NASA will conduct the Ascent Abort -2 (AA-2) test for the Orion capsule tomorrow morning at Cape Canaveral Air Force Station, FL. The three-minute test is scheduled for 7:00 am ET, although the launch window extends until 11:00 am ET. The test is to demonstrate the ability to separate the Orion capsule from its rocket in case of an emergency after launch. If all goes as planned, the next flight of this Launch Abort System will on the first SLS/Orion mission to carry a crew.

Lockheed Martin is the prime contractor for NASA’s Orion capsule, which has been in development since 2006. Orion was originally designed for President George W. Bush’s Constellation program to return astronauts to the Moon by 2020. It was retained by NASA after Constellation was cancelled by President Barack Obama in 2010 and Congress subsequently directed NASA to build a new big rocket, the Space Launch System, and a “Multi-Purpose Crew Vehicle” (MPCV) to take astronauts beyond low Earth orbit. Orion was selected to fulfill the MPCV mandate.

The SLS/Orion configuration is similar to that used in the Mercury, Gemini and Apollo programs where the crew capsule is on top on the rocket. A separate rocket motor thus can be mounted on top of the capsule to pull (or push) it away from the rocket in an emergency. The space shuttle orbiter was mounted on the side of its booster rockets and did not have this type of escape system.

The value of a launch abort system was demonstrated last October during the Soyuz MS-10 launch when the first stage of a Russian Soyuz rocket did not separate correctly two minutes after liftoff and caused a catastrophic launch failure. The Soyuz capsule, carrying Russian cosmonaut Aleksey Ovchinin and NASA astronaut Nick Hague, automatically separated from the rocket and landed safely downrange. The two men were not injured and, in fact, got a second chance to fly in March aboard another Soyuz rocket and are now aboard the International Space Station (ISS).

All three of NASA’s new crew spacecraft — Orion and the two commercial crew systems being built by SpaceX (Crew Dragon) and Boeing (CST-100 Starliner) — have launch abort systems.

During a press conference today, NASA astronaut Randy Bresnik said that what NASA learned from the Soyuz MS-10 experience was that astronauts always need to be prepared for a launch abort even though it is highly unlikely. It had been 35 years since Russia’s abort system was needed (the 1983 Soyuz T-10 mission.)

The test tomorrow will use a mockup of an Orion, not an actual vehicle. It has the same dimensions and mass as Orion, but is not outfitted with other systems. It does not even have parachutes. At today’s press conference, AA-2 test conductor Jenny Devolites said the test capsule will hit the ocean at 300 miles per hour and is not expected to stay intact. It also is weighted to help ensure it sinks. That will happen about 7.5 miles offshore.

A NASA video shows what will happen during the brief test, which will be launched with an SR118 motor from a Peacekeeper missile modified by Northrop Grumman.

As seen about half-way through the video, the motor fires to “reorient” the vehicle so that in an actual emergency the Orion heat shield would be pointing in the correct direction. Bresnik was asked what that “swing around” maneuver would feel like for the crew. He said they would experience about 7 gs (7 times the pull of gravity), but it is short duration and they train for it. He compared it to feeling like 1.5 or 2 elephants are standing on one’s chest.

The test is in preparation for flights of SLS/Orion to a Gateway in lunar orbit where crews will transfer to other spacecraft to take them down to the surface. On March 26, Vice President Pence directed NASA to land the next man and the first woman at the South Pole of the Moon by 2024.

The first SLS/Orion flight, Artemis-1, is an uncrewed test launch expected to fly in late 2020 or early 2021. The first launch of Orion with a crew is Artemis-2, which NASA hopes to launch in 2022. That will be the next mission to have a launch abort system like the one being tested tomorrow. The current plan is that Artemis-3 will be the 2024 mission that gets astronauts back on the lunar surface.

The weather is forecast 80 percent “go” for tomorrow. NASA TV coverage begins at 6:40 am ET.