WASHINGTON — The White House and NASA announced May 13 that they will seek an additional $1.6 billion in funding for the agency in fiscal year 2020, a “down payment” on efforts to achieve a human lunar landing by 2024.

In a tweet late in the day, President Trump announced the additional funding to support a return to the Moon and later missions to Mars. “I am updating my budget to include an additional $1.6 billion so that we can return to Space in a BIG WAY!” he wrote.

Under my Administration, we are restoring @NASA to greatness and we are going back to the Moon, then Mars. I am updating my budget to include an additional $1.6 billion so that we can return to Space in a BIG WAY! — Donald J. Trump (@realDonaldTrump) May 13, 2019

NASA shortly thereafter published a summary of its budget amendment, which calls for nearly $1.9 billion in new funding for developing lunar landers and accelerating work on the Space Launch System and Orion. It would also go towards exploration technology development and additional science missions to the moon. That increase would be offset by cutting funding for the lunar Gateway by $321 million, reflecting the agency’s plan for only a “minimal” Gateway needed to support a 2024 landing.

“This additional investment, I want to be clear, is a down payment on NASA’s efforts to land humans on the moon by 2024,” NASA Administrator Jim Bridenstine said in a call with reporters announced on a little more than an hour’s notice that evening. “This is a good amount that gets us out of the gate in a very strong fashion, and sets us up for success in the future.”

Of that additional funding, $1 billion would go to lunar lander development, specifically an “integrated commercial lunar lander” whose development would be led by industry. Bill Gerstenmaier, NASA associate administrator for human exploration and operations, said on the call that approach would give companies more flexibility in making trades in the overall design of the lander, rather than separately contract individual components like the ascent and descent stages.

“If we’re going to be there in 2024, we’ve got to spend roughly about a billion dollars in 2020 to get that activity moving forward,” he said of lunar lander development. “There’s long-lead items, there’s hardware, there’s pieces we need to move in place, and now’s the time to go move.”

Most of the rest— $651 million — would go to SLS and Orion “to make sure they stay on track,” Gerstenmaier said. The request didn’t specify how the additional funding would support those two programs, but Bridenstine emphasized in the call that the heavy-lift rocket and crewed spacecraft, along with its European-built service module, are together “an absolutely critical piece of the architecture.”

In the call, Bridenstine and others emphasized that, other than the cut in proposed Gateway funding, no other NASA programs were reduced to support this funding increase. However, the $1.6 billion in additional funding is likely to be offset elsewhere in the overall federal budget, as part of a revised budget expected to be delivered to Congress by the White House’s Office of Management and Budget by May 14. Bridenstine said he was unaware of what those offsets might be.

Bridenstine also said that the $1.6 billion in additional funding was in line with what the agency requested of the White House, despite reports that NASA sought much more money. “We told the White House, and we told OMB, how much money it would take in the year 2020 to get us out of the gate for a landing on the moon in 2024,” he said. “They responded with what we requested, and we’re very proud of that.”

He declined to estimate how much more money NASA would need in 2021 through 2024 to enable that 2024 landing. “We expect in future years that it will be more than the current $1.6 billion for 2020. We all know that,” he said. “We are working day in and day out to come up with what those numbers are for the future years.” He said later that NASA is looking at “many various alternatives” for future years, with varying degrees of resources and corresponding cost and schedule risk.

While the overall OMB budget amendment hadn’t yet been delivered to Congress, Bridenstine said he spent the day on the phone with members to brief them on the NASA proposal. “I think there’s a lot of excitement on both sides of the aisle,” he said of their reactions. “When we talk about what NASA is trying to achieve, I will tell you there’s a lot of excitement.”

Bridenstine also used the call to announce that this 2024 lunar landing mission will be named Artemis, after the sister of Apollo and the Greek goddess of the moon. “I think it is very beautiful that, 50 years after Apollo, the Artemis program will carry the next man and the first woman to the moon.”