NASA Administrator Jim Bridenstine said Monday that the agency will need additional funding to meet a White House mandate to land people on the moon by 2024. But he did not say how much more money NASA would need or provide any specific details of how it plans to accomplish the mission.

Speaking at a town hall meeting at NASA headquarters, Bridenstine made it clear NASA was scrambling to figure out how to get to the lunar surface before the presidential election in 2024. He said he was fully aware that past administrations have set bold goals to explore the moon or Mars, only to pull them back as Congress fails to provide funding or a new administration comes in and cancels previous plans.

During the presidency of George W. Bush, NASA was directed to go to the moon. Under Barack Obama, reaching an asteroid and Mars were the missions. Now, under President Donald Trump, it's the moon again. Many in the space community compare that record to the scene in the cartoon strip "Peanuts" when Lucy pulls the football away just as Charlie Brown is about to kick it.

"I hear the comment all the time about Lucy and the football," he said. "This is not Lucy and the football. In the executive branch, people are very serious, we are going to the moon and going fast."

Bridenstine's comments came several days after Vice President Mike Pence called for NASA to return to the moon within five years, an ambitious goal that took many at NASA by surprise. In a speech before the National Space Council last week, Pence said that the agency needed to have a much greater sense of urgency. He took aim at Boeing and other NASA contractors building the Space Launch System (SLS) rocket, which is supposed to be used in the moon missions but is years behind schedule and billions of dollars over budget.

Pence also fired a salvo at NASA itself, saying if it can't get astronauts to the lunar surface in five years "we need to change the agency, not the mission."

The questions NASA employees posted on the agency's website ahead of the town hall gave voice to the skepticism that has reigned since Pence voiced his new goal. Under the previous plan, NASA was looking at sending people to the moon by 2028. Moving it up by four years came as a shock.

"Please explain in detail what 'We'll change the Agency, not the mission' entails," one employee wrote.

"Accelerating our return to the moon is an unfunded mandate," asked another. "How will we do it without gutting our other important missions?"

Bridenstine offered few specifics during his Monday presentation. He said the agency planned to use what's known as a Gateway, a sort of space station that would be placed in orbit around the moon. But the agency has yet to award a contract to build it. It also does not have the landing craft needed to carry astronauts from the Gateway to the lunar surface and back again.

NASA is also struggling with its moon rocket, the SLS. Frustrated with the constant delays, Bridenstine told a Senate hearing last month that he would look at using other, commercial rockets for the upcoming test flight of the Orion spacecraft that would ultimately be used to fly astronauts to the lunar Gateway.

But the possibility of sidelining NASA's main rocket, the construction of which provides thousands of jobs in many congressional districts, led to a withering backlash from Congress, and Bridenstine has since backtracked, saying it just was not technically feasible to use commercial rockets for the mission.

Bridenstine told the town hall Monday that he was confident that the White House would push for additional funding since returning to the moon was a mandate "from the top."

"We're going to need additional means," Bridenstine said. "I don't think anyone can take this level of commitment seriously unless there are additional means."

But the White House's budget request of $21 billion for NASA for next year is $480 million less than what Congress appropriated in this year's spending plan.

Still, Bridenstine said he was confident the agency would achieve the White House's goal, whatever the difficulties.

“I’m not suggesting there are not holes here,” he said. “The reality is we’re moving quickly, and we’re looking at all options. There is nothing off the table.”