# What's the name of this maneuver for unlimited delta-v?

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?

• What you're talking about sounds a lot like an interstellar solar sail. Is that it, or are you using a conventional propulsion method? – HDE 226868 Aug 26 '14 at 20:10
• Well... it could be a solar sail. The propulsion method is irrelevant. What matters is that delta-v is unlimited or practically unlimited. – Pedro Werneck Aug 26 '14 at 20:48
• In that case, @RussellBorogove's answer is definitely the right one. Good question. – HDE 226868 Aug 26 '14 at 20:49
• Imagine the constant acceleration to be 1g. No more worries about artificial gravity! – SF. Aug 28 '14 at 10:02
• @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. – Kevin Kostlan Jul 27 '20 at 16:57

## 1 Answer

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

• That's it! That name is hard to remember. Thanks. – Pedro Werneck Aug 26 '14 at 20:47
• 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. – Keith Thompson Aug 26 '14 at 21:07
• See: mathworld.wolfram.com/BrachistochroneProblem.html for another origin for the weird word... – DJohnM Aug 27 '14 at 17:31
• Heinlein called it a Skew Flip Turnover: en.wikipedia.org/wiki/Skew_flip_turnover – sneak Aug 29 '14 at 1:46