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Video: Dragon 2 Propulsive Hover Test

Discussion in 'SpaceX' started by doug, Jan 21, 2016.

  1. doug

    doug Administrator / Head Moderator

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    #1 doug, Jan 21, 2016
    Last edited by a moderator: Mar 13, 2016
  2. Grendal

    Grendal Active Member

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    Unbelievably cool. I'm just wondering how much fuel will be needed for a propulsive landing? This is only a 5 second burn. You'd need a whole lot more than that to pull off a landing, I'd think. It looks like they've got this ship balanced well with all 8 engines firing. That cannot be easy to do.
     
  3. Vger

    Vger Active Member

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    I have wondered about the fuel issue also. Obviously they know what they are doing, but it is amazing to me that such a tiny craft can be so self-sufficient. We have sure come a long way from the days of Apollo! Orion seems clunky by comparison.
     
  4. Grendal

    Grendal Active Member

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    I just re-watched the Dragon 2 animation. The landing they portray is at least 30 seconds of burn time. It seems that about 25 seconds of it is a light burn followed by an intense burn right before landing.

    I know we won't see a landing on the next abort test which will happen sometime this year. That burn will be for the capsule to escape the booster. I'm sure the landing will be with parachutes like the last abort test.

    Sadly, I can't see any easy way to combine a propulsive Dragon landing with an actual normal flight like they can with the booster recovery. The propulsive landing testing will all need to be on SpaceX's dime. However, this is a good excuse to reuse an old booster which will save some money. In fact, it would be great if they reused the same booster over and over to get a good insight on the reusability of one booster.

    Maybe they can convince NASA to let them use Dragon 2 for a few resupply missions and take the chance on a propulsive landing with the return cargo. The cargo has a lot more weight than a bunch of astronauts, I think.
     
  5. Doug_G

    Doug_G Lead Moderator

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    It's all about Specific impulse - crudely, a measure of how long a rocket can hover. Rockets can't do that very long because they have to carry their fuel.

    The big Falcon 9 can hover for a mere 282 seconds (in atmosphere). The Dragon will be much shorter. The Wikipedia page lists a "burn time" of 25 seconds, so it's something on that order.

    Now you know why rocket jetpacks never took off...
     
  6. ecarfan

    ecarfan Well-Known Member

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    That is so awesome. I love it. That's the way spacecraft should land. Parachutes and slamming into the ocean is so last century.
     

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