NASA's Artemis 1 moon mission will lift off one month from today (July 29), if all goes according to plan.
That target date is not set in stone, however; the Artemis 1 team must meet a variety of checkouts and other milestones to make it happen. Indeed, Aug. 29 is just one of three "placeholder" dates in an upcoming Artemis 1 launch window, along with Sept. 2 and Sept. 5, NASA officials have said (opens in new tab). (A formal target will likely be nailed down a week or two before that window opens.)
As its name suggests, Artemis 1 will be the first mission in NASA's Artemis program of lunar exploration, which aims to establish a permanent human presence on and around the moon by the late 2020s. It will be the first flight for the powerful but long-delayed SLS and the second for Orion, which aced a quick test flight to Earth orbit back in 2014.
NASA has been gearing up for Artemis 1 for months now. For example, the agency rolled the SLS-Orion stack out to Launch Complex 39B at Kennedy Space Center (KSC) in Florida in mid-March, two weeks ahead of a "wet dress rehearsal," a crucial series of tests that included a simulated launch countdown and fueling of the SLS.
Technical issues scuttled that attempt, however, and the Artemis 1 stack was rolled off the pad and back to KSC's Vehicle Assembly Building (VAB) in late April to make some repairs.
Those fixes took about a month. The SLS and Orion were rolled back out to the pad in early June for another crack at the wet dress, which began on June 18. Technicians noticed a hydrogen leak during fueling operations on June 20 but were able to work past it, and mission team members ultimately declared the rehearsal a success.
The Artemis 1 stack rolled back to the VAB for further inspection and maintenance on July 2 and remains there still, being prepped for its impending liftoff.
Artemis 1 is a shakeout cruise designed primarily to show that SLS and Orion are ready to carry astronauts, but the mission has secondary goals as well. For example, 10 cubesats will hitch a ride on the huge moon rocket. These tiny spacecraft will perform a variety of off-Earth work, from hunting for water on the moon to solar sailing to an asteroid to testing how deep-space radiation affects yeast cells.
Artemis 1 will be a long mission, but the exact duration depends on the liftoff date, thanks to orbital dynamics. For instance, launches on Aug. 29 or Sept. 5 would result in a 42-day mission, but a Sept. 2 liftoff would kick off a 39-day flight. In every case, Orion will come back to Earth for a parachute-aided ocean splashdown.
Mike Wall is the author of "Out There (opens in new tab)" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall (opens in new tab). Follow us on Twitter @Spacedotcom (opens in new tab) or on Facebook (opens in new tab).