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Space Technology

Virgin Galactic SpaceShipTwo's Re-entry Tech: the Feather 62

Dutch Gun writes: When most people think about rocket science, they think of the challenge of getting a spacecraft into space. However, the problem of safely re-entering the atmosphere is a daunting challenge as well. Virgin Galactic introduces us to the concept of "the feather," their term for the combination of fixed-wing and capsule based solutions both used by spaceships in the past, and explain how they believe this hybrid approach to be a superior solution. SpaceShipTwo folds its wings in the initial decent, acting a bit like a badminton shuttlecock, when a capsule decent has the most advantages. In the latter part of the decent, the wings are extended, giving the vehicle the advantages of a glider-like landing.
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Virgin Galactic SpaceShipTwo's Re-entry Tech: the Feather

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  • by Anonymous Coward

    How can someone misspell descent three times in two sentences?

    • by myrrdyn ( 562078 ) on Monday July 20, 2015 @07:29AM (#50144253)

      How can someone misspell descent three times in two sentences?

      Missing a descent spell check?

    • "decent" is a word so the spellchecker in the browser didn't catch it. And none of the Slashdot editors can spell.
      • by 1u3hr ( 530656 )

        Slashdot editors don't use, or ignore, spellcheck anyway.

        They don't check anything really. Multiple dupes, ten-year-old stories resubmitted, obvious bogus stories, etc, etc. Offences against grammar are the least (but still irritating) of their sins.

      • *facepalm* Damn, I'm typically fairly careful about spelling and grammar, and then I screw up like that in a submission.

        Sigh... at least I'm consistent in my screwups, huh?

    • Spealled the same way both times. C- at bad speeling.

      My mom saved one of my school papers where I had missspelled the same word three different ways on the same page. That is some good speling.

  • I would still like to see a redundant parachute in case of the the mechanical failure of the the wing folding mechanism.

    Before you comment in droves about Samzenpus missing the the edit on the two "descent" fails, please proofread this post.

    • by tomhath ( 637240 )
      What kind of parachute are you going to deploy at several times the speed of sound? No chance.
      • by lgw ( 121541 )

        The initial entry is in "shuttlecock" position, which is neat because it both has an easier surface to protect and can stay thermal-armor-down without a chute or thrusters.

        The risk is that when it's time to "open" the wings and transform to plane mode, that complex mechanical stuff fails. At that point it seems useful to have a parachute. I'd wonder about the weight though - there's usually multiple chutes involved to cope with the speed, and that can get heavy (although the first chute is sometimes there

        • by tomhath ( 637240 )
          There are no wings. Either the feathers rotate back to become a stabilizer, or the craft is torn to pieces (see video of the most recent failure).
    • by 1u3hr ( 530656 )
      3 "decent" fails actually.
    • I would still like to see a redundant parachute in case of the the mechanical failure of the the wing folding mechanism.

      A redundant parachute would be worthless. Deploying a parachute at supersonic speeds from an spacecraft will simply make confetti. The unfeathered spacecraft likely would be torn to pieces before it could slow down to speeds where a parachute might be effective, hence the problem.

      The feathering mechanism, like many things in engineering, simply must work without fail as there is no plausible backup option. Failure of the feathering mechanism means likely loss of crew and vehicle.

      • You know, you're correct in saying if they wings don't close, well then, you're proper fucked.

        The parachute is for if they don't reopen, after shuttlecock mode has done it's job.

        • You know, you're correct in saying if they wings don't close, well then, you're proper fucked.

          The parachute is for if they don't reopen, after shuttlecock mode has done it's job.

          True, good point. Though, with a parachute, there needs to be some clear abort envelopes and interlocks in place to prevent parachute deployment at an inappropriate time.

          Adding backup systems increases the complexity of the system as a whole, and can sometimes introduce more failure modes, actually decreasing the overall safety of the system. Having a simple system with no backup can actually be the safest arrangement. It depends on whether you want to gamble with an 0.01% chance of a completely unsurvivabl

  • you initiate the feather to soon and cause the spaceship to break up.
    • Re: (Score:2, Insightful)

      by Anonymous Coward

      That's nice. Is there any stage in the rocket launching/landing that one can do too soon without a spectacular failure?

      • by Anonymous Coward

        potentially the first stage... but you need to move up the timetable on the other ones if that happens.

    • by dtmos ( 447842 ) *

      you initiate the feather to soon

      . . . or even too soon.

  • by NotDrWho ( 3543773 ) on Monday July 20, 2015 @07:39AM (#50144289)

    For those interested, the documentary Black Sky [imdb.com] is a must-see on explaining how this concept (and SpaceShipOne in general) works.

  • by Anonymous Coward on Monday July 20, 2015 @07:40AM (#50144299)

    Branson and Virgin did nothing at all except provide funding after the fact to the actual, certified genius aerodynamist and visionary Burt Rutan.
    Since it is far outside the knowledge domain of /., I will just introduce Rutan to the crowd who might be attracted to the silly clickbait article: Burt has for about
    40 years years been designing outstanding aircraft, some large, most small. He designed for NASA, for Jim Bede, and for thousands of home builders. He pioneered the modern use of canard winds and composite construction. He designed many famous aircraft including SpaceShipOne and its unique tail feathering.

    • Re: (Score:3, Insightful)

      by dimeglio ( 456244 )
      You are greatly diminishing the importance of funding.
      • by Anonymous Coward

        You are greatly diminishing the importance of funding.

        And you are greatly diminishing the ability of Branson to be self-aggrandizing.

        I call it a tie... Branson's a egotist with money, and engineers are unappreciated, and awesome.

      • The funding would be for SS1, which was Paul Allen. SS2 is simply trying to use the same tech and VG fucked it up.
    • Branson and Virgin did nothing at all except provide funding after the fact to the actual, certified genius aerodynamist and visionary Burt Rutan.

      Determining what to fund and what not to fund is basically the hardest problem ever. If you could give me a computer program that can determine quickly and correctly what to fund and what not to fund, I could make the next revolutionary product, discover all the laws of physics, and discover proofs to mathematical problems.

  • by mightypenguin ( 593397 ) on Monday July 20, 2015 @07:52AM (#50144349)
    I have serious doubts that a feathered reentry would work for anything that has orbital reentry speed. There's a reason we have capsules with heat shields, and it's still tricky. We lost a shuttle over damaged heat shields. I suspect there would be strong vibration issues at orbital reentry speed as well that they haven't had to face yet since all of their flights so far (as well as those actually scheduled) have been sub-orbital. That being said, I wish them luck and hope they continue to innovate.
    • Re: (Score:1, Informative)

      by Anonymous Coward

      All SpaceshipTwo flights will be sub-orbital.

    • I think the feathered reentry would still work at orbital speeds, it's just that the composite material from which SS2 is built can't withstand the heat. Putting heat tiles on SS2 would not work well as that would add too much weight, and they're still gonna have all kinds of problems with the tiles staying in place. So for all intents and purposes the feather reentry is strictly a suborbital design.

      The most innovative orbital reentry design I saw was a proposal for using the rocket engine plume to deflect

  • Very nifty, but... (Score:5, Informative)

    by necro81 ( 917438 ) on Monday July 20, 2015 @08:03AM (#50144401) Journal
    The feathering mechanism is very clever and effective, and I'm sure that Richard Branson and Virgin Galactic love getting free advertising on Slashdot. But this concept - the mechanism, the shuttlecock behavior, the passive stabilization - was successfully demonstrated when SpaceShipOne won the X-Prize ... in 2004.

    So please explain, Oh submitter and editors, why are you cluttering up our lives with old news?
    • So please explain, Oh submitter and editors, why are you cluttering up our lives with old news?

      Because scaling supersonic aerodynamics up to a spacecraft with twice the size is nontrivial?

      • by necro81 ( 917438 )

        Because scaling supersonic aerodynamics up to a spacecraft with twice the size is nontrivial

        I'll grant you it is a nontrivial problem, and being able to make it work on a larger vehicle is a slick piece of engineering. On the other hand, the video presents nothing new about those aerodynamics, nor any of the challenges they needed to solve to maintain the concept in SpaceShipTwo. Instead, to use a car analogy, the video goes something like "motorcycles have two wheels, cars have four. Ours product is c

        • by jimbo ( 1370 )

          Oh the intolerance, you sound like a Redditor... Speaking of which; I dislike the rampant abuse of car analogies when your position is easily explained/understood, even if it is a popular practice here.

          Anyway, I know about SpaceShipOne, Rutan and how feathering works but I don't mind the occasional re-post because sometimes I miss posts and sometimes something is just cool and I enjoy being reminded of it years later. If I'm not interested, I scroll past it. As long as re-posts are not flooding the site I'm

  • What's the news in this? This has been Virgin's approach for many years now, and it's very interesting, but what brought this to the front page today? Did something change?
    • Could it have something to do with the National Transportation Safety Board's inquiry into the October crash? I heard that the NTSB is going public with some of the hearings soon.
      • by asylumx ( 881307 )
        Maybe. The only link in TFS goes to a short blurb and a video from Virgin about how feathering works, which is nothing new either. I still don't understand what made this news all of a sudden.

        It's pretty cool and all, I just don't get why this story on Slashdot exists. Most slashdotters have known about this technique for years, since it was explained by Virgin the first time.
  • First of all, this is really old news. SpaceShip One no longer flies and has been a museum piece for years, and Virgin's burned their bridges with Scaled Composites and thus made it a lot less likely that they will be able to mount a near space effort with the SpaceShip Two design.

    Second, this is not an orbital re-entry system, because it's not well-suited for a heat shield and thus can't do the necessary atmospheric braking. It's just a system to get you back from high altitude suborbital flights.

  • by Dunbal ( 464142 ) * on Monday July 20, 2015 @10:39AM (#50145427)

    However, the problem of safely re-entering the atmosphere is a daunting challenge as well.

    Yes this is especially true since they updated Kerbal Space Program manager to 1.02...

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