Let's say you have magical unlimited delta-v, but very low thrust-to-weight ratio. You could travel by accelerating constantly for half the trip, then braking for the other half, until your arrival.

I remember someone describing this maneuver and using a name, but I can't remember the name or find any references. What is it called?

  • $\begingroup$ What you're talking about sounds a lot like an interstellar solar sail. Is that it, or are you using a conventional propulsion method? $\endgroup$
    – HDE 226868
    Aug 26, 2014 at 20:10
  • $\begingroup$ Well... it could be a solar sail. The propulsion method is irrelevant. What matters is that delta-v is unlimited or practically unlimited. $\endgroup$ Aug 26, 2014 at 20:48
  • $\begingroup$ In that case, @RussellBorogove's answer is definitely the right one. Good question. $\endgroup$
    – HDE 226868
    Aug 26, 2014 at 20:49
  • 1
    $\begingroup$ Imagine the constant acceleration to be 1g. No more worries about artificial gravity! $\endgroup$
    – SF.
    Aug 28, 2014 at 10:02
  • $\begingroup$ @SF: a 1g constant acceleration and almost endless delta-v sounds wonderful, until you realize that the antimatter fuel needed for this means basically everyone can own a nuke. $\endgroup$ Jul 27, 2020 at 16:57

1 Answer 1


That's a brachistochrone or constant-acceleration trajectory; Heinlein was fond of it and called the turnover the "skew-flip maneuver".

  • $\begingroup$ That's it! That name is hard to remember. Thanks. $\endgroup$ Aug 26, 2014 at 20:47
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    $\begingroup$ If I recall correctly, the "skew-flip maneuver" was a curved path designed to maintain a constant 1-G on-board acceleration during turnover. A simpler alternative would be to turn off the engines, rotate the ship, and restart the engines. Reasons for the skew-flip might include the comfort of the passengers and concern about being able to restart the engines. $\endgroup$ Aug 26, 2014 at 21:07
  • $\begingroup$ See: mathworld.wolfram.com/BrachistochroneProblem.html for another origin for the weird word... $\endgroup$
    – DJohnM
    Aug 27, 2014 at 17:31
  • $\begingroup$ Heinlein called it a Skew Flip Turnover: en.wikipedia.org/wiki/Skew_flip_turnover $\endgroup$
    – sneak
    Aug 29, 2014 at 1:46

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