia.org]

    • Planes have been flying and landing themselves for decades now. Pilots are there to transition the flight from one automated task to another depending on conditions and instructions from control centers and towers. They are also a backup in case of system failure. A modern airline pilot probably manually controls the aircraft for less than 1% of any given flight but really doesn't have to. He can instruct the flight computer to do all of these tasks if he wishes. Depending on the airline, pilots are require

      • Using human pilots to "transition the flight from one automated task to another" is not self-flying, and the person above you linked the NG X-47B [wikipedia.org] which is only capable of semi-autonomous flight.

  • > but about 10 seconds before landing, a valve controlling the rocket's engine
    > power (thrust) temporarily stopped responding to commands as quickly as it should have.

    "The OS support engineers at Microsoft still maintain we are not one of the very few applications that really need true real time."

  • Falcon Heavy will land 3 boosters per mission (Score:5, Interesting)

    by frank249 ( 100528 ) on Friday June 26, 2015 @05:44PM (#49999011)

    Check out this video of Falcon Heavy [spacex.com]. They plan to land and reuse all 3 boosters at the landing site they have leased at the Kennedy Space Centre [nasaspaceflight.com]. Saving 9 engines from a Falcon 9 is a considerable savings but saving all 27 engines from a Falcon Heavy launch would bring the cost per kg down to perhaps $100.

    • The video has them all landing together largely for dramatic effect (or to avoid modeling an ASDS). For most real launches, the center core will be much too far downrange and moving too fast to return to the launch site, and will have to land on an ASDS positioned out at sea. The smaller side pads are intended as fallbacks in case the center pad is unreachable or otherwise out of commission. They'll probably use two ASDSs for the center and one side core until they get a second land-based landing site const

    • Saving 9 engines from a Falcon 9 is a considerable savings but saving all 27 engines from a Falcon Heavy launch would bring the cost per kg down to perhaps $100.

      Slashdot is filled (at least theoretically) with smart people... so why do I have to keep explaining this?

      It's virtually impossible to determine how much recovery will bring down the costs of launch because we don't know how much it will cost to refurbish the recovered vehicle. Certainly it will be cheaper than building a new one, but how much ch

      • 'It's virtually impossible to determine how much recovery will bring down the costs of launch because we don't know how much it will cost to refurbish the recovered vehicle. Certainly it will be cheaper than building a new one, but how much cheaper is impossible to predict... especially in the beginning with zero experience.'

        I am going by what SpaceX themselves have estimated.Reusable Falcon 9 Would Cost $5 to $7 Million Per Launch [parabolicarc.com]. 13,000kg to LEO at that price is $500/kg or $209/lb. Falcon Heavy's payl

        • That sound you heard was my point zooming over your head.

          I am going by what SpaceX themselves have estimated.

          Estimates are not reality - even if you do have the experience to base your estimate on. Experience SpaceX lacks.

          They plan to inspect, refuel and relaunch in a matter of days so those costs will be minimal.

          Plans are not reality. See above about experience.

          Remember the boosters are not going into space nor the stress of reentry.

          You say that as if it's relevant. It's not. The structure is still

  • Could somebody explain the reasoning for this? Landing on the ground would make more sense to my limited knowledge. Thanks

    • I'm going to assume you've been doing the /. equivalent of living under a rock, since this question comes up (and gets answered) every single time this topic is discussed, and that's a lot. But what the hell...

      Landing on solid ground is, generally, preferable. However, unlike the ocean where you can tell all the boats to get out of a safety zone, land has these inconvenient things like buildings and infrastructure that can't simply be told to stay away for their own safety. Until it was clear how precisely SpaceX could bring the rocket down - and remember, we're talking about something returning from the edge of space, at supersonic speeds, with barely any fuel remaining, in a maneuver that had never been attempted before - it would have been foolish to bring the rocket down anywhere near any inhabited regions. Given the geography around the launch sites they use, that means the ocean is the best bet by far.

      Also, sometimes they may not have a choice. The rocket *really* doesn't have a lot of fuel left as it returns, and it's going really, really fast in a direction that is decidedly away from the launch site (but not fast enough to make it all the way around the world, or the second stage wouldn't be needed to actually achieve orbital velocity). SpaceX pulls a lot of cool tricks to guide the rocket's return, like using the stage as a lifting surface (with a truly abysmal lift/drag ratio, I assume, but they're also trying to scrub speed) while controlling it with little folding grid fins (which are quite effective at those speeds). However, at the end of the day, even Falcon 9 may not have the fuel margin to return to the spaceport after launches even though it has enough fuel to launch *somewhere*. The center core of the Falcon Heavy - which flies for much longer than the F9 first stage - will be much too far downrange to boost back to the spaceport in most cases. Thus, for FH's center core, the barge may be the only landing option. Landing on a ship may be harder than landing at a conventional spaceport, but the ship can be almost anywhere there's ocean, while land-based spaceports are not noted for their mobility.

      Now, with all that said, the goal is to, eventually, be able to land at the spaceport. The next F9 launch after this one will, according to a cool site called SpaceX Stats [spacexstats.com], attempt to return to the launch site and land there. This presumably demonstrates that SpaceX has been found to have sufficient precision in the first-stage landing attempts so far for it to be safe to land near people and expensive buildings. I wish them the very best of luck!

    • There's probably fewer things to worry about blowing up or catching fire out in the ocean.

      You know, someone could get poked in the eye otherwise. ;-)

  • ... is why they insist on trying to land it on its feet. It's not like it's going to be taking off seconds after. Why not land it in a material or construction that can take a hit and not care so much about whether it is perfectly upright at the last seconds? It almost looks like Hollywood putting rocket shoes on their stuntmen, instead of having them land in a net, on cardboard boxes or a nice air cushion...

  • I love that they found time to name the drone ships in true Iain M. Banks' Culture style: “Just Read the Instructions” & “Of Course I Still Love You”

Slashdot Top Deals

Every nonzero finite dimensional inner product space has an orthonormal basis. It makes sense, when you don't think about it.

Close