NASA is nearing its most consequential spaceflight in decades

That is the purpose of Artemis II.

The mission will carry four astronauts — Reid Wiseman, Victor Glover and Christina Koch from NASA, along with Canadian astronaut Jeremy Hansen — on a roughly 10-day journey that loops around the Moon and returns to Earth. The crew will not land, but they will travel farther from Earth than any humans in half a century.

Testing the unknown

Unlike Apollo, which relied on hardware that was rapidly developed and aggressively flown, Artemis is built on modern systems that have seen relatively little real-world use. The mission will test the Orion spacecraft, which must support astronauts in deep space, protect them from radiation, and survive a blisteringly hot reentry into Earth’s atmosphere.

The flight path itself is designed with caution in mind. Orion will slingshot around the Moon on a wide trajectory that allows the spacecraft to naturally fall back toward Earth even if its propulsion system fails — an added layer of safety NASA did not have during Apollo.

Still, the mission carries unavoidable risks.

“How do we handle the unknown?” Hansen said during a news conference last year. “That’s the most important thing we’re refining.”

Isolation beyond Earth’s protection

At its closest approach to the Moon, Artemis II will pass behind the lunar far side, cutting off communications with Earth for about 45 minutes. For astronaut Victor Glover, that moment underscores how exposed the crew will be.

“We’ll have a loss of signal,” he said. “It’s one of those times where you’re very aware that you’re on your own.”

Beyond communication gaps, the astronauts will also face a harsher radiation environment than those aboard the International Space Station. Low-Earth orbit remains partially shielded by Earth’s magnetic field. Artemis II will venture far beyond that protection.

NASA plans to collect extensive biological data during the flight, monitoring the crew’s sleep, cognition, stress levels, immune response and cardiovascular health. Small samples of human tissue will also fly aboard to help researchers understand how the human body responds to deep space.

“The science of Artemis is the science of us,” said Jacob Bleacher, NASA’s chief exploration scientist.

Hardware under scrutiny

The mission will launch aboard NASA’s massive Space Launch System from Kennedy Space Center. Both Orion and SLS flew successfully during the uncrewed Artemis I mission in 2022 — but Artemis II will be their first true test with humans on board.

One component has drawn particular scrutiny: Orion’s heat shield. During Artemis I, the shield showed unexpected wear as the capsule reentered Earth’s atmosphere at speeds exceeding 25,000 miles per hour. While the damage did not endanger the mission, NASA spent more than a year analysing and addressing the issue.

Agency officials say they are confident the heat shield can safely carry a crew home.

A steppingstone to the Moon — and beyond

Artemis II is not an end goal. It is a proving ground.

If successful, it will pave the way for Artemis III, which aims to land astronauts near the Moon’s south pole later this decade — a region thought to contain water ice and critical resources for long-term exploration.

The mission also unfolds against a geopolitical backdrop. US lawmakers increasingly frame lunar exploration as a strategic imperative as China advances its own Moon ambitions.

For now, however, the focus is simpler: get there, and get back.

Even mistakes, Glover has said, would carry value. “They would be data points,” he noted, “that show what humans can do when we work together on something difficult.”

For NASA, Artemis II represents something rarer than a technological milestone. It is a chance to prove that, after decades of starts and stops, humanity is once again ready to leave Earth behind.