NASA's Artemis 1 mission closes the hatch on the Orion spacecraft

huge artemis 1 rocket on the launch pad at night
The Artemis 1 megarocket stands ready for a moon launch at the Kennedy Space Center in Florida. (Image credit: NASA/Joel Kowsky)

NASA's lunar spacecraft is sealed up for launch.

Artemis 1 technicians closed the door on the Orion spacecraft Thursday (Aug. 25) in preparation to launch to the moon on Monday (Aug. 29) atop the Space Launch System (SLS) megarocket.

"The crew module hatch was closed at approximately 3:30 a.m. Thursday," NASA stated in a blog post describing some of the last steps before liftoff from the agency's Kennedy Space Center in Florida.

"Meteorologists with the U.S. Space Force Space Launch Delta 45 currently predict a 70% chance of favorable weather conditions for launch on Aug. 29," the agency added. Periodic rain showers remain the primary concern for launching on time at 8:33 a.m. EDT (1233 GMT), although the launch window does extend for two hours.

Related: NASA's Artemis 1 moon mission: Live updates
More: NASA's Artemis 1 moon mission explained in photos

Artemis 1 is the debut installment of the Artemis program, which aims to put astronauts around the moon in 2024 with Artemis 2 and upon the lunar surface in 2025 with Artemis 3. NASA is framing the program as an opportunity to test out technology, procedures and hardware ahead of bringing humans to Mars.

The uncrewed Artemis 1 will loop around the moon for an approximately 40-day mission to test the system's endurance against radiation, space weather, cold and other factors of the space environment ahead of certifying it for humans.

The two-day countdown for Artemis 1 will begin on Sunday (Aug. 28) as the SLS rocket targets its first-ever launch. The booster, which is the most powerful NASA has yet built, has gone through numerous ground tests including a near 50-hour-long "wet dress rehearsal" fueling testing in June.

U.S. Vice President Kamala Harris will be among the attendees at the launch on Monday, her office confirmed in an exclusive to published Friday (Aug. 26). Harris will tour KSC and deliver a speech concerning NASA space leadership.

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: