Evrim Yazgin
Cosmos science journalist
All eyes will be on Cape Canaveral, Florida tonight as NASA’s latest moon project, Artemis 1 prepares to launch.
It’s phase one of three in NASA’s long-awaited bid to return to the moon. The mission aims to establish a long-term human base on Earth’s satellite by the end of the decade.
Initially it’s a series of tests, or proof of concept, which will stretch science and human endeavour.
Artemis 1 is uncrewed and will, among other things, test the Orion spacecraft and ‘Space Launch System’ rocket. This means certain safety measures to protect future crewed launches are in place in Artemis 1.
It is an unfortunate fact that rockets do sometimes fail either while launching, or soon after. I mean, it is literally rocket science, so there are a lot of complexities and things that can and do go wrong.
So, what have engineers put in place to protect the crew?
NASA has implemented the Launch Abort System (LAS). The LAS is designed to protect the astronauts in the case of a failed launch by pulling the crew module away from the rocket.
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LAS itself weighs over 7,000 kilograms and, according to NASA, “it can activate within milliseconds to pull the vehicle to safety and position the module for a safe landing.”
It contains three solid propellant rocket motors made by Northrop Grumman. The motors are the abort motor, an attitude control motor and a jettison motor.
The abort motor can produce nearly two million newtons of thrust force to quickly pull the crew module away from any danger emerging from a failed launch or ascent. According to NASA, this thrust can lift 26 elephants off the ground.
The attitude control motor would be used to steer the crew module in any direction from inside the vehicle.
And the jettison motor will pull the LAS away from the crew module, allowing Orion’s parachutes to deploy so the craft can land safely in the ocean. NASA says it can pull the LAS away from the crew module to a height of around 100 kilometres.
The abort motor is capable of reaching 800 kilometres per hour within two seconds! But, doesn’t that make this safety device dangerous? Such acceleration would produce a G-force (the force felt by an object due to its locomotion) of over 11g.
A normal human body can withstand G-forces up to 9g. But astronauts are built (well, trained) differently. With conditioning, they can withstand 10-15g. During re-entry in 1963, astronauts aboard the Mercury Project capsule experienced 11g.
Forecasts predict there is a 70-80% chance of good weather for Artemis 1’s launch this evening.
Let’s hope it stays that way and there isn’t any need to use the Launch Abort System this time or in the future.
You can watch the livestream of the launch on NASA’s YouTube channel.