News for hackers. Stuff that matters.

A comment on SpaceX: “Close, but no cigar. This time”. Parent comment

Re:SpaceX: “Close, but no cigar. This time” by mitchty on Friday January 16, 2015 @12:49PM (#8900346)
Was probably the engine gimbaling and thrusting up to attempt to correct but was just unable to due to the fins not being around the whole descent.
[ Parent | on HN ]
Re:SpaceX: “Close, but no cigar. This time” by 0x5f3759df-i on Friday January 16, 2015 @01:23PM (#8900591)
Not only were the fins unable to move, the position they were stuck in was a very unhelpful position.
[ Parent | on HN ]
Re:SpaceX: “Close, but no cigar. This time” by Sammi on Friday January 16, 2015 @02:35PM (#8901118)
Yes, and could speculate that the main engine fired 'wrongly' because the control code didn't take into account that the fins were locked.
[ Parent | on HN ]
Re:SpaceX: “Close, but no cigar. This time” by Florin_Andrei on Friday January 16, 2015 @02:43PM (#8901175)
Hm, if I was the guy designing the control loop on that thing (not gonna happen in real world, but bear with me), I would definitely take into account the fins position - the real position, not the one I want them to be in.

Not that it would have helped anyway in this case.

[ Parent | on HN ]
Re:SpaceX: “Close, but no cigar. This time” by Symmetry on Friday January 16, 2015 @05:43PM (#8902234)
I suspect that the code takes the fin's starting position into account in each planning cycle but also assumes that the fin will move as directed in the future.
[ Parent | on HN ]
Re:SpaceX: “Close, but no cigar. This time” by Florin_Andrei on Friday January 16, 2015 @09:16PM (#8903070)
No rotary encoders on those things?
[ Parent | on HN ]