OrbitalHub

Wikipedia dicit:

A launch escape system (LES) or launch abort system (LAS) is a crew-safety system connected to a space capsule that can be used to quickly separate the capsule from its launch vehicle 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, or during its ascent. Such systems are usually of two types: solid-fuelled rocket or ejection seats.

A solid-fuelled 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 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, Soyuz, 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 and Gemini capsules.

Credit: NASA’s Ames Research Center

NASA dicit:

Engineers at Northrop Grumman’s facility in Elkton, Maryland successfully conducted the third and final test of the attitude control motor (ACM) that provides steering for the Launch Abort System (LAS) on NASA’s Orion spacecraft, qualifying the motor for Artemis II, Orion’s first mission with astronauts. The LAS, consisting of three solid rocket motors, is designed to carry crew to safety in the event of an emergency during launch or ascent atop the agency’s Space Launch System rocket.

During the 30-second test, eight high pressure valves directed more than 7,000 pounds of thrust in multiple directions while firing at freezing conditions. All three motors on the LAS will be qualified for crewed flights ahead of Artemis II, another step that brings NASA closer to sending the first woman and next man to the Moon by 2024.

Video credit: NASA Johnson

NASA dicit:

A fully functional Launch Abort System (LAS) with a test version of the Orion spacecraft attached, launches on NASA’s Ascent Abort-2 (AA-2) atop a Northrop Grumman provided booster on July 2, 2019, at 7 a.m. EDT, from Launch Pad 46 at Cape Canaveral Air Force Station in Florida. During AA-2, the booster will send the LAS and Orion to an altitude of 31,000 feet at Mach 1.15 (more than 1,000 mph). The flight test will prove that the abort system can pull crew to safety in the unlikely event of an emergency during ascent.

Video Credit: NASA’s Kennedy Space Flight Center

Northrop Grumman dicit:

“We completed the second qualification test for the launch abort motor for NASA’s Orion Spacecraft. The motor fired for 5 seconds with a force of just under 370,000 pounds and will be used to pull the crewed capsule away from NASA’s Space Launch System in the event of an emergency on the launch pad or during ascent. The next major milestone for the motor will be the Ascent Abort-2 Flight Test (AA-2) that will take place in 2019.”

Video Credit: Northrop Grumman

NASA dixit:

“In a test targeted for April 2019 known as Ascent Abort-2, NASA will verify the Orion spacecraft’s launch abort system, a tower on top of the crew module, can steer the capsule and astronauts inside it to safety in the event of an issue with the Space Launch System rocket when the spacecraft is under the highest aerodynamic loads it will experience during ascent for deep-space missions. The test is quick, fast and high, lasting less than three minutes with the test crew module reaching an average speed of Mach 1.5, roughly 1020 miles per hour, at approximately 32,000 feet in altitude.”

Video credit: NASA Johnson

SpaceX dixit:

“This will be the first flight test of SpaceX’s revolutionary new launch abort system, and the odds of encountering delays or issues are high. Fortunately the test doesn’t need to be perfect to be valuable—our primary objective is to capture as much data as possible as the data captured here will be key in preparing Crew Dragon for its first human missions in 2017.

A Pad Abort Test is a trial run for a spacecraft’s launch abort system (sometimes called a launch escape system). This system is designed to quickly get the crew and spacecraft away from the rocket in the event of a potential failure. It is similar to an ejection seat for a fighter pilot, but instead of ejecting the pilot out of the spacecraft, the entire spacecraft is “ejected” away from the launch vehicle.

Previous launch abort systems have been powered by a rocket tower mounted on top of the spacecraft. During an emergency, the tower would ignite and essentially pull the spacecraft to safety. This works well while the spacecraft is on the launch pad and for a few minutes into ascent, but once the vehicle reaches a certain altitude, the system is no longer useful and must be discarded. SpaceX’s launch abort system, however, is integrated directly into the spacecraft. This means Crew Dragon will have launch escape capability from the launch pad all the way to orbit.

Instead of a separate rocket tower mounted on top of the spacecraft, SpaceX’s launch abort system leverages eight SuperDraco rocket engines built into the walls of the Crew Dragon spacecraft. The SuperDracos are capable of producing 120,000 lbs of axial thrust in under a second, which results in transporting the Crew Dragon spacecraft nearly 100 meters (328 ft) in 2 seconds, and more than half a kilometer (1/3 mi) in just over 5 seconds.”

Credit: SpaceX