LOS ANGELES, Feb. 20 (Xinhua) -- NASA on Thursday completed a key wet dress rehearsal for its Artemis II crewed lunar mission, successfully fueling its Space Launch System rocket and demonstrating the launch countdown sequence at the agency's Kennedy Space Center in the U.S. state of Florida.
During the rehearsal, engineers loaded more than 700,000 gallons of liquid propellant into the rocket, deployed a closeout crew to the launch pad to demonstrate closing the Orion spacecraft hatches, and carried out two runs of terminal count -- the final phase of the launch countdown, according to NASA.
A wet dress rehearsal is a full prelaunch test designed to fully fuel the rocket and verify countdown procedures prior to launch. NASA conducted a previous rehearsal on Feb. 3, but the countdown was halted due to a liquid hydrogen leak.
During Thursday's test, teams closely monitored hydrogen fueling operations, which had posed challenges in earlier attempts. Hydrogen gas concentrations remained under allowable limits, giving engineers confidence in new seals installed in an interface used to route fuel to the rocket.
NASA said a temporary loss of ground communications occurred early in fueling operations at the Launch Control Center. Operators switched to backup communication systems to maintain safe propellant loading before normal communications were restored. Engineers later identified the equipment responsible for the disruption.
"When we did the test three weeks ago, the hardware was talking to us, so we listened," John Honeycutt, chair of the Artemis II Mission Management Team, said during a news conference Friday. "The remediation activities that we took turned out really well."
Although NASA has not announced a formal launch date, the agency said preparations are underway to preserve flexibility within the March launch window.
The Artemis II mission will send four astronauts on an approximately 10-day journey around the Moon and back. The crew consists of NASA astronauts Reid Wiseman, Victor Glover and Christina Koch, and Canadian Space Agency astronaut Jeremy Hansen. ■
