At this stage of Artemis 2’s journey home, what really counts is no longer the lunar fly by, but the ability of Orion to demonstrate its readiness to repeatedly take crews safely back from the depths of space. With Artemis 2 now on its eighth day of flight, the four crew members on board the spacecraft are at the calmest stage of the mission after all, their exciting trip around the moon was completed successfully. Now, in the run up to returning home, the astronauts need to conduct tests that will be critical for future missions involving lunar flights: performing radiation protection exercises, testing the operation of thrust engines, practicing manual piloting and completing a number of activities required for reentry and recovery.
According to NASA, the Artemis 2 mission will be a deep space test flight of the Orion Crew Module with crew on board, which makes the technical importance of the return leg understandable. The spacecraft has already proved its ability to ferry astronauts into deep space, fly by the Moon on a free return trajectory, and provide a comfortable environment away from the planet. However, to make sure that the vehicle is capable of taking astronauts to the Moon and then bringing them back, the spacecraft needs to prove its capabilities and reliability in the closing phases of a mission: operating with tired crews, conducting navigation procedures, controlling its attitude, ensuring comfort, and planning the safest possible landing. The NASA’s Artemis II mission overview mentions verification of Orion’s life support, propulsion, power, thermal and navigation performance with a crew on board in the real deep space environment as the main objective of the mission.
One of such areas is radiation readiness of the spacecraft. Vehicles going to the Moon do not have the protection provided by the Earth’s magnetic field. Therefore, astronauts must be prepared for a possible increase in radiation activity and know how to build a shelter using available supplies such as food in case of increased exposure. Radiation testing performed during Artemis 2 involves stacking food supplies in the right way inside Orion to provide protection.
Orion’s testing of its attitude control system also deserves special mention because it is essential to evaluate it for further Artemis missions. To ensure the efficient functioning of the spacecraft in its return journey to Earth, its attitude had to be adjusted and controlled in two different modes, including a fuel efficient one that involved some drifting, however. Such evaluation is a fundamental component of Artemis 2 as an engineering project, since a spacecraft that regularly travels to the Moon should perform predictable maneuvers, save on propellant and still remain controllable for humans and computer programs.
This mission also demonstrates the importance of the human factor: astronaut Christina Koch said during an onboard conversation with the International Space Station “just made it even more special” such “truly emphasized how alike we are.” This feeling perfectly fits the mission goals as they involve not only verifying spacecraft and technologies, but also restoring human presence in deep space after a 53 year break.
Finally, the culmination of return procedures will be the splashdown off the coast of San Diego at about 8:07 p.m. EDT on April 10, followed by recovery by US Navy units. The spacecraft is expected to enter Earth’s atmosphere at very high speeds, and then land with the aid of parachutes. The weather conditions will become yet another criterion for defining the recovery time window. All in all, while flying by the Moon is indeed an impressive part of Artemis 2, it is actually a rehearsal of a complete crew transportation system.