Does Falcon 9's first stage use only GPS when it makes its vertical precision landing, or is it assisted also by radar or laser ranging or computer vision? If not, why not?

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    $\begingroup$ @Christoph my style is different; I usually just post the question "Does this answer your question" without the insta-close. In this case I would have mentioned the radar in the other answer and recommended that the question focus only on laser-ranging and computer vision. The whole close and open drama can usually be avoided, especially when the OP is a regular user on the site. If you close it, you block the entire community from answering about the laser ranging or computer vision part until the reopen happens, wasting time. I see no reason to pre-block answers, it's not helpful. $\endgroup$
    – uhoh
    Commented Aug 26, 2020 at 13:01
  • $\begingroup$ I assume you can cite those other questions and their answers and then narrow your question to the last two (laser ranging and/or computer vision), the sooner the better so that the insta-blocking of answers can be lifted. $\endgroup$
    – uhoh
    Commented Aug 26, 2020 at 13:12
  • $\begingroup$ @uhoh voting against reopening. I do not block anyone from putting their answers were they are most useful: on one or both of the linked questions. $\endgroup$
    – Christoph
    Commented Aug 26, 2020 at 13:57
  • $\begingroup$ @Christoph how could someone possibly know to write an answer about laser ranging or computer vision on a different question where it is not asked? Let's wait and see if LF edits the question and starts the reopen process before voting against reopening! $\endgroup$
    – uhoh
    Commented Aug 26, 2020 at 13:59
  • $\begingroup$ @uhoh GdD's comment on the other question mentioning laser ranging is a pretty solid indicator that it's obvious. There is no use in editing the question to be an even smaller subset of a different question. If someone knows how they do it he will be able to answer without being asked if they use XYZ. $\endgroup$
    – Christoph
    Commented Aug 26, 2020 at 14:04

1 Answer 1


It uses GPS and, as backup, an intertial navigation system. The two have always provided virtually identical navigation data. A SpaceX employee said that in an interview.

  • $\begingroup$ Nice answer, but including a source for your information would improve it. $\endgroup$
    – DrSheldon
    Commented Aug 26, 2020 at 12:53

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