This will be NASA’s second attempt to launch its enormous next-generation rockets this week. The first launch attempt on Monday was cancelled when one of the four RS-25 engines failed to achieve the required temperature for liftoff.
The Space Launch System (SLS) rocket, with the Orion crew capsule atop, is the centrepiece of the Artemis I mission. If the launch goes well, SLS will lift the uncrewed Orion to an altitude of just under 4,000 kilometres before the two vessels separate and the core stage of the rocket falls back to Earth.
