U.S. District Judge Timothy Kelly, left, swears in Jared Isaacman, right, as the 15th administrator of NASA, as Isaacman`s parents, Donald and Sandra Marie, join him Thursday in Washington, D.C.Bill Ingalls / NASA via Getty Images

NASA`s new leader, billionaire entrepreneur Jared Isaacman, is making his priorities for the space agency clear in his first days on the job.

Isaacman was sworn in Thursday as the 15th administrator of NASA. The same day, President Donald Trump signed an executive order directing NASA to return astronauts to the moon by 2028, begin the development of a permanent outpost on the lunar surface by 2030, and lay the foundations for future exploration of Mars.

The order will likely provide a roadmap for Isaacman and NASA.

"Within the next three years, we are going to land American astronauts again on the moon, but this time with the infrastructure to stay," Isaacman told NBC News in an interview after his swearing in on Thursday.

He has stepped into the role at a key time for NASA: The Trump administration has made it an urgent objective to return astronauts to the moon before China`s astronauts reach the lunar surface.

"We are faced with another space race," Isaacman said.

The next phase of NASA`s return-to-the-moon program, known as Artemis, could launch as early as February. The mission, Artemis II, will send four astronauts on a roughly 10-day flight around the moon to test the agency`s Space Launch System rocket and Orion spacecraft.

The Artemis III flight that will follow is expected to land astronauts near the moon`s south pole.

Under Isaacman, NASA is expected to continue its push toward more commercialization. Companies like SpaceX and Blue Origin are set to play a critical role in the space agency`s efforts to return to the moon, and Isaacman said other private space firms will support the agency`s lunar ambitions, as well.

Trump`s executive order on space policy calls for developing a "vibrant commercial space economy through the power of American free enterprise," and outlines a plan to wind down the International Space Station by 2030 and launch commercial space stations in its place.

The order also focuses on nuclear power in space. Building on a directive from Transportation Secretary Sean Duffy, who served as acting administrator of NASA before Isaacman was confirmed, it sets a goal to develop a nuclear reactor that is ready to launch to the moon by 2030.

Isaacman said nuclear power in space will be key to exploration beyond the moon, including future missions to Mars.

One of the challenges he faces as administrator, however, will be executing the White House`s vision with a limited budget.

Current funding across the U.S. government extends through Jan. 30. After that, NASA faces the possibility of significant budget cuts, particularly to its science operations.

Despite that looming obstacle, Isaacman expressed optimism about the agency`s ability to juggle the administration`s priorities.

"Whether it`s $25 billion or $20 billion, that`s an awful lot of money coming into the agency every single year," he said. "We`ve got the best and brightest that are capable of taking on numerous challenging endeavors - the near impossible - simultaneously."

"In the president`s space policy, it`s the opportunity to go back to the moon, establish the infrastructure there, and then make investments in the future technology like nuclear to set up for Mars missions," Isaacman said. "I think with the resources that are provided, the commitment from the president here in the White House with that space policy, we`re going to be able to get the job done."