Some details on the SpaceX’s attempt to land its Falcon 9 first stage

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This SpaceX press release gives some good info on the difficulty they face getting the first stage on Tuesday’s Dragon launch to land successfully on its floating sea platform:

To complicate matters further, the landing site is limited in size and not entirely stationary. The autonomous spaceport drone ship is 300 by 100 feet, with wings that extend its width to 170 feet. While that may sound huge at first, to a Falcon 9 first stage coming from space, it seems very small. The legspan of the Falcon 9 first stage is about 70 feet and while the ship is equipped with powerful thrusters to help it stay in place, it is not actually anchored, so finding the bullseye becomes particularly tricky. During previous attempts, we could only expect a landing accuracy of within 10km. For this attempt, we’re targeting a landing accuracy of within 10 meters.

They are going to try however, and they will be filming their attempt all the way. Stay tuned for some very interesting footage.



  • mpthompson

    If on this first attempt the F9 gets within a few hundred meters of the barge, I would consider that a success. To my knowledge the small steering wings added to guide the F9 down haven’t be used on such a flight. They’ve only been tested on the short grasshopper test flights which in no way simulates the full flight down from near orbital heights and velocities. I can’t imagine that some tweaking still remains to properly guide the F9 down to a 10 meter target in the middle of the ocean.

    If a soft landing on the barge is indeed achieved on the first attempt, it will be a VERY impressive achievement. They have to have some rather spectacular simulation software for the guidance control algorithms to be coded against.

  • D K Rögnvald Williams

    Can we assume the purpose of landing on a barge is safety for ground-dwellers, ease of returning the rocket to its spaceport, or both?

  • mpthompson

    The barge is the next incremental step towards re-usability with considerations towards both safety for those on the land while demonstrating that 14 story object traveling at the speed of a rifle bullet can be guided down backwards with adequate precision. However, I believe the ultimate goal for the F9R is flyback of the first stage booster all the way to the launch site or somewhere else on dry land along the coast. The barge is just a stepping stone.

  • Edward

    I agree with mpthompson, that the preferred method is to return directly to the launchsite/spaceport, but that requires extra fuel to turn around and then to stop the rocket’s “forward” motion again at the spaceport. However, the rocket would be immediately available for refurbishment, with no transportation-time delay spent on the barge.

    The barge would still be available for launches in which the payload weight does not leave enough fuel in the first stage for it to return to the spaceport or in which the spaceport does not have a “landing pad.”

    Landing on a rolling, rocking, pitching barge with who-knows-what kind of winds and gusts is quite a test of the system. Even after it lands on the barge, the rocket has to be prevented from tipping over – or blowing over – the side.

    To paraphrase a song, if you can land it there, you can land it anywhere.

  • D K Rögnvald Williams

    Good one.

  • t-dub

    Live coverage on their YouTube channel and the NASA feed is over at Spaceflight Now is starting as I type.

  • pzatchok

    The steering panels are the same design as ones used on new free fall guided bombs and hypersonic missiles.

    They are pretty good. They just needed to be scaled up to match the mass of the rocket.

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