KENNEDY SPACE CENTER — While the puzzle pieces have been laid out over the last two years, a picture is beginning to form for NASA’s pursuit of the first human spaceflight of its Artemis program to the moon.

While the launch of Artemis II is still officially more than 16 months away, its massive Space Launch System rocket core stage went vertical inside KSC’s cavernous Vehicle Assembly Building this week while the four crew set to be the first to fly to the moon in more than half a century say they’re ready to go.

Amid the clanging echoes of work in progress across the building that spans eight acres, the three NASA and one Canadian Space Agency astronauts were on hand to let everyone know they’re on board with NASA’s decision to move forward without replacing the heat shield on their ride to the moon, the Orion space capsule.

“My wife, when the announcement was made, she looked at me and she said, ‘Well, what do you think?’ I said, ‘I think it’s safe and I think it’s go time,” said NASA’s Victor Glover, the pilot for the mission. “I always tell my family, don’t pay attention to launch dates until I tell you to do so. And this is the first one — you know, there have been several since we’ve been assigned to this mission — and this is the first one I said, ‘Hey, put it on your calendar and and be ready.’”

Targeting no later than April 2026, the quartet of Glover, commander Reid Wiseman, NASA’s Christina Koch and the CSA’s Jeremy Hansen would be the first humans to fly to the moon — although not land on it — since the last Apollo mission in December 1972. The test flight would pave the way for the Artemis III mission that looks to return humans to the surface, including the first woman, by mid-2027.

Artemis flights launch on the Space Launch System rocket, which is a core stage made by Boeing powered by refurbished space shuttle-era RS-25 engines from L3Harris’ Aerojet Rocketdyne. Those combine with solid rocket boosters by Northrop Grumman to provide 8.8 million pounds of thrust on liftoff to send the Lockheed Martin-built Orion spacecraft on its way to the moon.

The Artemis I flight in 2022 was considered a win for the SLS rocket, which while delayed and over budget, remains the most powerful rocket to ever launch a payload into orbit.

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But the return of Orion, which hurtled back to Earth at close to 25,000 mph facing reentry temperatures of near 5,000 degrees Fahrenheit, gave NASA and Lockheed a major hurdle to solve. The heat shield suffered more than 100 cracks and chunks that posed a danger to humans if flown again in the same way.

NASA announced in October it had been able to recreate the problem on Earth, but only announced last week its plan to stick with the heat shield for Artemis II and just adjust the return flight trajectory as a safe solution.

“From a safety perspective, I think it’s been proven through our data, through our testing and all the analysis we did to show that we have a safe way to fly the heat shield that we have today,” said Howard Hu, NASA’s Orion program manager.

It’s a decision that still delays the launch for about eight months, although that would have likely been closer to two years had NASA opted to replace the heat shield.

With that decision in place, the machine of getting the SLS rocket and Orion spacecraft ready for launch have already begun moving.

With the core stage standing upright for the first time, the two solid rocket boosters will begin to be pieced together as soon as this week while the Orion spacecraft is expected to arrive to the VAB by April or May, said Amit Kshatriya, deputy associate administrator of NASA’s Moon to Mars Program Office.

“The full integrated stack we’re going to try and roll by the end of 2025,” Kshatriya said.

Then the rocket heads to KSC’s Launch Pad 39-B for more tests and could be ready for launch even earlier than April 2026, he said.

“We said ‘no later than’ because we meant ‘no later,’” Kshatriya said. “I believe we have taken a lot of the risk out of the integration flow here, out up front, because of the time we’ve been working on getting the development activity done for (Artemis) II, so I think it’s very realistic.”

Kshatriya adds that the change in return trajectory for Orion means chances for launch each month will be more limited than the windows  under which NASA was able to launch Artemis I. Those chances will become even tighter for Artemis III because that mission will require Orion to rendezvous with a version of SpaceX’s in-development Starship in orbit.

“I want to set a date earlier than April because I want to challenge this team to do that,” he said. “We have got to get our launch probability up. It’s going to be very difficult to launch this vehicle, given the constraints that we put on it.”

He’s realistic, though, that not everything will go as planned.

“Are we going to run into problems? Of course we are. That’s just the name of this business. I mean, if you look at the size and scale of the machine behind me, and then all the other parts that have to come together, absolutely, but I think that this team can do it.”

Despite the eight-month delay, there is a sense of urgency among NASA and its prime contractors for the program, especially with the specter of a new Trump administration that may opt for changes in the Artemis program.

“Every administration wants to put their stamp on the government,” said Kirk Shireman, a former NASA executive who’s now a Lockheed Martin vice president and program manager for Orion. “Things change, and just from a pure practical sense —building spaceflight — I don’t care who you are, what country you’re from, it takes a long time, and so we need this. We need to keep on that path to complete what we started. That’s the most efficient way.”

So he’s in favor of sticking with SLS under the current plan.

“At this point in time, SLS is really the only game in town,” he said. “This is the only rocket right now that can do this job.”

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Trump’s nominee to head NASA is billionaire Jared Isaacman, who flew to space twice with SpaceX, whose founder Elon Musk is set to be part of a new Department of Government Efficiency that could take parts of the Artemis program to task.

NASA’s Office of the Inspector General in an audit last year stated that through 2025, Artemis missions would have topped $93 billion. That includes billions more than the original costs projected when the program was announced in 2012 as well as years-long delays seen to the SLS, Orion, a future mobile launcher and other needed facets such as SpaceX’s Starship for the human landing system and new spacesuits from Axiom Space.

“We’re not married necessarily to the mission design that was written down five years ago,” Kshatriya said. “We know that’s going to evolve with elements and how they perform.”

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That means NASA is open to change, but looking at each launch as an individual goal, and not seeing the overall program objectives could be limiting.

“When you see the rocket flight, people love that. It’s incredible. It inspires everybody,” he said. “But the reality is, there’s like 50 different integrated test activities that have to happen in the next four or five years in order to get to our goals.”

He expects Isaacman, if approved by the Senate, will be open-minded, and the chatter from critics of SLS that want some sort of shift to Starship or another heavy-lift rocket like Blue Origin’s New Glenn for future launches, is a decision that cannot be made without more data.

“We’re constantly evaluating different options for how to do the missions.” noting a big challenge is that Orion’s size in itself means switching launch vehicles would bring different risks, and more delays. “We want to to get to the objective, which I think this administration is going to want very clearly, which is to make sure we do those landings as soon as we can.”