Nasa has released details of robotic landers, hopping drones and vehicles it aims to send to the Moon as part of US plans to build a lunar base.
Amazon founder Jeff Bezos's space company Blue Origin is one of several companies picked to build the machines.
The US wants to land Americans back on the Moon before President Donald Trump leaves office in 2028.
But Nasa is competing with China to returns humans to the lunar surface, meaning the space agency is under pressure to appear to be winning the new space race.
China is forging ahead with its own plans to land humans on the Moon by 2030.
On Monday it launched its Shenzhou-23 spacecraft, sending a crew of astronauts to the country's Tiangong space station.
In March, Nasa announced a $20 billion programme to construct a permanent base powered by nuclear and solar energy at the Moon's south pole by 2032.
Nasa administratorJared Isaacman said on Tuesday that the announcements mean the US will "never give up the Moon again".
A base would allow the US to carry out scientific experiments, potentially mine valuable resources, and travel to Mars more easily.
But most experts agree that Nasa's timeline is unrealistic.
Despite the US's success in sending four astronauts around the Moon in its Artemis II mission in April, some scientists believe China is likely to be the next country to land humans on the lunar surface.
"It would not surprise me at all if China gets there first," Dr Simeon Barber, Lunar Scientist at Open University, told BBC News, citing Nasa's setbacks in securing a craft that can land humans on the Moon.
Nasa's Ignition Moon Base programme has three phases.
Before humans travel there, the space agency wants to send robotic landers and hopping drones to explore and map the Moon's challenging terrain.
Delivery vehicles would also be taken that could drive astronauts over the lunar surface and carry communications and scientific instruments.
On Tuesday, Nasa said companies including Blue Origin, Intuitive Machines, and Astrobotic have been awarded the contracts to build the machines.
Nasa wants Blue Origin's lunar lander, called Endurance, to be able to carry out precise landings, as well as autonomous navigation and control.
Astrobotic's Griffin-1 lander is expected to land at Nobile Crater near the South Pole.
The machines will also deliver scientific instruments for Nasa, including high-resolution cameras and tools that use reflected laser light to help the craft land.
This robotic exploration should last until 2029, with 25 launches and 4 metric tonnes of cargo landed on the Moon, Carlos García-Galán, Moon Base programme executive said on Tuesday.
Next, Nasa wants to build nuclear and solar power facilities on the Moon, including fission reactors.
By 2032, the space agency wants humans to be able to live on the Moon in "semi-permanent" housing.
Rovers would also enable astronauts to travel long-distance across the rocky surface.
The Moon's South Pole is particularly appealing because frozen water could be used for drinking water or to produce oxygen.
However, Nasa's plans rely on a spacecraft being ready that can safely transport humans to the Moon.
Elon Musk's company SpaceX is contracted to build a craft called Starship Human Landing System, but it has faced numerous setbacks and delays.
"The limiting step is getting the astronauts down onto the surface," explains lunar scientist Simeon Barber.
"It sounds to me like [Nasa] feel they're in a position where they have to start saying they've got plans. So I think there's a lot of political drive behind this," he says.
