OrbitalHub

Credits: NASA

One of the crucial requirements for a man-rated launch system is a reliable Launch Abort System (LAS). LAS is basically a top-mounted rocket connected to a crew module and it is used to separate the crew module from the rest of the launch vehicle in case of emergency.

An emergency can be anything from an explosion of the launch vehicle on the launch pad to a failed separation of the lower stage during flight.

In the case of the Orion Module, several designs were considered for the LAS: the Multiple External Service Module Abort Motor concept, the Crew Module Strap On Motors concept, and the In-Line Tandem Tractor (Tower) concept. The latter concept was incorporated in the Ares I/Orion design.

The Tandem Tractor (Tower) design of the LAS has three motors: an Attitude Control Motor (eight nozzles), a Jettison Motor (four aft nozzles), and the Abort Motor (four exposed flow nozzles). These motors will make possible the separation of the module and the control of the flight after the separation from the launch vehicle. An important component of the LAS is the Boost Protective Cover (BPC), which protects the crew module from the exhaust of the motors.

Credits: NASA

The LAS is designed to perform on the launch pad as well as during the first 300,000 feet after the launch. There are three possible scenarios for the abort procedure: on the launch pad, on the mid-altitude flight segment (up to an altitude of 150,000 feet), and on the high-altitude flight segment (from 150,000 feet to 300,000 feet, where the LAS is jettisoned on a nominal flight). Tests will have to be performed to cover these scenarios: on the launch pad as well in flight.

NASA has made available animations of the test flights planned for the LAS. One is the animation of the Orion Module LAS pad abort flight test. The second presents the Orion Module LAS ascent abort flight test.

Credits: NASA

Currently, the Launch Abort System of the Orion Module is under development.

The first full-scale test fire of the motor that powers the LAS was completed on November 20, 2008. This was the first time a LAS test has been conducted since the 1960s, when the LAS for the Apollo Program was tested.