A launch escape system (LES) or launch abort system (LAS) is a crew-safety system connected to a

space capsule A space capsule is an often-crewed spacecraft that uses a blunt-body reentry capsule to reenter the Earth's atmosphere without wings. Capsules are distinguished from other satellites primarily by the ability to survive reentry and return a payl ...

that can be used to quickly separate the capsule from its

launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload ( spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and ...

in case of an emergency requiring the abort of the launch, 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 A launch pad is an above-ground facility from which a rocket-powered missile or space vehicle is vertically launched. The term ''launch pad'' can be used to describe just the central launch platform ( mobile launcher platform), or the entir ...

, or during its ascent. Such systems are usually of two types: *A solid-fueled rocket, mounted above the capsule on a tower, which delivers a relatively large thrust for a brief period of time to send the capsule a safe distance away from the launch vehicle, at which point the capsule's parachute recovery system can be used for a safe landing on ground or water. The tower and rocket are jettisoned from the

space vehicle A space vehicle is the combination of a spacecraft and its launch vehicle which carries it into space. The earliest space vehicles were expendable launch systems, using a single or multistage rocket to carry a relatively small spacecraft in pr ...

in a normal flight at the point where it is either no longer needed, or cannot be effectively used to abort the flight. These have been used on the Mercury,

Apollo Apollo, grc, Ἀπόλλωνος, Apóllōnos, label=genitive , ; , grc-dor, Ἀπέλλων, Apéllōn, ; grc, Ἀπείλων, Apeílōn, label= Arcadocypriot Greek, ; grc-aeo, Ἄπλουν, Áploun, la, Apollō, la, Apollinis, label ...

Soyuz Soyuz is a transliteration of the Cyrillic text Союз ( Russian and Ukrainian, 'Union'). It can refer to any union, such as a trade union (''profsoyuz'') or the Union of Soviet Socialist Republics (Сою́з Сове́тских Социалис ...

, and Shenzhou capsules. *The crew are seated in seats that eject themselves (ejection seats) as used in military aircraft; each crew member returns to Earth with an individual parachute. Such systems are effective only in a limited range of altitudes and speeds. These have been used on the

Vostok Vostok refers to east in Russian but may also refer to: Spaceflight * Vostok programme, Soviet human spaceflight project * Vostok (spacecraft), a type of spacecraft built by the Soviet Union * Vostok (rocket family), family of rockets derived from ...

and

Gemini Gemini may refer to: Space * Gemini (constellation), one of the constellations of the zodiac ** Gemini in Chinese astronomy * Project Gemini, the second U.S. crewed spaceflight program * Gemini Observatory, consisting of telescopes in the Norther ...

capsules.

History

The idea of using a rocket to remove the capsule from a space vehicle was developed by

Maxime Faget Maxime Allen "Max" Faget (pronounced ''fah-ZHAY''; August 26, 1921 – October 9, 2004) was a Belizean-born American mechanical engineer. Faget was the designer of the Mercury spacecraft, and contributed to the later Gemini and Apollo spa ...

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, LES were used on American Mercury and

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 The Lockheed Propulsion Company was a division of the Lockheed Aircraft Corporation located at 1500 Crafton Avenue in the Mentone, California area northeast of Redlands, California, adjacent to the Santa Ana River, from 1961 to 1975. It developed, ...

). Apollo used a design that had many similarities to the Mercury system. LES continue to be used on the Russian

and Chinese

Shenzhou spacecraft Shenzhou (, ; see ) is a spacecraft developed and operated by China to support its crewed spaceflight program, China Manned Space Program. Its design resembles the Russian Soyuz spacecraft, but it is larger in size. The first launch was on 19 ...

. The SpaceX designed

Dragon 2 Dragon 2 is a class of partially reusable spacecraft developed and manufactured by American aerospace manufacturer SpaceX, primarily for flights to the International Space Station (ISS). SpaceX has also launched private missions such as Ins ...

uses a hypergolic liquid-fueled launch abort system integrated to the capsule and the

Boeing Starliner The Boeing CST-100 Starliner
is a class of two partially

uses abort thrusters in its service module.

ejection seat In aircraft, an ejection seat or ejector seat is a system designed to rescue the pilot or other crew of an aircraft (usually military) in an emergency. In most designs, the seat is propelled out of the aircraft by an explosive charge or rock ...

s. The European Space Agency's

Hermes Hermes (; grc-gre, wikt:Ἑρμῆς, Ἑρμῆς) is an Olympian deity in ancient Greek religion and Greek mythology, mythology. Hermes is considered the herald of the gods. He is also considered the protector of human heralds, travelle ...

and the Soviet ''Buran''-class

spaceplane A spaceplane is a vehicle that can fly and glide like an aircraft in Earth's atmosphere and maneuver like a spacecraft in outer space. To do so, spaceplanes must incorporate features of both aircraft and spacecraft. Orbital spaceplanes te ...

s would also have made use of them if they had ever flown with crews. As shown by Soyuz T-10a, a 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/

transliterate Transliteration is a type of conversion of a text from one script to another that involves swapping letters (thus ''trans-'' + '' liter-'') in predictable ways, such as Greek → , Cyrillic → , Greek → the digraph , Armenian → or L ...

d Russian ''Система Аварийного Спасения'' or ''Sistema Avariynogo Spaseniya'', meaning emergency rescue system. The Soviet Proton launcher has flown dozens of times with an escape tower, under the

Zond program Zond (russian: Зонд, lit=probe) was the name given to two distinct series of Soviet robotic spacecraft launched between 1964 and 1970. The first series, based on the 3MV planetary probe, was intended to gather information about nearby plan ...

and the TKS program. All of its flights were uncrewed. The

Space Shuttle The Space Shuttle is a retired, partially reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. Its official program ...

was fitted with ejection seats for the two pilots in the initial test 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 1986 ''Challenger'' disaster, all surviving orbiters were fitted to allow for crew evacuation through the main ingress/egress hatch (using a specially developed parachute system that could be worn over a spacesuit), although only when the Shuttle was in a controlled glide. Crew_Dragon_Pad_Abort_Test_(16814592054)

Crew_Dragon_Pad_Abort_Test_(16814592054)

The Orion spacecraft which was developed to follow the Space Shuttle program uses a Mercury and Apollo-style escape rocket system, while an alternative system, called the

Max Launch Abort System The Max Launch Abort System (MLAS) was a proposed alternative to the Maxime Faget-invented "tractor" launch escape system (LES) that was planned for use by NASA for its Orion spacecraft in the event an Ares I malfunction during launch requir ...

(MLAS), was investigated and would have used existing solid-rocket motors integrated into the bullet-shaped protective launch shroud. Under NASA's

Commercial Crew Development Development of the Commercial Crew Program began in the second round of the Commercial Crew Development (CCDev) program, which was rescoped from a technology development program for human spaceflight to a competitive development program that woul ...

(CCDev) program Blue Origin was awarded $3.7 million for development of an innovative 'pusher' LAS, it is used on the

New Shepard Crew Capsule New Shepard is a Reusable launch vehicle, fully reusable Sub-orbital spaceflight, suborbital launch vehicle developed by Blue Origin for space tourism. The vehicle is named after Alan Shepard, the first American astronaut in space. The vehicle ...

. Also under NASA's CCDev program, SpaceX was awarded $75 million for the development of their own version of a "pusher" LAS. Their

spacecraft was to use its

SuperDraco SuperDraco is a hypergolic propellant rocket engine designed and built by SpaceX. It is part of the SpaceX Draco family of rocket engines. A redundant array of eight SuperDraco engines provides fault-tolerant propulsion for use as a launch es ...

engines during a launch abort scenario. Although often referred to as a "pusher" arrangement since it lacks a tower, the Dragon 2 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 Space Launch Complex 40 (SLC-40), previously Launch Complex 40 (LC-40) is a launch pad for rockets located at the north end of Cape Canaveral Space Force Station, Florida. The launch pad was used by the United States Air Force for 55 Titan III ...

Cape Canaveral Air Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the statio ...

, on May 6, 2015. SpaceX

tested ''Tested'' is a live album by punk rock band Bad Religion. It was recorded in the USA, Canada, Germany, Estonia, Denmark, Italy and Austria, in 1996, and released in 1997. It is Bad Religion's second live album. Instead of using crowd microphon ...

the system on January 19, 2020 during ascent of the Falcon 9 rocket in Kennedy Space Center Launch Complex 39, from where it has later launched crews to the International Space Station. The second crewed spacecraft selected by NASA for its CCDEV program was

Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and p ...

CST-100 Starliner The Boeing CST-100 Starliner
is a class of two partially

, which like SpaceX's

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 Aerojet Rocketdyne is an American manufacturer of rocket, hypersonic, and electric propulsive systems for space, defense, civil and commercial applications. Headquartered in Sacramento, California, the company is owned by Aerojet Rocketdyne Hold ...

. The abort system was tested successfully during Starliner's pad abort test on November 4, 2019 at

White Sands Missile Range White Sands Missile Range (WSMR) is a United States Army military testing area and firing range located in the US state of New Mexico. The range was originally established as the White Sands Proving Ground on 9July 1945. White Sands National P ...

Orbital Sciences Corporation Orbital Sciences Corporation (commonly referred to as Orbital) was an American company specializing in the design, manufacture, and launch of small- and medium- class space and launch vehicle systems for commercial, military and other governmen ...

intends to sell the LAS it was building for the Orion spacecraft to future commercial crew vehicle providers in the wake of cancelation of the Constellation project.

Usage

ISRO Pad abort test Crew Module lifting off

During the Mercury-Redstone 1 mission on November 21, 1960, the escape system unintentionally blasted off from the Mercury spacecraft after the Redstone booster engine shut down just after ignition on the pad. The spacecraft remained attached to the booster on the ground. An accidental pad firing of a launch escape system occurred during the attempted launch of the uncrewed

Soyuz 7K-OK No.1 Soyuz 7K-OK No.1 was an uncrewed spacecraft of the Soyuz programme, originally intended to perform a rendezvous maneouvre with Kosmos 133 (Soyuz 7K-OK No.2). After the Kosmos 133 mission failed, the rocket was moved to the launch pad on 12 Dec ...

spacecraft on December 14, 1966. The vehicle's strap-on boosters did not ignite, preventing the rocket from leaving the pad. About 30 minutes later, while the vehicle was being secured, the LES engine fired. Separation charges started a fire in the rocket's third stage, leading to an explosion that killed a pad worker. During the attempted launch, the booster switched from external to internal power as it normally would do, which then activated the abort sensing system. Originally it was thought that the LES firing was triggered by a gantry arm that tilted the rocket past 7 degrees, meeting one of the defined in-flight abort conditions. Soyuz T-10-1 abort

The first usage with a crewed mission occurred during the attempt to launch

Soyuz T-10-1 Soyuz 7K-ST No.16L, sometimes known as Soyuz T-10a or Soyuz T-10-1, was an unsuccessful Soyuz mission intended to visit the Salyut 7 space station, which was occupied by the Soyuz T-9 crew. However, it never finished its launch countdown; the ...

on September 26, 1983. The rocket caught fire, just before launch, and the LES carried the crew capsule clear, seconds before the rocket exploded. The crew were subjected to an acceleration of 14 to 17 ''g'' (140 to 170 m/s²) for five seconds and were badly bruised. Reportedly, the capsule reached an altitude of and landed from the launch pad. On October 11, 2018 the crew of

Soyuz MS-10 Soyuz MS-10 was a crewed Soyuz MS spaceflight that aborted shortly after launch on 11 October 2018 due to a failure of the Soyuz-FG launch vehicle boosters. MS-10 was the 139th flight of a Soyuz spacecraft. It was intended to transport two me ...

separated from their launch vehicle after a booster rocket separation failure occurred at an altitude of 50 km during the ascent. However, at this point in the mission the LES had already been ejected and was not used to separate the crew capsule from the rest of the launch vehicle. Backup motors were utilized to separate the crew capsule resulting in the crew landing safely and uninjured approximately 19 minutes after launch. On September 12, 2022 during Blue Origin

New Shepard New Shepard is a fully reusable suborbital launch vehicle developed by Blue Origin for space tourism. The vehicle is named after Alan Shepard, the first American astronaut in space. The vehicle is capable of vertical takeoff and vertical lan ...

flight NS-23, the booster's

BE-3 The BE-3 (''Blue Engine 3'') is a LH2/ LOX rocket engine developed by Blue Origin. The engine began development in the early 2010s, and completed acceptance testing in early 2015. The engine is being used on the New Shepard suborbital rocket, ...

engine suffered a failure at about 1 minute into the flight. The launch escape system was triggered and the capsule successfully separated and landed nominally. The flight was carrying microgravity scientific payloads in the crew capsule, without crew on board.

References

External links

Launch Pad Escape System Design (Human Spaceflight)
NASA.gov

{{DEFAULTSORT:Launch Escape System Human spaceflight Spacecraft components

History

Related systems

Usage

See also

References

External links