A

David

Darling

thrust equalizer

A thrust equalizer is a safety device that prevents motion of a spacecraft if its solid-fuel rocket motor ignites accidentally. The device is usually a vent at the top of the thrust chamber that is left open until launch time. If the fuel ignites accidentally before launch, the gases of combustion will blow out from both the top and bottom of the motor, thus equalizing thrust on both sides and preventing the spacecraft from launching prematurely.