# Skew flip turnover

A skew flip turnover is a maneuver in which an aircraft or spacecraft accelerates to a certain point, flips over (skew flip) and begins to accelerate in the opposite direction. Weaker spacecraft will accelerate up to a certain velocity, coast for a while, then decelerate to rest.

If the desired acceleration of the spacecraft is known (generally one g or 9.81 m/s²) and the transit time is to be calculated, the equation is

$T = 2 \sqrt{D \over A}$

where

T = time (seconds)
D = distance (m)
A = acceleration (m/s2)
1 g = 9.81 m/s²

The skew flip turnover was described in Robert A. Heinlein's book Have Space Suit—Will Travel.