0 a rocket on a spacecraft or an aircraft that fires in the opposite direction to the direction in which the vehicle is travelling, in order to slow it down
Total capsule length was 10.8 ft, including a retrorocket pack strapped over the heat shield.
Just before the scheduled firing of its retrorocket, a command was sent to inflate cushioning air bags around the landing probe.
Because of weight constraints, there was no backup retrorocket engine.
Biosatellite 1 was not recovered because of the failure of a retrorocket to ignite.
White paint, gold and chrome plating, and a silvered plastic sheet encasing the retrorocket furnished thermal control.
At 250 m from the surface, the main retrorocket was turned off and the four outrigger engines were used to slow the craft.
A backup solid-fuel retrorocket was added to the top of the descent module.
The spacecraft was maneuvered into retrofire attitude and the first retrorocket fired.
