Launch escape system

A launch escape system (LES) or launch abort system (LAS) is a crew safety system connected to a space capsule, used to quickly separate the capsule from its launch vehicle rocket in case of a launch abort emergency, such as an impending explosion. The LES is typically controlled by a combination of automatic rocket failure detection, and a manual activation for the crew commander's use. The LES may be used while the launch vehicle is still on the launch pad, or during its ascent. Such systems are usually of two types: A launch escape system (LES) or launch abort system (LAS) is a crew safety system connected to a space capsule, used to quickly separate the capsule from its launch vehicle rocket in case of a launch abort emergency, such as an impending explosion. The LES is typically controlled by a combination of automatic rocket failure detection, and a manual activation for the crew commander's use. The LES may be used while the launch vehicle is still on the launch pad, or during its ascent. Such systems are usually of two types: The idea of using a rocket to remove the capsule from a space vehicle was developed by Maxime Faget in 1958. The system, using the tower on the top of the space capsule to house rockets, was first used on a test of the Project Mercury capsule in March 1959.Historically, LESes were used on American Mercury and Apollo spacecraft. Both designs used a solid-fuel rocket motor. The Mercury LES was built by the Grand Central Rocket Company in Redlands, California (which later became the Lockheed Propulsion Company). Apollo used a design that had many similarities to the Mercury system. Launch Escape Systems continue to be used on the Russian Soyuz and Chinese Shenzhou programme spacecraft. The SpaceX-designed Dragon V2 uses a hypergolic liquid-fueled launch abort system integrated to the capsule to minimize spacecraft costs. The Soviet Vostok and American Gemini spacecraft both made use of ejection seats. The European Space Agency's Hermes and the Soviet Buran-class spaceplanes would also have made use of them if they had ever flown with crews. As shown by Soyuz T-10a, an LES must be able to carry a crew compartment from the launch pad to a height sufficient for its parachutes to open. Consequently, they must make use of large, powerful (and heavy) solid rockets. The Soyuz launch escape system is called CAC or SAS, from the Russian/transliterated Russian Система Аварийного Спасения or Sistema Avariynogo Spaseniya, meaning emergency rescue system. The Space Shuttle was fitted with ejection seats for the two pilots in the initial 'shakedown' flights, but these were removed once the vehicle was deemed operational and carried additional crew members, which could not be provided with escape hatches. Following the Space Shuttle Challenger disaster, all surviving orbiters were fitted to allow for crew evacuation through the main ingress/egress hatch, although only when the Shuttle was in a controlled glide, as the crew would have had to reach the exit from their seats and jump out. The Orion Multi-Purpose Crew Vehicle being developed to follow the shuttle program will use a Mercury and Apollo-style escape rocket system, while an alternative system, called the Max Launch Abort System (MLAS), has been floated to use existing solid-rocket motors integrated into the bullet-shaped protective launch shroud. Under NASA's Commercial Crew Development (CCDev) program Blue Origin has been awarded $3.7 million for development of an innovative 'pusher' LAS. Also under NASA's CCDev program, SpaceX was awarded $75 million for the development of their own version of a 'pusher' LAS. Its Dragon V2 spacecraft will use its SuperDraco engines during a launch abort scenario. Although often referred to as a 'pusher' arrangement since it lacks a tower, the Dragon V2 LAS removes both the capsule and its trunk together from the launch vehicle. The system is designed to abort with the Super Draco engines at the top of the abort stack as occurs with a more traditional tractor LAS. The concept was first tested in a Pad Abort test conducted at SLC-40, Cape Canaveral Air Force Station, on May 6, 2015. SpaceX will next test the system during ascent of the Falcon 9 rocket in Kennedy Space Center Launch Complex 39 from where it plans to launch crews to the International Space Station. The second crewed spacecraft selected by NASA for its CCDEV program was Boeing's CST-100 Starliner, which like SpaceX's Dragon 2 spacecraft, will use a 'pusher' launch escape system, consisting of four launch abort engines mounted on the service module that can propel the spacecraft away from its Atlas 5 launch vehicle in the event of an emergency on the pad or during ascent. The engines, which use hypergolic propellants and generate 40,000 pounds-force of thrust each, are provided by Aerojet Rocketdyne. Orbital Sciences Corporation intends to sell the LAS it was building for the Orion spacecraft to future commercial crew vehicle providers in the wake of cancellation of the Constellation project.