A key safety system on NASA's Orion spacecraft — one that could save lives during launch — will undergo a major test sooner than expected, the agency announced last week.

The Orion spacecraft is similar to the Apollo-era crafts that carried astronauts to the moon and back. It is being designed to launch atop NASA's Space Launch Systems (SLS) rocket, which is also under development. Part of the Orion-SLS system is the launch abort system (LAS), would consists of a small motor that can fire and jettison the human craft away from the rocket in an emergency during launch.

The "full-stress" test of the LAS will now take place in April 2019, the agency announced Nov. 9. The spacecraft will launch atop a Peacekeeper rocket that is being modified by Orbital ATK into an Abort Test Booster for the test. (The SLS will still be in development or test phases at that point.) The LAS will travel to an altitude of 32,000 feet (9,750 meters) at Mach 1.3, or about 1,000 miles per hour (1,600 km/h). At that point, the LAS motor will fire and send the Orion vehicle away from the rocket. [Orion Explained: NASA's Multi-Purpose Crew Vehicle (Infographic)]

"This will be the only time we test a fully active launch abort system during ascent before we fly crew, so verifying that it works as predicted, in the event of an emergency, is a critical step before we put astronauts on board," Don Reed, manager of the Orion Program’s Flight Test Management Office at NASA's Johnson Space Center in Houston, said in the statement. "No matter what approach you take, having to move a 22,000-pound spacecraft away quickly from a catastrophic event, like a potential rocket failure, is extremely challenging."

The LAS consists of three motors — the launch abort, attitude control and jettison motors. If the launch goes smoothly and the LAS is not necessary, the jettison motor would fire at a high altitude and separate the LAS from Orion, leaving the vehicle free to continue its mission.

In the statement, NASA said it is moving up the date of the test to "provide engineers with critical abort test data sooner to help validate computer models of the spacecraft's LAS performance and system functions."

The Orion LAS has been tested previously, but only while the spacecraft was sitting on a launch pad, not atop a rocket in flight.

The April 2019 test will not be a full simulation of what would happen in a crewed flight emergency. In the event that the LAS is activated while a crew is onboard Orion, the capsule would jettison away from the rocket, then descend to Earth with the help of its parachute system, according to the statement. In the April 2019 test, the spacecraft will not deploy the landing parachutes. In addition, the Orion capsule that will be used in the test will not be equipped with additional thrusters (part of a "reaction control system") that would help the actual Orion spacecraft make its descent and splash down if the LAS were deployed. [Exploration Mission 1: A Step-by-Step Return to the Moon in Pictures]

Orion has made one test flight around the Earth, but that vehicle was not qualified to carry humans to space. The craft will also not carry crew members on the first integrated flight of Orion and the SLS rocket (Exploration Mission 1, or EM-1) and the LAS will not be fully operational on that flight, according to the statement from NASA.. The agency is aiming for an EM-1 launch date in December 2019, although a recent report suggests it could easily be pushed back to June 2020.

The agency also released a video this week about work being done to ensure that crew members could be evacuated from Orion while the rocket is still on the launchpad. The video shows a recent test in which four astronauts participated in a run-through of those evacuation procedures.

"If there's any sort of emergency called, we want to make sure that the flight crew and the ground crew can get safely out of the capsule and away from the stack," Jennifer Boyer, the Orion human engineering system manager, said in the video. "Orion is supposed to take these crew to Mars, so we need to make sure that we have a design that supports operations from the launch pad all the way through deep space. And it's important that we keep the crew safe so that they can return home to their families."

Correction: This story incorrectly stated that the LAS would launch atop an Atlas V rocket for the 2019 test; it will launch atop Abort Test Booster, which is a Peacekeeper that is being modified by Orbital ATK for the test.

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