Artemis II to surpass Apollo 13 record for farthest humans in space

• The Artemis II mission marks the first time humans have approached the moon in over 50 years.
• Astronauts will travel farther from Earth than any human has before, breaking a record set by Apollo 13.
• The crew will observe the far side of the moon, including being the first humans to see the Orientale basin with the naked eye.
• During the lunar flyby, the crew will experience a planned 40-minute communications blackout while behind the moon.
• The mission will pave the way for future lunar landings by collecting vital data and photographs.

The crew members of NASA's Artemis II mission are about to make spaceflight history as they approach the moon for the first time in more than half-a-century.

Since the Apollo era ended in 1972, no human has ever left Earth orbit, let alone ventured all the way to our celestial neighbor.

Now, that's hours away from changing.

The four astronauts selected for the trailblazing Artemis II mission have already left Earth's orbit behind. Up next, they'll have a close-up rendezvous with the moon while simultaneously traveling farther in space than humans have ever gone.

For about seven hours on Monday, April 6, the main cabin windows of the Orion spacecraft the astronauts are aboard will be pointed toward the moon to allow the crew members to witness lunar sights no human ever has.

The data the astronauts collect and the photographs they capture could prove vital as NASA uses the test flight to pave the way for humans to return to the surface of the moon as early as 2028.

Here's everything to expect during Artemis II's lunar flyby.

Artemis II astronauts to travel farthest from Earth than anyone else

The Artemis II astronauts are expected to make spaceflight history when they travel farther in space than any human has ever been.

Just before 2 p.m. ET, the Orion spacecraft carrying the four-person crew is due to surpass a record set in 1970 when the astronauts on the infamous Apollo 13 mission reached 248,655 miles from Earth while making an emergency return. From there, the Artemis II astronauts will go a another 4,102 miles farther – reaching by around 7 p.m. an expected maximum distance of 252,760 miles from Earth, according to NASA.

Artemis II crew to see moon's far side during historic lunar flyby

The moon's far side, often colloquially referred to as the "dark side of the moon," is the hemisphere that is never visible to us on Earth due to the way the moon mirrors its rotation on its axis as it orbits our planet.

Swooping around the far side of the moon, the Artemis II astronauts aboard Orion will come no closer than about 4,070 miles above the surface.

At that distance, the astronauts will be at a much higher altitude than the approximately 70 miles high at which the Apollo missions soared. That means the crew of Artemis II will be able to witness sights of the moon's far side that no human has ever laid eyes upon – at least in person.

From that vantage, our celestial neighbor will appear to the astronauts to be about the size of a basketball held at arm’s length, allowing them to see the entire disk of the moon, including its poles, NASA explained.

They'll have nearly seven hours to make observations and collect data for scientists back on Earth – and with 30 targets to observe, they'll need all the time available.

As they whizz around the moon, the crew members will photograph and describe lunar features such as impact craters, ancient lava flows, and surface cracks and ridges that formed as the moon slowly changed over time.

Astronauts to be 1st to observe Orientale basin

One of the most prominent features the Artemis II astronauts will observe is a prominent crater known as the Orientale basin.

Spanning nearly 600 miles, the distinctive crater straddles the moon’s near and far sides, according to NASA. Formed 3.8 billion years ago when a large object struck the lunar surface, the crater to this day retains "dramatic topography" resulting from that impact, according to NASA.

During the flyby period, the Orientale basin will be fully illuminated and visible, making the Artemis II astronauts the first humans to see it with the naked eye.

Astronauts to lose contact with Earth for 40 minutes

The Artemis II crew will experience a planned – but still tense – period of radio silence when they briefly lose contact with Earth.

Expected to last about 40 minutes beginning at 6:44 p.m. ET, the communications blackout will occur as the Orion spacecraft travels behind the moon, blocking its signal from reaching NASA's Deep Space Network. The array of giant radio network antennas on Earth is responsible for maintaining communications with the Artemis II astronauts aboard Orion.

Such blackouts are expected and have also occurred during the Artemis I and Apollo missions, according to NASA. Once Orion reemerges from behind the moon, the Deep Space Network should be able to quickly reacquire the vehicle's signal and restore contact between it and mission control at the Johnson Space Center in Houston, Texas.

Astronauts to witness solar eclipse from aboard Orion spacecraft

One of the later additions to the astronauts' "lunar targeting plan" includes witnessing a total solar eclipse.

As the moon and sun align in a precise way with the Orion capsule, our star will disappear behind the moon for about an hour. During the eclipse, taking place near the end of the observation period, the crew will have about an hour to observe a mostly dark moon and analyze the sun's elusive outermost layer, known as the corona.

The crew also will look for flashes of light from any meteoroids that strike the surface to gather insight on potential surface hazards, NASA added.

Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at [email protected]