The Artemis I mission is ready to launch.
That's the result of NASA's Flight Readiness Review, which was conducted on Monday. The review was an in-depth assessment of the preparedness of the 322-foot-tall (98-metre-tall) stack, consisting of the Space Launch System rocket and Orion spacecraft, currently sitting on the launchpad at NASA's Kennedy Space Center in Florida.
The Artemis team is targeting its first two-hour launch window from 8:33 a.m. ET to 10:33 a.m. ET on Monday, August 29. There are backup launch windows on September 2 and September 5.
The "go" following the flight readiness review is a positive sign that things are on track for the mission, but there are still factors over the next week that could impact when it lifts off the pad, including bad weather.
Very little remains on the task list after previous testing rounds of the rocket on the launchpad during wet dress rehearsal, which simulated every step of launch without lifting off. There remains an open item the team will test on launch day, said Mike Sarafin, NASA's Artemis mission manager.
The hydrogen kick start, used to thermally condition the engines, did not occur during the final wet dress rehearsal, so this process is now a component of the launch countdown. This test will occur during a "quiescent point" ahead of the final countdown, said Charlie Blackwell-Thompson, Artemis I launch director at Kennedy Space Center.
The rocket stack arrived at the launchpad on August 17 after a 4-mile (6.4-kilometre) ride aboard one of the Apollo-era giant NASA crawlers from the Vehicle Assembly Building -- just like the shuttle missions and Apollo Saturn V rockets once did.
The uncrewed Artemis I will launch on a mission that goes beyond the moon and returns to Earth. Once it launches, the spacecraft will reach a distant retrograde orbit around the moon, travelling 1.3 million miles (2.1 million kilometres) over the course of 42 days. Artemis I will splash down in the Pacific Ocean off the coast of San Diego on October 10. Orion's return will be faster and hotter than any spacecraft has ever experienced on its way back to Earth.
The Orion spacecraft will travel farther than any spacecraft built for humans has ever flown, reaching 40,000 miles (64,000 kilometres) beyond the far side of the moon, according to NASA.
There are no humans onboard, but Orion will carry 120 pounds (54.4 kilograms) of mementos, including toys, Apollo 11 items and three mannequins.
Sitting in the commander's seat of Orion will be Commander Moonikin Campos, a suited mannequin that can collect data on what future human crews might experience on a lunar trip. The mannequin will wear the new Orion Crew Survival System suit designed for astronauts to wear during launch and reentry. The suit has two radiation sensors.
This mission will kick off NASA's Artemis program, which aims to return humans to the moon and land the first woman and first person of colour on the lunar surface by 2025 -- and eventually make way for human exploration of Mars.
Artemis I will also carry a number of science experiments, some of which were installed once the rocket and spacecraft arrived at the launchpad.
This week, the Artemis team will open the hatch to Orion one more time to install a plush Snoopy toy, who will serve as the mission's zero gravity indicator. Once the spacecraft reaches the microgravity environment of space, Snoopy will float through the crew capsule.
Bob Cabana, the associate administrator for NASA Headquarters in Washington, DC, reflected on watching the Apollo 13 launch as a young midshipman at the US Naval Academy.
"I never dreamed I'd end up being an astronaut, let alone director of the Kennedy Space Center or in the position I'm in now," Cabana said. "I'm a product of the Apollo generation and look what it did for us. And I cannot wait to see what comes from the Artemis generation because I think it's going to inspire even more than Apollo did. It was rewarding to be able to see all that work during the review today and know that we are ready to go do this."