Apart from pesky issues with the spacecraft's toilet and waste disposal system, most of the Artemis II mission has proceeded like clockwork. NASA has made few changes to the flight plan since the launch of the lunar flyby mission on April 1.
But ground controllers revamped the timeline Wednesday as the Artemis II astronauts zoomed toward Earth after a close encounter with the Moon earlier this week. The four astronauts were supposed to take manual control of their Orion spacecraft, named Integrity, for a piloting demonstration Wednesday night.
Instead, mission managers canceled the demo to make time for an additional test of the ship's propulsion system. The goal was to gather data on a "small leak" of helium gas, which Orion uses to push propellant through a series of tanks and pipes to feed the spacecraft's rocket engines, said Jeff Radigan, NASA's lead flight director for the Artemis II mission.