Four astronauts are currently en route to the Moon for NASA's Artemis II mission, a crucial rehearsal for future lunar landings. This historic 10-day journey marks humanity's return beyond Earth orbit since 1972. The crew will test vital systems and human performance in deep space, with a close lunar flyby scheduled for April 7.Four astronauts are currently en route to the Moon for NASA's Artemis II mission, a crucial rehearsal for future lunar landings. This historic 10-day journey marks humanity's return beyond Earth orbit since 1972. The crew will test vital systems and human performance in deep space, with a close lunar flyby scheduled for April 7.