'We are getting very, very close': NASA makes final Artemis II preparations as expectation grows for Wednesday launch

NASA is making its final preparations to launch its Artemis II rocket on a historic crewed flight around the moon.

Artemis II's mission management team will make a final decision about the readiness of its Space Launch System (SLS) and Orion capsule to launch this afternoon. If they give the green light, then Artemis II could take off during a two-hour launch window that opens at 6.24 p.m. ET on Wednesday (April 1).

The space agency has said there's an 80% chance of favorable weather conditions to launch Artemis II on Wednesday. NASA is mainly concerned with cloud cover and the potential for high winds above the launch site at the Kennedy Space Center in Florida.

"We are getting very, very close, and we are ready," Lori Glaze, the acting associate administrator for NASA's exploration systems development mission directorate, said during a news conference on Sunday (March 29).

Artemis II is scheduled to take humans farther into space than ever before as part of a 10-day test flight around the far side of the moon. This is NASA's first attempt to send humans back to the moon in more than 50 years, with hopes it will pave the way for lunar landings in 2028 and future crewed missions to Mars.

The Artemis II crew includes three NASA astronauts: commander Reid Wiseman, pilot Victor Glover, and mission specialist Christina Koch, along with Canadian Space Agency astronaut and mission specialist Jeremy Hansen.

On Sunday, the crew took virtual questions from the press at their quarantine quarters at Kennedy Space Center (astronauts go into quarantine ahead of a launch to ensure they don't get infected by illnesses that could delay their mission). Commander Wiseman stressed that the mission is a test flight, and the crew doesn't have an expectation that they will fly on Wednesday.

"This is the first time we're going to try this," Wiseman said. "This is the first time we're loading humans on board. And I will tell you, the four of us, we are ready to go, the team is ready to go and the vehicle is ready to go, but not for one second do we have an expectation that we are going."

"We will go when this vehicle tells us it's ready, when the team is ready to go," he added."So, we might go out to the pad and we might have to try again a few more times and we are 100% ready for that."

NASA has worked through numerous issues and delays to get to this point. For example, last month, the mission was delayed for the second time this year after NASA discovered a helium-flow issue in the upper stage of the mission's Space Launch System (SLS) rocket. NASA said it has fixed that problem, but that doesn't mean new problems won't arise to delay the mission again between now and Wednesday.

The April launch windows for Artemis II run from Wednesday through to Monday (April 4 to 9), with the potential for a launch on any of those days. After Monday, the next launch window is April 30. This will be NASA's last chance to launch the rocket on time, as the mission is meant to lift off no later than April 30.