retrorocket
- n a small rocket engine on a larger rocket or spacecraft that is fired to slow or alter its course
- Then the retrorocket is jettisoned.
- A sudden increase in frequency followed by fading of the signal led Lovell to believe that a retrorocket had been fired, slowing Luna down.
- The tardy retrorocket firing that probably made the difference between success and failure, Barringer decided, could have been caused by an altimeter error of as little as 30 ft .