An escape tower is a safety system for orbital launch vehicles. It consists of an array of rockets atop a tower mounted on the crew capsule, which is usually located at the tip of traditional rocket configurations for space missions. Its purpose is to quickly separate just the crew capsule from the rest of the rocket in case of emergency during launch procedures. It consists of small but powerful single stage rockets that produce very large amounts of thrust for only a second or two that are intended to pull the crew capsule clear of potential explosions or fires that can occur during catastrophic failures in rocket launches.
The first system of this type was developed for the Mercury spacecraft of the American space program in the late 1950s by Mercury space capsule designer, Max Faget. He patented his design under the name "Aerial Capsule Emergency Separation Device" and NASA, the organization responsible for the American space program, called it the Mercury Escape Tower. Similar systems were later adapted to later spacecraft series, such as the Apollo series, and by the Russians for their Soyuz spacecraft.
Mercury capsules, the first spacecraft to use an escape tower, were outfitted with the device, which resembled an oil derrick topped with a group of small but very powerful rockets that were angled to fire in such a way that the exhaust did not directly come into contact with the tower or the capsule. They were arranged to quickly carry the crew capsule upwards and laterally away from the rocket in order to keep the crew from harm in the case of any dangerous event during launch, such as a catastrophic fire, explosion, or launch failure. The escape tower was also outfitted with parachutes to bring the crew capsule safely to earth after deployment.
The rockets on an escape tower were very small, but very powerful, delivering a huge amount of thrust for a very short period. The intent behind this design is to accelerate the escape capsule very quickly to get it away from any potential danger in the shortest time possible. By providing a very large amount of thrust the capsule can be blasted upwards and away from the main launch vehicle in a matter of seconds.
The only recorded use of an escape tower was on a Soyuz rocket, which resulted in the lives of two Soviet cosmonauts being saved. Many years later, the cosmonauts were able to personally thank Max Faget for inventing the device that saved their lives. Today, NASA is developing a system with a similar purpose for their next generation of manned spacecraft, the Orion. It is named after the inventor of the original escape tower, and is called the Max Launch Abort System (MLAS).