A week after Vice President Mike Pence boldly declared that NASA would put humans on the Moon within five years, the space agency says it is still working on the details and the budget necessary to make this ambitious plan a reality. At the moment, NASA officials are crafting an amendment to the president’s recent budget request for fiscal year 2020 that would accommodate the expedited lunar return.

Before last week, NASA was targeting 2028 for the return of astronauts to the Moon, as part of President Trump’s directive to send people back to the lunar surface in a sustainable way. Pence drastically moved up that deadline to 2024 last Tuesday during a speech at the fifth meeting of the National Space Council, arguing that the original deadline was “just not good enough.” He also noted that five minutes before he took the stage, NASA administrator Jim Bridenstine told him that the agency had a plan to get back the Moon.

“we are moving rapidly to get you the details that you need.”

Now it seems that NASA is still working out the details of that plan and figuring out what it will cost. Speaking at a hearing of the House Science Committee, Bridenstine noted that NASA’s budget request for fiscal year 2020, released in March, did not account for the new goal and that’s why an amendment would be needed. In fact, the president’s budget request for 2020 cut funding to many of NASA’s programs, including the agency’s human exploration initiatives.

“It is absolutely true, Chairwoman, that the budget was focused on a 2028 Moon landing,” Bridenstine said at the hearing in response to a question from Rep. Eddie Bernice Johnson (D-TX), who chairs the Science Committee. “We have now gotten other direction from the president to go in 2024, and we are moving rapidly to get you the details that you need.” Johnson asked if the amendment would be ready by April 15th, and Bridenstine said that he thinks “we can get really close.”

The comments echo statements that Bridenstine made on Monday during a NASA town hall, which covered how the agency would pull off the vice president’s new directive. When asked if NASA will need extra funding to support the goal, Bridenstine ultimately said yes. “He said the mission matters more than the means,” Bridenstine said at the town hall, referring to Pence. “To me that says, ‘we’re going to need additional means.’ I don’t think anybody can take this level of commitment seriously, unless there are additional means. And so that’s what I intend to support as we go forward.”

But to receive that extra money, NASA needs support from Congress, which is responsible for appropriating funding to the agency every year. Bridenstine said he hopes to get that support with the new amendment.

“we’re going to need additional means.”

The money influx is ultimately meant to accelerate NASA’s current strategy to put humans on the lunar surface again. NASA plans to build a space station in orbit around the Moon called the Gateway, which will serve as an outpost for future lunar astronauts. From the Gateway, crews will travel to and from the surface in landers and modules developed by private companies. And to get humans to this space station, NASA has been working on the biggest vehicle of all: a massive new rocket called the Space Launch System, or the SLS. When complete, the rocket is meant to launch a new crew capsule called Orion on trips to deep space, carrying humans to the new Gateway.

Developing this hardware has proven time consuming and costly, though. NASA has been working on the SLS for the better part of the last decade, and the rocket’s debut has been consistently delayed. The SLS was meant to fly for the first time in 2017, but this inaugural mission has been postponed to June 2020 — a date that is also looking increasingly unlikely. At today’s hearing, Bridenstine mentioned that NASA is working on getting it ready by the end of 2020.

These delays prompted NASA to look into alternatives for launching Orion by next year, possibly by using a commercial rocket. During today’s hearing and yesterday’s town hall, Bridenstine said that NASA considered multiple options that entailed using the Delta IV Heavy, a rocket made by the United Launch Alliance, and SpaceX’s Falcon Heavy. Most scenarios required two rocket launches to get Orion around the Moon, since neither of these commercial vehicles are as powerful as the future SLS. Bridenstine did say that a single launch of the Falcon Heavy could be used to get Orion to the Moon, but so many changes would need to be made to the rocket that it is unlikely to happen by next year (however such an option could be used in the future).

“That was a decision by the president of the United States.”

So for now, the current plan is to stay committed to the SLS and get it ready for its first flight with Orion. “The SLS is the best — in fact, it’s the only option,” said Bridenstine, referring to the mission with the crew capsule next year. And the administrator said the amendment will mostly focus on speeding up all of the current components of the lunar return that NASA has been working on, including the SLS, Orion, the Gateway, and lunar landers.

That means NASA’s plans are staying relatively the same, even in the face of this new call to action. Bridenstine also admitted that NASA was not the driving force behind this decision, though the agency was consulted beforehand. “That was a decision by the president of the United States, announced by the vice president of the United States,” he said.