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posted by Dopefish on Friday February 21 2014, @05:00PM   Printer-friendly
from the rocket-kits-are-awesome-these-days dept.

WildWombat writes:

"nasaspaceflight.com reports that the next Falcon 9 flight will attempt a soft splashdown off the coast of Florida to test its newly installed landing legs. If successful, this will be a major step along the path to a reusable rocket.

The flight, CRS-3, is an ISS resupply mission scheduled for March 16th. The pace of SpaceX technology development is truly impressive."

 
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  • (Score: 5, Interesting) by calmond on Friday February 21 2014, @05:19PM

    by calmond (1826) on Friday February 21 2014, @05:19PM (#4424)
    I always wondered why they opted for the completely retro-rocket descent instead of having a helecopter style recovery once the stage 1 was subsonic. http://en.wikipedia.org/wiki/Model_rocket#Helicopt er_recovery/ [wikipedia.org]
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  • (Score: 5, Informative) by kanisae on Friday February 21 2014, @05:37PM

    by kanisae (1908) on Friday February 21 2014, @05:37PM (#4431)

    Rockets will work on Mars or Earth or most anywhere else for the full descent... helicopters are much more difficult in atmosphere of 1-3 mbars or no atmosphere at all. So what you lose in efficiency of lift, you gain in operational flexibility.

    • (Score: 5, Interesting) by NovelUserName on Friday February 21 2014, @07:03PM

      by NovelUserName (768) on Friday February 21 2014, @07:03PM (#4465)

      Since any craft landing on mars or the moon etc. would need to lift any occupants back out of the gravity well, I would assume that craft would use a different design than a final stage designed to fall into earth's gravity well and stay there.

      My guess would have been that you need a smaller mass in retro-rockets than you do in a 'copter system. Therefore it's cheaper to launch with the rocket system. This would be especially true since mass increases as cube of linear size, so the blades needed to carefully drop a Falcon9 would be proportionally huge when compared to the blades on little models like the GP linked to

      Cheers

    • (Score: 5, Insightful) by WildWombat on Friday February 21 2014, @08:29PM

      by WildWombat (1428) on Friday February 21 2014, @08:29PM (#4524)

      I think it rather unlikely that SpaceX made their design decisions for first stage return based on off Earth conditions. Its extremely unlikely that we would see an F9 first stage attempting a landing elsewhere in the solar system.

      I think the main reasons are complexity, a helicopter type system adds huge amounts of complexity and lots more things that can go wrong. SpaceX is also aiming for return to launch site capability. Helicopter type systems would require a downrange barge on which to land because you're not boosting back. This adds more cost and complexity. SpaceX is optimizing the entire system for cost. The helicopter system would probably also have a significant mass penalty, possibly more than the mass penalty for the fuel the F9 needs for the current system.

      Cheers,
      -WW

      • (Score: 4, Interesting) by kanisae on Friday February 21 2014, @09:58PM

        by kanisae (1908) on Friday February 21 2014, @09:58PM (#4567)

        Elon keeps talking about going to Mars, so I would see this as a direct ancestor to the descent stages used for a Mars landing. I mean, if you can land your rocket on a planet with 1 bar atmosphere and a 1G of surface gravity that gets you a good way to doing it on Mars with less atmosphere and less gravity.

        I would say you are correct in that this is a cost cutting measure at the moment. Liquid H2 / kerosene and LOX account for only a small part of the actual cost of a launch. Anything to get multiple uses out of the ascent stages will show a dramatic decrease in the per launch costs.

        • (Score: 2, Informative) by Kell on Saturday February 22 2014, @02:30AM

          by Kell (292) on Saturday February 22 2014, @02:30AM (#4658)

          "If you can land your rocket on a planet with 1 bar atmosphere and a 1G of surface gravity that gets you a good way to doing it on Mars with less atmosphere and less gravity."

          Except you have to lug all that landing system mass to Mars, which is terribly expensive. That's why (almost) everything landing on another planet has used parachutes and passive landing devices. It's lightweight and it's cheap.

          --
          Scientists ask questions. Engineers solve problems.