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Longer Video Shows How Incredibly Close Falcon Stage Came To Successful Landing
Bruce Perens writes In the video here, the Falcon 9 first stage is shown landing with a tilt, and then a thruster keeps the rocket vertical on the barge for a few seconds before it quits, followed by Kabooom with obvious significant damage to the barge. It looks like this attempt was incredibly close to success. Given fixes, a successful first-stage recovery seems likely.
The full tweet was as follows:
@elonmusk: @ID_AA_Carmack Looks like the issue was stiction in the biprop throttle valve, resulting in control system phase lag. Should be easy to fix.
Certainly looked that way to me. On the last oscillation before touchdown, with the tail end moving towards the left, the thrusters keep pointing the same way as the rocket goes through vertical and only change direction a little bit afterwards. This increased the amplitude of the oscillation rather than decreasing it. The thrusters should have changed direction before passing through vertical, not afterwards. I can't imagine them getting this wrong in software, it's basic dynamic stability 101, so a sticky valve seems likely.
The rocket ended up landing almost perfectly vertical, but still rotating so the base was traveling sideways over the landing pad. No way they could stay upright like that.