A solid rocket on top of the Mercury spacecraft, used in an emergency escape. The rocket had a 25 200 kg thrust and was supported by a 3-m tall steel frame. An astronaut would rotate an abort handle to fire it and propel the capsule away from the launch vehicle.

On the launch pad, the rocket could blast the Mercury capsule upward for approximately 0.8 km for parachute deployment. The use of escape tower rockets was discontinued for space shuttle launches when it was decided that proper use of the rocket was too complex, and that weight taken up by the rocket could be better used for payloads. Russia used an escape tower system for Soyuz spacecraft launches.