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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: -1, Offtopic) by aliks on Friday February 21 2014, @05:03PM

    by aliks (357) on Friday February 21 2014, @05:03PM (#4418)

    Couldn't resist!

    Mod me down

    --
    To err is human, to comment divine
  • (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]
    • (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.
  • (Score: 2, Interesting) by cmn32480 on Friday February 21 2014, @07:26PM

    by cmn32480 (443) <reversethis-{moc.liamg} {ta} {08423nmc}> on Friday February 21 2014, @07:26PM (#4488) Journal

    I am no rocket scientist, and I apologize for the very basic question.

    What, exactly, is the purpose of the landing legs? Is it really as simple as I think it is, like landing on the moon with the legs on the lunar module?

    --
    "It's a dog eat dog world, and I'm wearing Milkbone underwear" - Norm Peterson
    • (Score: 4, Informative) by kanisae on Friday February 21 2014, @07:46PM

      by kanisae (1908) on Friday February 21 2014, @07:46PM (#4498)

      SpaceX wants their rockets to be fully re-usable, so the purpose of the legs is exactly that, to land land the rocket after launch.

    • (Score: 2, Informative) by amblivious on Friday February 21 2014, @07:55PM

      by amblivious (26) on Friday February 21 2014, @07:55PM (#4502)

      The addition of landing legs is one of the steps on the path to building a fully reusable rocket.

    • (Score: 5, Informative) by WildWombat on Friday February 21 2014, @08:22PM

      by WildWombat (1428) on Friday February 21 2014, @08:22PM (#4521)

      Yes. This flight they are going to test the leg deployment and make sure they can land softly and accurately. Once they've proven that the system works they'll attempt landings on solid ground instead of water. They want to be able to reuse the first stage and this is a step in that direction. This has always been a goal of SpaceX and they designed the rocket and the engines with re-usability in mind.

      Cheers,
      -WW

    • (Score: 5, Informative) by sar on Friday February 21 2014, @09:12PM

      by sar (507) on Friday February 21 2014, @09:12PM (#4548)
      There is video with test flight demonstrating this cool technology: http://www.space.com/23193-spacex-grasshopper-rock et-highest-hop-video.html [space.com]
    • (Score: 1) by tibman on Saturday February 22 2014, @12:18AM

      by tibman (134) Subscriber Badge on Saturday February 22 2014, @12:18AM (#4620)

      The rocket legs will be mostly used for crushing every competing rocket system ever designed. Instead of just crashing back to earth the rocket will land!

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  • (Score: 4, Interesting) by bigjimslade on Friday February 21 2014, @09:26PM

    by bigjimslade (212) on Friday February 21 2014, @09:26PM (#4555)

    ...The pace of SpaceX technology development is truly impressive...

    I would expect that, given they are working their staff to death.
    Talked with a few engineers that have left; one just got off a 140 hour work week, which drove him to leave. not sure there is much choice for aero engineers, though.

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    • (Score: 3, Funny) by Blackmoore on Friday February 21 2014, @10:05PM

      by Blackmoore (57) on Friday February 21 2014, @10:05PM (#4572) Journal

      So, it really was like working for a bond villain?

    • (Score: 0) by Anonymous Coward on Friday February 21 2014, @10:30PM

      by Anonymous Coward on Friday February 21 2014, @10:30PM (#4581)

      140 hours? That's 4h/day off work. I hope he slept in the office because otherwise his commute would eat up half of his sleep time. Crazy.

  • (Score: 5, Interesting) by dr_zaius on Friday February 21 2014, @11:21PM

    by dr_zaius (1139) on Friday February 21 2014, @11:21PM (#4598)

    SpaceX is already shaking up the launch market with costs significantly below the competition -- roughly $54 million to low Earth orbit on an expendable Falcon 9. If the first stage can be made reusable, launch costs to low Earth orbit could potentially be driven down to $10 million or less. Even lower if the second stage can be made recoverable as well. Fuel costs are a vehicle such as the Falcon 9 are in the range of $300,000. Therefore the great majority of expense in a launch is in the boosters which up until now are discarded and can't be amortized over time.

    Reusable rockets could potentially open up space just as the railroads once opened up the West. An expendable rocket is like a train that is discarded once it reaches its destination. A reusable rocket allows access to space to operate on the same economics of a train that transfer goods over and over again for the cost of maintenance and fuel. This would be a revolutionary change in the economics of getting into space.

  • (Score: 2, Funny) by Boxzy on Saturday February 22 2014, @03:14PM

    by Boxzy (742) on Saturday February 22 2014, @03:14PM (#4835) Journal

    In the same sentence? My brain hurts.

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