NASA juggling piloted moon mission and space station crew replacement flight

With a space station medical evacuation safely completed, NASA is focused on two challenging missions proceeding in parallel: launching four astronauts on a flight around the moon, at the same time as the agency is planning to send four replacement astronauts to the International Space Station.

Engineers plan to haul the Artemis 2 moon rocket to launch pad 39B at the Kennedy Space Center on Saturday for tests leading to launch early next month on a historic piloted flight around the moon.

At the same time, NASA is gearing up to launch four Crew 12 astronauts to the space station, possibly while the Artemis 2 moon mission is underway, to replace four Crew 11 crew members who cut their mission short and returned to Earth ahead of schedule Thursday because of a medical issue.

The Artemis 2 mission and Crew 12’s planned space station flight present a unique challenge for NASA. The agency has not managed two piloted spacecraft at the same time since a pair of two-man Gemini capsules tested rendezvous procedures in low-Earth orbit in 1965. The agency has never flown a deep space mission amid another launch to Earth orbit.

“This is exactly what we should be doing at NASA,” Jared Isaacman, NASA’s new administrator, said Thursday. “We have the means as an agency … to be able to bring our astronauts home at any time … while making preparations to pull forward our next mission, like Crew 12, while also progressing on our Artemis 2 campaign.”

He described the moon mission as “probably one of the most important human spaceflight missions in the last half century.”

The world’s most powerful rocket booster

NASA’s towering 322-foot-tall Space Launch System rocket, the most powerful operational booster in the world, will be hauled out of the cavernous Vehicle Assembly Building early Saturday atop an upgraded Apollo-era crawler transporter. Including at least one stop along the way, the 4-mile move to the pad is expected to take eight to 10 hours.

“It takes us a little while to get out of the building,” said Launch Director Charlie Blackwell-Thompson. “But about an hour after we get that first motion, you’ll begin to see that beautiful vehicle cross over the threshold of the VAB and come outside for the world to have a look.”

Once at the pad, engineers will carry out a variety of tests and work to ready the rocket and its Orion crew capsule for blastoff early next month on the Artemis 2 moon mission.

“It really doesn’t get much better than this,” John Honeycutt, chairman of the Artemis 2 Mission Management Team, told reporters Friday. “We’re making history.”

Commander Reid Wiseman, Victor Glover, Christina Koch and Canadian astronaut Jeremy Hansen planned to be on hand for the rollout. If all goes well, the crew will test the Orion capsule in Earth orbit before heading into deep space, flying farther from home than any other humans as they loop around the far side of the moon.

Artemis 2 mission plan

The Artemis 2 mission follows a similar flight in 2022 that sent an unpiloted Orion capsule around the moon to pave the way for next month’s flight. The Artemis 2 mission, in turn, will set the stage for Artemis 3, a long-awaited and oft-delayed mission to land astronauts near the moon’s south pole. The current target date for Artemis 3 is 2028.

Despite Saturday’s planned rollout, the Artemis 2 launch date is still uncertain.

It will depend in large part on the results of a fueling test around the first of the month when engineers plan to load the booster’s 21-story-tall first stage with 733,000 gallons of super-cold liquid hydrogen and oxygen along with a full load of propellants for the booster’s 45-foot-tall second stage, the Interim Cryogenic Propulsion Stage, or ICPS.

During tests of the SLS rocket used for the Artemis 1 mission in 2022, multiple fueling tests had to be carried out before engineers finally resolved a series of propellant leaks. The SLS rolling out on Saturday features multiple upgrades and improvements to minimize or eliminate any such leakage.

If the upcoming fueling test goes well, Wiseman and his crewmates could be cleared to blast off a few days before Feb. 11, the end of next month’s launch period. If any major problems are found during the propellant loading exercise, Artemis 2 likely will slip to early March when the next set of launch windows becomes available.

Next space station crew

Amid the work to ready the Artemis 2 rocket for launch, NASA managers are also working to move up the launch of the Crew 12 space station crew. Commander Jessica Meir, Jack Hathaway, European Space Agency Sophie Adenot and cosmonaut Andrey Fedyaev are officially scheduled for launch on Feb. 15.

The crew they are replacing, Crew 11 commander Zena Cardman, Mike Fincke, Japanese astronaut Kimiya Yui and cosmonaut Oleg Platonov, originally expected to return to Earth around Feb. 20 after helping familiarize their replacements with the intricacies of space station operation.

But Crew 11 was ordered to cut their mission short after one of the crew members developed a medical issue of some sort. They returned to Earth Thursday, leaving just three people aboard the space station: cosmonaut Sergey Kud-Sverchkov, Sergey Mikaev and NASA astronaut Chris Williams. They were launched to the outpost in November aboard a Russian Soyuz spacecraft.

NASA and SpaceX are working to move up the Crew 12 launch date to minimize the gap between the two NASA missions. Depending on where it ends up, NASA could be orchestrating a launch to the International Space Station while the Artemis 2 crew is flying around the moon.

“I don’t see any reason why we wouldn’t continue along those parallel paths,” Isaacman said. “And if it comes down to a point in time where we have to de-conflict between two human spaceflight missions, that is a very good problem to have at NASA.”

Jeff Radigan, lead flight director for Artemis 2, agreed it made sense to continue preparing for both missions.

“I know the agency is preparing to launch Crew 12,” he told reporters. “There are a lot of preparations going on, but there absolutely are constraints.”

“It’s not prudent for us to put both of those up at the same time, but we also have to ensure that both of them are ready to go. We may run into an issue, and the last thing we want to do is make a decision too early and then lose an opportunity. That would not be responsible of us.

“So, we need to keep pressing with both missions, we need to ensure that we’re doing that at the right speed, and we’re looking at the right technical constraints. As we get closer, either the decision will come about because the hardware’s talking to us and we have an issue that we have to go deal with, or we have to pick one.”

But, he added, “that doesn’t mean we should stop preparing for either mission right now, but we need to do that at the right pace.”