What is Artemis 2? What to know about NASA's historic moon launch

Yes, robotic U.S. landers have begun to touch down on the moon in recent years. But ever since the Apollo era came to an end in 1972, humans have yet to venture back anywhere near Earth's celestial neighbor.

Now, that's due to change with the launch of a NASA mission known as Artemis 2.

The second under the U.S. space agency's multibillion-dollar Artemis program, the mission is also the first in the renewed lunar campaign with a crew. While those crew members won't be making a lunar landing, their 10-day journey around the moon and back will pave the way for NASA to put boots back on the surface in the years ahead.

Ahead of the Artemis 2 launch, here's everything you need to know about the mission.

When is the Artemis II launch?

NASA is working toward an April 1 launch of the Artemis II mission, with a two-hour launch window opening at 6:24 p.m. ET. If bad weather or any other issues arise before liftoff, NASA has also announced other launch opportunities available April 2-6 and again April 30.

The long-awaited mission was originally slated for February before hydrogen fuel leaks and, more recently, helium flow issues on NASA's towering 322-foot Space Launch System rocket prompted a series of delays.

What is the Artemis 2 mission?

Though no lunar landing is in store, the Artemis 2 mission will send a crew of four astronauts on a historic 10-day journey around the moon to test systems and hardware for future expeditions to the surface.

The mission will also make history, with the astronauts traveling farther from Earth than any human has ever been in space. While traveling up to 6,000 miles above the lunar surface, the astronauts will see parts of the far side of the moon that not even the Apollo astronauts witnessed.

At that distance, the moon will appear to the crew to be about the size of a basketball held at arm’s length, according to NASA.

What was the first Artemis mission?

The mission would come more than three years after Artemis 1 launched Nov. 16, 2022, from the Kennedy Space Center, sending the Orion capsule on a moon-orbiting mission without a crew in the first test of the vehicle. The Orion splashed down Dec. 11, 2022, in the Pacific Ocean.

What is the Space Launch System rocket?

The rocket that will provide the initial burst of thrust at liftoff to send the astronauts on their way is known as the Space Launch System, built by Boeing and Northrop Grumman.

Towering at 322 feet tall, the SLS rocket isn't quite as tall as the retired 363-foot Saturn V used during the Apollo era, but it's much more powerful. In fact, the 8.8 million pounds of thrust it generates at liftoff is more than 15% more power than Saturn V's capability, making it the most powerful spacecraft NASA has ever launched.

The SLS rocket is composed of a 212-foot core stage propelled by four engines powered by a mix of liquid hydrogen and liquid oxygen, as well as two 177-foot-tall solid rocket boosters mounted to the sides, providing the bulk of the thrust — a measure of the amount of force used to push the vehicle off the ground.

What is the Orion capsule?

The astronauts themselves will be aboard an Orion crew capsule — built by Lockheed Martin — which will hitch a ride to orbit atop the SLS rocket. The crew module portion of the 26-foot-tall spacecraft is just 11 feet high and 16 1/2 feet wide, but it offers plenty of amenities and state-of-the-art protection from the hazards of space travel, including a stowage locker that would shelter the crew from solar radiation.

It's from Orion's windows that the astronauts will glimpse an unprecedented view of Earth and the moon — with our planet being up to nearly a quarter-million miles away, according to NASA.

Artemis missions to launch from Kennedy Space Center in Florida

All of NASA's Artemis missions will get off the ground from the Kennedy Space Center in Cape Canaveral, located along Florida's Atlantic coast.

At the Kennedy Space Center, perhaps no launch site is more iconic than Launch Complex 39A, where the majority of NASA's Apollo moon missions got off the ground — including the groundbreaking Apollo 11 moon landing.

But because SpaceX has construction underway at 39A ahead of a highly-anticipated Florida debut of Starship, the launch pad has been closed for weeks. That means the Artemis 2 mission will instead lift off a little further north from the less-prolific Launch Complex 39B — the site of one Saturn V launch on the Apollo 10 mission in 1969.

Moon landing planned for 2028. What to know about Artemis 3, 4

NASA's ultimate objective in the years ahead is to use a series of both uncrewed and human lunar landings to set up a permanent moon base on the south pole.

A moon landing is now due to take place as early as 2028 during a mission known as Artemis 4.

Prior to that mission, Artemis 3 astronauts aboard the Orion capsule are due to meet and dock in 2027 in Earth orbit with at least one of the commercial lunar landers being developed by Elon Musk's SpaceX and Jeff Bezos' Blue Origin. NASA will also use the mission to test space suits, known as extravehicular activity suits, being developed by Axiom Space for astronauts on the lunar surface.

After the Artemis 5 mission, NASA Administrator Jared Isaacman has said the agency wants to target a human lunar landing up to twice a year — if not more often.

Why does NASA want to land on the moon?

The moon's largely unexplored south pole is where water ice is thought to be abundant, which could be extracted and used for drinking, breathing and as a source of hydrogen and oxygen for rocket fuel.

From there, the first astronauts could embark on voyages to Mars.

When was the least time Americans were on the moon? What to know about Apollo

The last U.S. astronaut to land on the moon was on Dec. 19, 1972, during NASA's Apollo 17 mission. All told, NASA astronauts have been to the moon on six separate Apollo missions, beginning with Apollo 11 in 1969.

But Artemis 2 most closely resembles a mission known as Artemis 8, which on Dec. 21, 1968, sent three NASA astronauts on a six-day trip orbiting the moon. As a prelude to a lunar landing, the flight was an important step in testing the flight trajectory and operations before astronauts set foot on the moon's surface.

Who are the astronauts on the Artemis 2 mission?

The four crew members of Artemis 2 arrived in Florida on March 27 after entering standard preflight quarantine to avoid illnesses. Here's a look:

• NASA astronaut Reid Wiseman, a Baltimore native and the mission's commander, last flew to space in 2014 on a Russian Soyuz rocket to the International Space Station.
• NASA astronaut Victor Glover, the pilot from Pomona, California, flew to space in 2020 on a SpaceX mission to the space station.
• NASA astronaut Christina Koch, a mission specialist from Grand Rapids, Michigan, who holds several space agency records and flew in 2019 on a Soyuz ISS mission.
• Canadian Space Agency astronaut Jeremy Hansen, another mission specialist who will fly to space for the first time.

Glover is due to become the first Black astronaut to travel near the moon, while Koch will become the first woman to do so, Reuters reported. Additionally, Hansen is set to become the first Canadian to fly close to the moon.

When, where will the astronauts return to Earth?

The planned trajectory for the four-day return journey will use Earth's gravity to naturally pull Orion back home after flying by the moon, negating the need for propulsion or much fuel.

Once Orion blazes through Earth's atmosphere, a protective shield will be cast off to make way for parachutes to deploy and slow it down. The capsule will then make a water landing in the Pacific Ocean near California, after which five orange airbags will inflate around the top of the spacecraft and flip the capsule into an upright position to allow the crew to exit.