by 
NASA’s Artemis 1 moon rocket begins its “wet-dress rehearsal” tonight (June 18) and begins a series of pivotal launch countdowns that will last through Monday (June 20).
If all goes well, the massive Space Launch System (SLS) rocket and Orion space capsule could be on its way to the moon before the end of summer.
The wet dress rehearsal is scheduled to begin today with a call to ground team stations at NASA’s Kennedy Space Center (KSC) in Florida at 5:00 p.m. EDT (2100 GMT). Over the course of approximately 48 hours, the Artemis 1 team will load cryogenic fuel into the huge rocket’s first and second stages. If the crews experience no complications tonight or tomorrow, propellant loading is scheduled to begin Monday at 7:00 AM EDT (1100 GMT).
Live updates: NASA’s Artemis 1 Moon Mission
Related: NASA’s Artemis 1 Moon Mission Explained in Photos
This marks the second time the Artemis 1 stack has been atop KSC’s historic Launch Complex 39B, which first served as a trail for NASA’s Apollo moon missions. Artemis 1 – the debut launch for SLS – sends an unmanned Orion spacecraft around on a month-long mission the moon and back. If successful, NASA plans to fly astronauts aboard the next two Artemis missions, with the space agency monitoring a moon landing on Artemis 3 in 2025 or 2026.
The Artemis 1 stack has been on Pad 39B since June 6, after spending more than a month in KSC’s Vehicle Assembly Building (VAB). NASA’s first visit to an Artemis 1 wet dress rehearsal took place in early April this year. Over several days, NASA technicians tried to fuel the rocket three times, but they failed to fuel the rocket. Mechanical issues and leaks discovered during cryogenic fuel transfer finally violated April’s wet clothing rehearsal and SLS became rApril 25th back to the VAB for repair†
If Monday morning’s fuel load goes according to schedule, NASA is aiming for a simulated countdown from the 2:40 p.m. EDT (1840 GMT) launch. However, NASA has built in two extra hours to account for any additional testing that needs to take place during the propellant loading. Ground teams first load the core stage of the SLS and then proceed to the top stage of the launch vehicle, the Interim Cryogenic Propulsion Stage (ICPS).
Speaking to reporters earlier this week, Charlie Blackwell-Thompson, Artemis launch director at the Exploration Ground Systems Program at KSC, said successfully refueling each stage will be a significant achievement. “Provided we hit those milestones, we’ll move on to our terminal count,” Blackwell-Thompson said.
Once the rocket is successfully fueled, mission operators plan to bring the countdown clock to T-30 before it is first held. Systems are stopped and recycled before starting a new terminal countdown, bringing the clock all the way to T-10 seconds before starting a final countdown.
If testing goes smoothly, SLS and Orion will be on the trail for a few more days for technicians to prepare the stack for its journey back to the VAB. The Artemis 1 team will then analyze the data from the wet dress and any necessary maintenance work on the rocket or mobile launch tower will be performed.
Barring further hiccups in the vehicle or ground systems during this wet dress rehearsal, NASA officials hope to launch Artemis 1 as early as the end of August. But they won’t pick a target date until all wet clothing data has been fully analyzed and they’re confident the rocket is truly ready to fly.
follow us on twitter @Spacedotcom (opens in new tab) or on facebook (opens in new tab)†
