NASA is moving ahead with plans to send astronauts back to the moon by 2024, awarding a $375 million contract to commercially develop the first module for a mini space station in lunar orbit that will serve as a staging base for astronauts descending to the surface, the agency announced Thursday

Speaking at the Florida Institute of Technology in Melbourne, Florida, NASA Administrator Jim Bridenstine also said NASA planners expect to select a core group of astronauts, perhaps about a dozen or so, as early as this summer to begin generic training for the accelerated Artemis moon program.

"As far as the astronaut selection for who is going to be the first woman or the next man on the surface of the moon, if we have a two-person lander it could be two women," Bridenstine told reporters. "We don't know, we haven't picked yet.

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"But in the coming months, we're going to put together a cadre of people that we will select from for those lunar activities. Down at the Johnson Space Center, there's already a list. And I'll also tell you that at NASA in general, every single one of our astronauts, they want to be that person."

An artist's impression of the Gateway lunar landing staging base in orbit around the moon. NASA

He said the first astronauts to walk on the moon in the Artemis program will only spend a few hours on the surface, much like Neil Armstrong and Buzz Aldrin did during the pioneering Apollo 11 mission 50 years ago this summer.

"It would not be days," he said of the initial Artemis mission. "We will be able to get out of the (lander), walk around on the surface of the moon, do meaningful science, leave experiments, gather rocks or regolith and then get back on the spacecraft and head back to the Gateway."

The goal, he said, is to "prove out all of the capability with our best test astronauts and then eventually, future missions after that, we would have potentially habitation capability with longer duration missions."

Until recently, NASA was working on plans to return astronauts to the moon by 2028. But the Trump administration has directed the agency to move that schedule up by four years, setting 2024 as the new target date.

To help kick start the recently named Artemis program, the administration is asking lawmakers for an additional $1.6 billion for NASA in the agency's amended 2020 budget request to fund the rapid development of critical systems needed to turn that 2024 target into reality. Additional funding will be needed in subsequent budgets.

Some of that initial seed money is earmarked for ongoing development of the Space Launch System super rocket Boeing is developing for NASA to boost astronauts to the moon in Lockheed Martin-built Orion capsules. An initial unpiloted test flight is planned for late next year, followed by the first piloted test flight in 2023.

The third flight of the SLS will carry astronauts to the moon for a landing in 2024. By that point, a small space station, known as Gateway, must be in orbit around the moon, along with a landing vehicle of some sort to carry the Orion crew to the moon's surface. NASA expects to award contracts for the lander by around Oct. 1.

The core of the Gateway station is a power and propulsion module equipped with a high-tech 50-kilowatt solar electric propulsion system and large solar arrays to provide the necessary power. It will weigh about 11,000 pounds at launch, half of that propellant.

A small pressurized module will be attached providing at least two docking ports, one to accommodate visiting Orion capsules and the other for use by the lunar lander and ascent vehicle.

A NASA chart showing notional plans for the Gateway lunar space station. NASA

NASA selected Maxar Technologies for Gateway's power and propulsion element over competing proposals from Boeing, Lockheed Martin, Northrop Grumman and Sierra Nevada.

The fixed price contract announced Thursday has a maximum value of $375 million. The contract begins with a 12-month base period covering the module's design followed by options covering development, launch in late 2022 and a flight demonstration lasting as long as one year.

During that period, the spacecraft, launched atop a commercial rocket, will be owned and operated by Maxar. If all goes well, NASA will buy the spacecraft to serve as the core element of the Gateway station.

"This program will not only achieve NASA's goals, but will be transformational for the private sector, creating jobs and innovation along the way," said Mike Gold, Maxar vice president for civil space.

Bill Gerstenmaier, director of space operations at NASA Headquarters, said the contract award marked a significant milestone for the Artemis program.

"This is a major thing to have a partner on contract with us to go deliver this first key piece of the Gateway, which will be critical to us, establishing this unique piece of infrastructure around the moon," he said.

"There's a lot of hard work in front of us, it's not going to be easy putting all the hardware together to get ready to go towards the moon, but this is a key first step, a key enabler."

The power-and-propulsion module's fuel-efficient engine will be able to change Gateway's orbit, giving astronauts the ability to reach virtually any target on the surface. In the near term, the target is the moon's south polar region where large reservoirs of ice are present in cold, permanently shadowed craters.

Finding accessible ice deposits would allow future crews to use solar-powered electrolysis to extract hydrogen and oxygen, providing an in situ source of rocket propellants, air and water.