“We are 41,541 miles from the moon,” says astronaut Reid Wiseman, commander of Artemis II, NASA’s upcoming mission returning to the moon. There’s a lot of pressure on Wiseman and his fellow astronauts. They are laying the groundwork for an effort will land astronauts on the lunar surface for the first time in over 50 years.
But there’s no tension in Wiseman’s voice right now. He’s relaxed and comfortable, wearing a blue long-sleeve shirt with “ARTEMIS” emblazoned on the front. In front of him is a series of glass displays, surrounded by the switches and lights that show him the status of the Orion spacecraft, which will take Wiseman and three others on a trip around the moon.
There are five windows on the command module of the Orion capsule—Apollo had the same number. Looking through them, Wiseman doesn’t see the vast emptiness of space, or glimpses of the Earth or moon. Instead, he sees a simulated view of a field of stars. Wiseman is in one of many mockups of the Orion capsule, practicing one part of the mission, trying to understand what he will face when Artemis II launches next year.
Four astronauts—Commander Wiseman, Pilot Victor Glover, and Mission Specialists Christina Koch and Jeremy Hansen of the Canadian Space Agency—have practiced every aspect of this mission since they were announced as its crew in May of 2023. They officially started training a month later. Since then, they’ve learned to operate the spacesuits that could keep them alive for up to 144 hours if there’s a loss of atmosphere in the capsule.
They’ve performed countless simulations to understand everything that could go wrong, from engine failures to a broken toilet. Once, during a 30-hour simulation, Glover chose to sleep in the Orion capsule simulator instead of heading to the crew quarters with the other three astronauts. “This vehicle, the life support system has this kind of heartbeat sound,” Glover told National Geographic. He wanted to experience what it was like to sleep in that environment.
In 2022, the Artemis I mission put NASA’s Space Launch System (SLS) and Orion crew casuple to the test. Here, it is at the vehicle assembly building at Kennedy Space Center in Florida. Photograph by Dan Winters, Nat Geo Image Collection
In 2022, Artemis I tested out the ground systems, rocket, and spacecraft without a crew. Now, Artemis II is set to send humans around the moon. This crew will travel farther than any humans ever have before.
And now, it’s almost here. The official launch date is April 2026 (no specific day has been chosen yet), though NASA is quietly working towards as early as February 5. The mission will lift off on the Space Launch System (SLS), a NASA megarocket specifically designed for the Artemis program that will take astronauts into Earth orbit. After the rocket separates, Orion’s main engine will put the spacecraft into a long slingshot around the moon. Scheduled for almost 10 days, Artemis II won’t land on the moon. That feat is reserved for Artemis III, currently scheduled for mid-2027.
“Every single day feels more and more real, more and more chances to do the actual mission with the actual folks we’re going to be with,” said Koch in a press conference in early August.
As the launch date creeps closer, Glover tells National Geographic he’s laser focused on the mission. “For me, feelings can be a distraction,” Glover says when asked about how excited he is. “Ask me that question again when we get through the mission and I’ll give you all the touchy-feely answers.”
But why is Artemis II so important, despite it not featuring a lunar landing? Simply put: It will kick off an entirely new era of human exploration of the cosmos.
The goal of the Apollo program was to land humans on the lunar surface. It wasn’t designed to keep us there. “Unlike Apollo, this time when we go to the moon we want to stay,” says Lori Glaze, acting associate administrator for the Exploration Systems Development Mission Directorate at NASA. “We want to be able to have a sustained presence on the moon. We want to be able to go back over and over again for years, really learn how to live and work in this environment that’s a little bit further away from Earth.”
Artemis II is the next step.
Artemis I and II are test flights for a new chapter of human exploration
Artemis, the sister of Apollo in Greek mythology, has been decades in the making. Its seeds were sown in 2004 with what was then called the Constellation program. That’s when development of Orion and SLS began in an effort to return to the moon. Constellation was eventually cancelled in 2011. But the work on SLS and Orion wasn’t scrapped completely. When Artemis was announced in 2017 as part of NASA’s Moon to Mars program, they were repurposed.
The first mission of the program, Artemis I, lifted off on November 16, 2022. The uncrewed flight to test the equipment was, overall, a success. From the first thundering moments of liftoff to the separation of its second stage from the Orion capsule in Earth orbit, SLS met or exceeded all NASA expectations.
Orion was a different story; an unexpected problem arose with the capsule’s heat shield.
The Orion capsule from the Artemis I mission makes its way towards the the USS Portland after being successfully secured by NASA and US Navy teams off the coast of Baja California, Mexico, on December 11, 2022. Photograph by Caroline Brehman, Pool/AFP/Getty Images
Orion is a cone-shaped capsule that turns its blunt end to the Earth’s atmosphere during re-entry. There lies the heat shield, made up of a material called Avcoat. It’s designed to ablate away from the spacecraft. It literally takes the heat of re-entry with it as it melts off, protecting the ship and the crew inside from extreme temperatures.
At least, that’s how an ablative heat shield is supposed to work. But after Artemis I, engineers noticed that instead of experiencing a gentle ablation, the heat shield was charred and had come off in chunks. There were even some holes in it.
This discovery directly led to the delay of Artemis II’s launch, which was previously scheduled for no earlier than September 2025. “Anytime you talk about fire, anytime you talk about entry and heat shields, you talk about parachutes, these are high risk things that don’t have fault tolerance built in,” Glover said at a press conference in August. “They have to work.”
To be sure: If the astronauts had been aboard Orion on Artemis I, they would have been absolutely fine. They wouldn’t have even noticed an increase in cabin temperatures. But because of NASA’s history with the Challenger and Columbia disasters, the agency’s safety culture demanded that researchers understand the root cause.
NASA finally did solve the problem after several months of hands-on testing of the Avcoat material, studying it in hypersonic wind tunnels and heating facilities.
Put succinctly, the heat shield’s ablative material was too impermeable, which led to internal pressure buildup during Artemis I’s unique re-entry path. Skip entry is a process that involves entering the atmosphere, lifting back out of it, and then re-entering, like a stone skipping across the surface of a pond. Artemis I was the first mission that attempted this maneuver; its main benefit is the ability to bleed off the tremendous speed involved from returning to Earth from the moon. It also allows Orion to travel further once entering the Earth’s atmosphere, which makes it easier to hit a pinpoint splashdown target. Between atmospheric skips, gases built up within the Avcoat material, which is what led to the heat shield cracking.
Artemis II Commander Reid Wiseman sits inside a spacecraft mockup during a training in Houston, Texas. Photograph by Mark Sowa, NASA/JSC
Mission specialist Christina Koch exits the Orion spacecraft mockup during a training. Photograph by Mark Sowa, NASA/JSC
Mission specialist Jeremy Hansen of the Canadian Space Agency sits in a boat following practice recovery procedures. Photograph by Isaac Watson, NASA
Artemis II Pilot Victor Glover sits inside an Orion spacecraft mockup during Post Insertion and Deorbit Preparation training. Photograph by Mark Sowa, NASA/JSC
After all the tests, NASA determined that Artemis II was safe to fly with its current heat shield, but NASA decided to use a modified “loft” trajectory rather than skip entry. Orion program manager Howard Hu says he is now “absolutely” confident that Artemis II’s heat shield will work as expected because of the reduced stress and re-entry heat.
But engineers had to work through other problems, too. Testing for Artemis II revealed that some of the batteries in the Orion capsule would not have been able to handle an abort scenario. And there were failures in some of the circuitry for valves on the capsule that necessitated a replacement.
These issues highlight why Artemis I and II are such important missions: They exist to troubleshoot problems that might arise during a future moon landing.
“These are test flights,” says Glaze. “I think that is so critical for people to understand that our first several flights are really testing and proving out the systems that we need in order to land our crew on the moon and then ultimately to on to Mars.”
Understanding what space travel does to astronauts on Artemis will be key for a future Mars mission
We don’t know exactly when Artemis II will launch. A flight like this is so dependent on everything going exactly as expected—from crew health to hardware and software performance to weather. It could lift off during the bright hours of the morning, or maybe like Artemis I, it will blaze into the sky during the dark of night.
But what happens after is set: After successful liftoff from Pad 39B in at Kennedy Space Center in Florida, the first stage of the massive SLS rocket will separate from the spacecraft. Orion will orbit the Earth twice, first in a lower 90-minute orbit and then it will move to a higher orbit, at which point it will jettison the second stage of the SLS rocket.
For almost 24 hours, Mission Control and the crew will check out Orion’s systems and make sure everything is working as expected—from life support to communications tests. After this is completed, the astronauts will conduct a burn of the main engine on Orion’s service module to set the spacecraft on a slingshot course around the moon.
It will take Artemis II approximately four days to reach the moon, and another four days to return home. During this time, the astronauts will continue to evaluate the spacecraft’s systems and practice emergency procedures.
Their bodies will also be put to the test to better understand the impacts of space exploration on them. “We consider the human one of the systems of the vehicle,” said Steven Platts, chief scientist of the Human Research Program, which is aimed at protecting the health of astronauts in space. “The most complex machine that’s going on the mission is the human. And we need to understand that system just as well as we understand any other system.”
Spaceflight can impact human health in myriad ways. Hand-eye coordination, spatial orientation, eyesight, bone density, and muscle mass can all diminish. Circadian rhythms can be interrupted, and the psychological effects of living in a small, isolated environment take their toll.
(RELATED: Here’s what we know about the toll spaceflight takes on astronaut health.)
Inside the Artemis Training Capsule at Johnson Space Center, 2023. Photograph by Dan Winters, Nat Geo Image Collection
Training capsule exterior photographed in Building 9 at Johnson Space Center, Houston, TX, 2023. Photograph by Dan Winters, Nat Geo Image Collection
The Orion capsule only has about 330 cubic feet of living space. That’s tiny: About the amount of cargo space in a sprinter van, and it’s going to house four astronauts who have to live, work, and sleep there for almost 10 days. That in and of itself is a science experiment: How will these astronauts cope with those close quarters?
“We have three different experiments on board that the astronauts will be participating in,” says Platts. (“All four astronauts signed up to do all three of our experiments,” Platts continues. “All human research is completely voluntary.”)
One of these is a series of surveys to determine psychological well-being and sleep patterns in this tight environment. It’s a constant concern for space travel, but since Artemis II is the first trip astronauts will take outside Earth orbit since 1972, this baseline data is extra important. NASA has been running simulations in closed environments here on Earth for years because they’ve long been interested in psychological implications of long-distance space travel, but Artemis II is a golden opportunity to get that data from space.
Two other experiments will assess how space changes the astronauts’ physiology. Scientists will take blood draws and wet saliva samples pre- and post-mission to examine biomarkers and hormones. During the flight, the astronauts will take dry saliva samples, which involves using a special blotting paper stored in a small booklet. Scientists can rehydrate the mission samples and compare them to the pre- and post-samples.
The crew will also perform an obstacle course before and after flight to assess the disturbances in astronauts’ balance control after a prolonged period in a microgravity environment, testing everything from hand-eye coordination to loss of steadiness. Platts is especially excited about this; it will be the first time the experiment is conducted with astronauts who have traveled outside of Earth orbit.
“The obstacle course will help mimic what it might be like when the crew has to egress a vehicle,” he explains. “This is looking forward to future lunar missions and even to Mars missions, when they have to get out of the vehicle on their own without the help of all this ground crew that we have here on Earth.” One of the issues Platts is specifically looking at is physical changes as astronauts move from Earth’s gravity to microgravity in space, and then onto the moon, which has one-sixth of Earth’s gravity. NASA knows what happens during that first transition, thanks to extensive experience in low Earth orbit. But these obstacle courses will provide a baseline for what comes next.
At their furthest, the Artemis II astronauts will travel between 5,000 and 9,000 nautical miles beyond the far side of the moon (the actual figure is dependent on the launch date), circling it in a figure eight on a free-return trajectory.
That distance is important—out there, astronauts are not as protected from radiation by the magnetic field of the Earth. Radiation exposure can increase the risk of cancer and other degenerative diseases. It may not be a problem for short flights, like Artemis II, but risks will increase in the future as missions to the moon, or even Mars, grow longer.
A technician works on an SLS’s avionics hardware at Marshall Space Flight Center in Huntsville, Alabama. Photograph by Dan Winters, Nat Geo Image Collection
“Artemis II will allow us to get some of the first human biological data from deep space radiation,” says Lisa Carnell, director for NASA’s Biological and Physical Sciences Division. “It’s the first time you can get data on healthy individuals and really understand what’s happening in a radiation environment.”
Alongside the astronauts, NASA is also stocking Artemis II with AVATARs (A Virtual Astronaut Tissue Analog Response), or specially made 3D human tissue chips the size of a USB drive. “It’s this mini replica of a human organ,” Carnell says.
(Related: How does cosmic radiation impact the body?)
These human tissue chips contain cell cultures that are specially grown to model the structure and function of specific parts of human organs. They can beat like a heart or breathe like lungs. “And we’re going to send them around with the crew to see what happens in the radiation environment,” explains Carnell. In specific, Artemis II will fly with AVATARs of bone marrow, which is extremely sensitive to radiation exposure.
Once they understand how an individual astronaut will respond to the rigors of deep space travel, in the future Carnell and her team will be able to create what she calls a “personalized medical kit” for each astronaut to help them counteract the effects of radiation. It’s just one way Artemis II will pave the way for Mars exploration.
What can humans do that cameras can’t? The eye for lunar color.
But the big highlight of Artemis II? Observing the lunar surface, of course.
The crew may be able to see parts of the moon humans haven’t experienced before; up to 60 percent of their far side view may be unique, Wiseman says. Compared to the Apollo missions, this crew will also see a more zoomed out view of the moon because their orbit will be much higher.
However, they’ll also only have three hours to make lunar observations. But Artemis II lunar science lead Kelsey Evans Young and her fellow scientist Noah Petro are packing as much scientific observations as they can into that brief time.
Petro is the project scientist for the Lunar Reconnaissance Orbiter (LRO), in addition to his work as a member of the Artemis science team. Launched in 2009, the LRO has been imaging the surface of the moon for over a decade, mapping its entire surface. But even so, he says, having human eyes look at the moon up close could give us important scientific insights.
The human eye can see subtle variations in color and texture that aren’t necessarily apparent on camera, and that’s just what Petro is hoping the astronauts will observe. “Each astronaut perceives the moon differently from one another. “Every human eyeball is different,” Petro says. “We have four crew members going on Artemis II. Each of them may detect color in a different way.”
The scientists aren’t expecting the Artemis II astronauts to make any major discoveries. Instead, they are hoping to use insights about how the astronauts perceive colors on the moon to help direct future explorers. “By getting well-trained human eyeballs to the moon… we have an opportunity to see things that we’ve missed,” says Petro. “No planetary scientist should ever think that we have a complete robust understanding of any planetary surface just because we’ve mapped it [robotically]. We have the data, but it’s up to the humans to interpret it.”
Artemis-I sits on the launch pad at Kennedy Space Center in September, 2022. The Artemis II astronauts will fly on a similar rocket. Photograph by Dan Winters, Nat Geo Image Collection
Why we’re going back: To understand ourselves and the universe
In 1968, Apollo 8 served a similar purpose as Artemis II. It was a test flight for the eventual Apollo 11 landing. Its astronauts were the first humans to ever orbit the moon. Jim Lovell, the pilot of that mission, and last surviving member of the crew, recently died in August. As Artemis II’s launch date approaches, Petro has been thinking about the legacy of that mission, and how much we’ve learned since.
Apollo 8 taught us how to send humans to the moon and bring them safely home. Lovell, Frank Borman, and William Anders were the first humans to see the far side of the moon. By describing what they saw, these astronauts set the stage for the lunar landings to come. This mission also brought us the famous Earthrise image, with the blue Earth rising above the gray, lifeless lunar surface, giving us an entirely new perspective of our place in the universe.
(Related: Everyone wants a piece of the moon—what could go wrong?)
There are still so many unanswered questions about the moon. The most profound ones are questions about our cosmic history. The moon’s surface is unchanging, which means by exploring the moon, scientists can start to understand what our own planet was like billions of years ago.
There’s more than just history, though. Scientists want to know if the moon’s shadowed polar craters indeed hold water ice. Or if lunar lava tubes are good places to build underground settlements, protected from radiation. There are numerous questions about lunar soil, called regolith: can vital resources be extracted from it, can it be used to build a sustainable outpost? NASA ultimately wants to learn how humans and survive, and even thrive, in outer space. And the moon is a teacher.
“As we know more, our questions increase but our ignorance increases as well,” says Petro. “We have so many assumptions that we know we’re going to be proven wrong on. And that’s why we go, right? If we knew everything about the moon, we would have no interest in going back.”