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NASA’s test of its massive moon rocket is underway today

NASA is conducting one of the last major tests of its new Space Launch System rocket and Orion spacecraft before its first uncrewed mission to the moon, tentatively scheduled for later this year. Known as the wet dress rehearsal, the test involves rolling the rocket out to Launch Pad 39B at NASA’s Kennedy Space Center in Florida and filling it with fuel and performing a countdown, but not actually launching it.

The test runs over the weekend, lasting for two days as the team performs the same preparation sequence that would be used for a real launch. With the rocket on the pad, the teams will power on various systems of both the rocket and the Orion spacecraft it carries, before loading the rocket with over 700,000 gallons of super-cold liquid fuel — hence the name “wet” dress. Once the rocket is filled with fuel, the team will perform a countdown to launch, check whether the countdown clock can be recycled if necessary, and then drain the fuel out of the tanks. The test involves coordinating personnel across the Launch Control Center at Kennedy, the Mission Control Center at NASA’s Johnson Space Center in Houston, the Space Force Eastern Range, and the SLS Engineering Support Center at the Marshall Space Flight Center in Huntsville, Alabama.

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Space Launch System ready for wet dress rehearsal, a sunrise in the background.
Space Launch System ready for wet dress rehearsal. NASA

“At approximately 5 p.m. EDT, or L-45 hours, 40 minutes before the initial targeted test T-0, the launch team arrived at their stations inside the Launch Control Center at NASA’s Kennedy Space Center in Florida,” NASA wrote in an update. “The countdown is now underway for the wet dress rehearsal test for NASA’s Artemis I mission.”

This test is unusual in that no press is allowed to attend in person, which is not typical for such tests. Also, while there is a livestream of the rocket on the pad available from the Kennedy Space Center newsroom, this feed is video-only and does not include any audio or commentary. The lack of independent press access to such a major test has raised questions from the space community, but NASA says this decision is due to national security concerns, according to SpaceFlightNow.

The test will continue over today, Saturday, April 2, and through tomorrow, Sunday, April 3. You can see the full schedule of events on the Artemis blog.