In SpaceX's successful landing on the barge today, April 8th, we see there is almost no room for error, at least from the video:

still of Falcon Stage 1 on OCISLU

Note that it appears that the width of the drone ship is only about twice the length of the square formed by the landing legs. What is the maximum permissible error to achieve the landing? In particular, if it was diagonal, there would be even less room, it seems there is only an error margin at most of the landing leg spread, but I'm curious also as to if that is an issue.

  • $\begingroup$ With this hi def video, it obviously bounced after the landing. youtube.com/watch?v=sYmQQn_ZSys Looks to me like it bounced sideway for at least a meter or two. $\endgroup$ – hshib Apr 9 '16 at 3:13
  • $\begingroup$ Damn, you spoilered me :( $\endgroup$ – Roman Reiner Apr 9 '16 at 5:06
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    $\begingroup$ Watch their landing attempts. It's obvious that from the start they had the ability to hit point X nailed, the hard part has been keeping it pointed in the right direction. $\endgroup$ – Loren Pechtel Apr 9 '16 at 18:09

The landing platform of the upper deck of the initial Just Read the Instructions (JRtI) vessel was 52 m × 91 m (170 ft × 300 ft) while the span of the Falcon 9 landing legs is 18 m (60 ft). The other barges used by SpaceX have similar dimensions.
So in the most constrained direction, they can land (52/2 - 18/2) = 17 m off-center before one of the legs goes over the edge.


According to this article, the total error budget is 30 m to have an acceptable landing. So that means at most, 15m error from dead center is acceptable to land perfectly, and that 3 rockets couldn't fit on the barge at the same time, side by side.


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