Since rockets have the potential for fire or explosive destruction, space capsules generally employ some sort of launch escape system, consisting either of a tower-mounted solid-fuel rocket to quickly carry the capsule away from the launch vehicle (employed on Mercury, Apollo, and Soyuz, the escape tower being discarded at some point after launch, at a point where an abort can be performed using the spacecraft's engines), or else ejection seats (employed on Vostok and Gemini) to carry astronauts out of the capsule and away for individual parachute landings.