NASA working on plans for the new Artemis III

Artemis II is still on the way home and the existing plans for Artemis III were scrapped just over a month ago, but the agency under Jared Isaacman isn't wasting time trying to reduce the wasted time between missions. 

NASA Administrator Jared Isaacman said Tuesday afternoon that the space agency is debating about which orbit to fly Artemis III in before locking in a blueprint, noting that the first “senior level” Artemis III mission design discussion had taken place earlier in the day.
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“One of the questions is what the initial orbit will be for Artemis III,” Isaacman said during a news conference. “Is it going to be LEO or HEO? There are pros and cons for each of them, for sure.” 

Most readers will remember that Artemis III was originally scheduled as the first Artemis moon landing, and the date being talked about was originally 2025 but was most recently looking to be 2027. Artemis I was in November of '22, so about 3-1/2 years from flight one to two. Having III even at the end of '27, would be an incredible amount of progress. Plus the mission has been massively changed, so that instead of a lunar landing next year it's looking to be restricted to Earth orbit for a test of one or (preferably) both lunar landers, SpaceX's Starship-based Human Landing System or Blue Origin's Blue Moon Mark 1.

The first question, though LEO or HEO has to be decided quickly because it affects other decisions. Low Earth Orbit is commonly referred to as 100 to 1240 miles (2000 km) while High Earth Orbit ranges from there up to 22,400 miles. 

A rendezvous in low-Earth orbit would potentially allow NASA to fly the SLS rocket without using an Interim Cryogenic Propulsion Stage, or ICPS. This is valuable because it could then save this final remaining ICPS stage for the Artemis IV mission (for future SLS missions, NASA would use a Centaur V upper stage, also provided by United Launch Alliance). For an Artemis III mission in a higher orbit, however, NASA would need the ICPS to push Orion there. 

A rendezvous in high-Earth orbit would better mimic thermal and other conditions near the Moon, and this might be a more benign environment for the Orion spacecraft, which is sensitive to thruster pluming and other thermal issues. High-Earth orbit would also provide a stiffer test for Orion’s modified heat shield.

The concept of doing this mission as a test of rendezvous and docking with the lunar landers is just plain common sense. It was done during the Apollo program two missions before Apollo 11's first landing. Apollo 9 took place in low-Earth orbit between 125 and 310 miles.  

The biggest question hanging there in my mind is which lander will be ready before the end of '27. Will they both be ready? The answer is both seem to be progressing as intended. The launch of the next Starship test flight was said to be "in March" but I've seen May mentioned lately. Part of that could be there was a latest version Raptor 3 engine that blew up in the last week during testing, but while engines blowing up isn't necessarily a design problem, it seems prudent to make sure it's not something that needs redesign. Blue Origin’s Blue Moon Mk. 1 lander is said to be “wrapping up” vacuum-chamber testing at Johnson Space Center in Houston.

Blue Origin's Blue Moon Lander. Image credit: Blue Origin

Final words to Eric Berger from Ars Technica.

Isaacman said it is important for SpaceX’s Starship and Blue Origin’s New Glenn rocket to reach higher launch cadences to support not just Artemis III but many future missions to the lunar surface. NASA is clearly watching both closely.

“We’ll all have a sense of which path we’re going to go down based on launch cadence of our two HLS (human landing system) providers, both of which have launches coming up in the next month or less,” Isaacman said. “A big key to our strategy—to not just return to the Moon but to stay and build a base—is the rapid reusability of heavy-lift launch vehicles. The more they get experience doing that, the more options that are available to us for Artemis III.”