CAPE CANAVERAL—Following an 11-hr. flight readiness review (FRR), NASA on Aug. 22 cleared the first Space Launch System (SLS) rocket and Orion spacecraft for a launch on the kickoff mission of the Artemis program, a U.S.-led initiative to establish a permanent human presence in deep space.

“This day has been a long time coming,” NASA Associate Administrator Bob Cabana says. “The review, as thorough as it was, in no way encompasses the amount of work the team did to get us here.”

The Kennedy Space Center launch team is aiming for an 8:33 a.m. EDT Aug. 29 liftoff from Launch Complex 39B to begin Artemis I, an uncrewed flight test designed to push the operational envelope of the Orion spacecraft.

If successful, the two-stage SLS—lifting off with 8.8 million lb. of thrust—will put the Orion spacecraft on a trajectory that brings it close enough to be captured by the Moon’s gravity. Orion is aiming for what is known as a distant retrograde orbit, which is a highly stable, elliptical path ranging from 62-40,000 mi. from the lunar surface that requires little fuel to maintain.

At its most distant point, the solar-powered Orion will travel some 30,000 mi. beyond where the Apollo 13 astronauts flew in 1970, the current record for the most distant human spacecraft.

The primary goal of the mission is to test the ablative heat shield that will protect Orion during its Mach 32 re-entry into Earth’s atmosphere, targeted for Oct. 10.

“This is a test flight,” Cabana told reporters during the post-FRR press conference. “It is not without risk. We have analyzed the risk as best we can and we’ve mitigated it as best we can, but we are stressing Orion beyond what it was actually designed for, in preparation for sending it to the Moon with a crew.”

For example, Orion is designed to support a crew of four for 21 days in the highly radioactive environment of deep space. The Artemis I uncrewed flight test is scheduled to last 42 days. “We’re doing something that is incredibly difficult to do and does carry inherent risk in it,” Artemis Mission Manager Michael Sarafin says.

With final vehicle testing and closeouts proceeding smoothly, NASA planned to start the 45-hr., 10-min. countdown clock for launch of Artemis I on Aug. 27.