Before the Artemis II crew can go to the moon, they need to master flying high above Earth

After more than 50 years, NASA is going back to the moon. If all goes as planned, the Artemis III mission will see two astronauts stepping foot on the lunar surface sometime in 2025. Subsequent Artemis missions involving the construction of a lunar space station and a permanent base on the lunar south pole could follow every one to two years, funding permitting.

But before the 21st-century moon landing, NASA wants to ensure its astronauts’ ride, the Orion spacecraft, is up to the task. The successful, uncrewed Artemis I put the new Orion space capsule and Space Launch System (SLS) rocket’s propulsion and navigation systems to the test. The recently announced crew of four astronauts for Artemis II, scheduled for November 2024, will take the next leap by giving Orion a full shakedown of its manual flight and life support systems.

“We’ll be the first humans to fly on the spacecraft,” says Artemis II Commander Reid Wiseman. “We need to make sure our vehicle can keep us alive when we go into deep space.”

That makes the Artemis II mission unique, in that its primary focus is not exploration nor science experiments, but technical preparation for the astronauts on subsequent Artemis exploits. “Our focus is on what we can do to enable our co-workers to operate in the lunar environment, whether it’s on the Gateway outpost [a space station NASA plans to build in lunar orbit beginning in 2024] or the lunar surface,” Wiseman says.

To achieve that goal, Wiseman and his crewmates, NASA astronauts Christina Koch and Victor Glover, as well as Canadian astronaut Jeremy Hansen, will kick off their 10-day flight with a series of highly elliptical orbits around the Earth. These rounds are designed to give them about 24 hours to test out their spacecraft and allow for an easy mission abort path to return home if any problems arise.

“That first 24 hours is really going to be intense. Looking at the crew timeline, you can barely fit everything in,” Wisemans says of all the spacecraft testing his team will conduct. “And then when we get finished with all of that, our reward is translunar injection,” the engine firing maneuver that will set the spacecraft on a course out of Earth’s orbit and toward the moon.

[Related: NASA’s uncrewed Orion spacecraft will get a hand from a Star Trek-inspired comms system]

About 40 minutes after launching from the Kennedy Space Center, the upper stage of the SLS rocket known as the Interim Cryogenic Propulsion Stage (ICPS) will boost Orion into an ellipse that will carry the crew about 1,800 miles above the Earth at its highest point, and about 115 miles at its lowest.

After initial checks during that roughly 90-minute first orbit, the ICPS will fire again to boost the spacecraft into a much higher ellipse around the planet, this time reaching as high as 46,000 miles above it—far outstripping the 250-mile altitude where the International Space Station usually flies. This second orbit will take nearly 24 hours and is where the crew will do the most serious assessments on Orion’s systems.

“We’re gonna try to test out every manual capability that we have on Orion: manual maneuvering, manual targeting, manual communications set up,” Wiseman says. In effect, they’ll be simulating what it takes to prepare the capsule for a lunar landing—but in the Earth’s orbit, not the moon’s.

A crucial part of the testing will involve what NASA calls a ”proximity operations demonstration.” Orion and the European-built service module, which carries life support, power, and propulsion systems, will detach from the ICPS as the crew practices manual maneuvering to align their spacecraft with the discarded upper stage of the rocket. While they will not actually dock with the ICPS, they will run the systems that future Artemis crews need to dock with a lunar lander or the Lunar Gateway before journeying to the moon’s surface.  

Next, the crew will conduct support and communications checks to ensure the Orion spacecraft is ready to head into deep space. If given the go-ahead by mission control, they will use the Orion spacecraft’s main engines to conduct a translunar injection burn designed to carry the spacecraft on a looping path around the moon, reaching a peak distance of about 230,000 miles from Earth. It will take about four days just to travel to and from the moon.

Artemis II stands out from the other missions in its series in that the Orion main engine will carry out the translunar injection burn, rather than the ICPS, which will have used up its fuel boosting the capsule into the high elliptical orbit around the Earth for testing. And because Artemis II will not involve landing on the moon, the crew doesn’t have to perform an orbital insertion burn, and will instead simply loop around the moon, ultimately passing around the far side of the satellite at about 6,400 miles altitude, relying on Earth’s gravity to pull the spacecraft home without the need for another engine burn.      

The crew will have plenty of other tests during the long lunar tour to keep them occupied, according to Wiseman. While the exact science packages for the mission have yet to be announced, the astronauts’ bodies will serve as mini laboratories over the course of the flight—and after.

[Related: Artemis I’s solar panels harvested a lot more energy than expected]

“As a human explorer, there’s going to be a load of science on us, like radiation and how we handle the deep space environment,” Wiseman says. “We know a lot about humans operating in space on the International Space Station; we don’t know as much about humans operating in deep space.”

The crew leader says he is honored to be commanding Artemis II, even if that means he may not fly on Artemis III or subsequent missions. “Personally, what I really want to do is I want to go fly Artemis II, I want to come back, and I want to help my crewmates train for their missions,” he explains. “Then I want to be the largest voice in the crowd cheering for them when they get assigned to Artemis III or IV.”