NASA’s Artemis 1 mission, launched on November 16th, 2022, has become the first vehicle capable of carrying humans that far, to return to the vicinity of the Moon since Apollo 17 in 1972.
The Orion capsule reached the Moon on Monday, November 20th, the fifth flight day of the mission overall. At 12:44 UTC, the vehicle, swinging around the far side of the Moon and so out of communications with Earth, closed to within 130 km of the lunar surface and a velocity of 862 km/h. It then fired the single motor mounted on the vehicle’s service module for 2.5 minutes, the first engine burn designed to push the vehicle into a distant retrograde orbit (DRO).
The DRO is a path that loops the vehicle away from the Moon in the opposite direction to the Moon’s own orbit around the Earth. Confirmation of the manoeuvre’s success came as the vehicle cleared the Moon and resumed communications with Earth – returning a colour image of our home in the process.
The DRO provides a highly stable orbit where little fuel is required to stay for an extended trip in deep space to put Orion’s systems to the test in an extreme environment far from Earth.
– NASA blog post
An hour later, as the vehicle proceeded away from the Moon, it passed over a historic landmark – Tranquillity Base, the landing zone for Apollo 11 in 1969 at a distance of 2,227 km. It continued outwards from the Moon with all systems functioning as expected. However, on Wednesday, November 23rd, all contact with the vehicle was suddenly lost and remained so for 47 minutes prior to contact being re-established.
The cause of loss-of-contact lay with the reconfiguring of the communications link between the spacecraft and NASA’s Deep Space Network (DSN) – the orbiting and ground-based communications network used to maintain contact with all of NASA’s operational missions. The reconfiguration should have been routine, having been carried out several times during the mission as DSN carried out its multiple duties, and at the time of writing it was not clear what caused the glitch.
At 21:52 GMT on Friday, November 25th, Orion made its second DRO engine burn, one that lasted 82 seconds, sufficient to push the vehicle into its outward loop away from the Moon travelling at 396 km/h. This outbound leg of the flight saw Artemis 1 breaking the record for the for the farthest distance from Earth travelled by a human-rated spacecraft, surpassing the 432,000 km distance set by Apollo 13 in April 1971; Artemis will reach a maximum distance from Earth of 435,000 km on Monday, November 28th, the point marking the start of its return to close proximity to the Moon, which it will reach on December 1st.
The mission has not all been smooth sailing, however. As noted in my previous Space Sunday update, the launch facilities at Kennedy Space Centre suffered damage during the Artemis 1 launch, although at the time of that article, NASA had not confirmed how much damage had occurred on the mobile launch platform.
Immediately following the launch, NASA asked the media not to image or record the launch platform and tower, citing security issues and ITAR (International Traffic in Arms Regulation), sparking speculation (particularly among SpaceX fans) that the Space Launch System rocket have caused considerable damage to its launch facilities and was therefore somehow a “failure”.
Since then, however, NASA has completed an initial damage assessment exercise and has been more forthcoming. Whilst a more in-depth assessment is required on the internals of the launch tower structure, the initial assessment suggests the launch platform overall faired a lot better than expected, given the huge strain it was under (SLS generates more thrust and heat than either the space shuttle vehicles or the Apollo Saturn V at launch).