Humans could be living on the Moon during this decade, according to a NASA official.
Howard Hu, who oversees the Orion lunar spacecraft programme for the agency, said humans could be staying there for extended durations, in an interview to the BBC.
"Well, certainly in this decade we're going to have people living there," Mr Hu told BBC's Sunday with Laura Kuenssberg show.
"They will have habitats and rovers on the ground, that's what we're also working on at NASA."
Humans last walked on the Moon in 1972
Ultimately, when it comes to people being sent to the Moon, the mission is really about science, Mr Hu added.
"That's what we're going to be doing, we're going to be sending people down to the [Moon's] surface and they're going to be living on that surface and doing science."
NASA's spacecraft Artemis launched towards the Moon on its first uncrewed mission last week.
Orion is currently about 28,864 miles (46,452 kilometres) from the Moon as of Monday morning 11:30 AEDT.
After a series of delayed attempts, NASA's moon megarocket blasted off from Cape Canaveral on its 25-day mission.
Over the course of the mission, it will travel 280,000 miles (450,000 kilometres) from Earth and 40,000 miles (64,000 kilometres) beyond the far side of the Moon.
NASA says this first Artemis mission will demonstrate the performance of both Orion and the Space Launch System (SLS) rocket, and pave the way for future missions, including landing the first woman and first person of colour on the Moon's surface.
Orion is the vehicle that will take astronauts on Artemis missions. NASA says it's the only spacecraft capable of human deep space missions and high-speed return to Earth.
Orion will fly-by the Moon tonight
The Orion spacecraft will do a fly-by of the moon on Monday, November 21.
NASA expects the rocket's closest approach of approximately 80 miles (129 kilometres) from the Moon's surface at 7:57 a.m EST, around midnight Australian Eastern Daylight Time (11:57pm AEDT).
Orion will lose communication with Earth as it passes behind the Moon from 7:25am through 7:59am EST (11:25pm AEDT through to 11:59pm AEDT).
Live coverage will start at 7:15am EST (11:15pm AEDT) on NASA TV.
So far, Orion had travelled 233,613 miles (375,963 kilometres) from Earth by Monday morning at 11.30am AEDT, cruising at 249 miles per hour.
Named after the ancient Greek goddess of the hunt — and Apollo's twin sister — Artemis aims to return astronauts to the Moon as early as 2025.
Stepping stone to Mars
NASA's long-term plan is to establish a "sustainable presence" on the Moon in preparation for missions to Mars.
"Moving forward is really to Mars. That is a bigger stepping stone, a two-year journey depending on the orbit you take," Mr Hu told the BBC.
"These are the stepping stones that hopefully will allow this future capability … and give those opportunities and option for our kids and their grandkids and their kids."
NASA hopes to send four astronauts around the Moon on the next flight, in 2024, and land humans there as early as 2025.
