NASA has carried out another dramatic test of the emergency escape system for its upcoming Space Launch System (SLS). The Launch Abort System (LAS) sits at the very top of the gigantic rocket, and is tasked with forcefully pulling the crew out of harm’s way in the event of a life-threatening mission failure.
Launch Abort Systems have been a standard, but very necessary, inclusion of every human rated launcher ever since the Mercury Program – from the titanic Saturn V used to explore Earth’s Moon in the 1960s and 70s, to the Russian-built Soyuz launchers that streak through the skies above Baikonur Cosmodrome today.
The Space Launch System’s LAS can be divided into two parts. The first element is the fairing assembly, which is made up of a lightweight shell that covers the capsule during ascent. The fairing protects the crew module from the heat, wind and acoustic stresses that it would otherwise have to endure while making its way from the launchpad to space, or in a potentially life-threatening situation during an abort scenario.
The second component is the launch abort tower, which sits atop the fairing assembly. The tower is the very tip of the rocket, and harbors three abort motors, as well as jettison and attitude control motors. In an emergency on the launch pad or during flight with the rocket’s first stage, the abort motors would fire, pulling the crew away from the main body of the SLS with an impressive 400,000 pounds of thrust.
The LAS would then re-orientate using the attitude thrusters, before the jettison motor fires up, releasing the capsule from its shroud and allowing its parachutes to deploy.
However, no parachutes were used in today’s stress test. This is in part because they have already been extensively tested, having gone through 49 drop tests and two launch-to-landing tests and also because NASA has chosen to use a 22,000 lb (9,980 kg) dummy spacecraft, rather than a real Orion for the trial run.
During today’s test, the LAS and dummy Orion were hefted into the air by the converted first stage of a modified US Peacekeeper missile, provided by Northrop Grumman. The booster lifted off at 7 am EDT from Complex 46 at Cape Canaveral Air Force Station in Florida.
Upon reaching roughly 31,000 ft (9,450 m) and traveling at over 800 mph (1,287 km/h), the LAS system fired, tearing the capsule away from its launcher. The abort system was then able to successfully re-orientate and release the faux Orion.
While tumbling towards the Earth, the capsule jettisoned 12 data recorders fitted with GPS receivers before smashing into the Atlantic Ocean at around 300 mph (483 km/h). The Orion test craft had been designed to break up on impact and sink to form a reef.
All of the data recorders have now been retrieved by boat.
The entire test lasted a little over three minutes, and in a NASA briefing following the event, launch director Don Reed commented that if a crew had been aboard, they would have survived, with the addition of parachutes of course.
Today represented the second and last time that the LAS will be tested prior to the maiden journey of the Space Launch System during Artemis 1, which is expected to take place next year. According to NASA, the abort tower will not be fully active during the mission, as there will be no astronauts inside the Orion crew capsule.