Humans are on course to live on the moon before the end of the decade, a NASA official has said.
Howard Hu, the head of the agency’s Orion lunar spacecraft programme, told the BBC that humans would "certainly" be active on the moon for “durations” before 2030.
"They will be living and have habitats and they will have rovers on the ground, that's what we're also working on," Mr Hu told the Sunday with Laura Kuenssberg programme
"We're going to be sending people to the surface, they're going to be living on that surface and doing science."
Mr Hu spoke as a NASA space capsule hurtled toward the moon for the first time in 50 years.
Artemis 1, the most powerful rocket in history, took off on Wednesday in a dress rehearsal for astronaut flights.
After years of delays and billions in cost overruns, Artemis thundered skyward, rising from Kennedy Space Centre on 8.8 million pounds of thrust and hitting 100 mph within seconds.
The Orion capsule was perched on top, ready to burst out of Earth's orbit toward the moon not quite two hours into the flight.
Mr Hu called the launch a "historic day" for human space flight.
"It's the first step we're taking to long-term deep space exploration, for not just the United States but for the world," he said.
"And I think this is an historic day for Nasa, but it's also an historic day for all the people who love human space flight and deep space exploration.
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"I mean, we are going back to the Moon, we're working towards a sustainable programme and this is the vehicle that will carry the people that will land us back on the Moon again."
One of NASA's long term ambition is to go to Mars, Mr Hu added.
"It's really going to be very important for us to learn a little bit beyond our Earth's orbit and then do a big step when we go to Mars," he said.
"And the Artemis missions enable us to have a sustainable platform and transportation system that allows us to learn how to operate in that deep space environment."
The Orion capsule is due back on Earth in December. US government watchdogs estimate NASA will have spent $93 billion (£78bn) on the project by 2025.