WASHINGTON -- A top NASA official urged the next administration to maintain current plans to return humans to the moon, warning that a change of destinations could result in a loss of U.S. leadership in space.

Speaking at a luncheon Oct. 30 during the American Astronautical Society's von Braun Space Exploration Symposium in Huntsville, Alabama, NASA Associate Administrator Jim Free said the agency needs to "stick with the plan" it has now through the Artemis lunar exploration campaign to return humans to the moon as a step towards later missions to Mars.

"We need that consistency in purpose. That has not happened since Apollo," he said. A change such as a shift in destinations, he said, "just takes all our programs back."

"We need to stick with the plan that we have. That doesn't mean we can't perform better," he said, such as improvements in contracts or technology. "But we need to keep this destination from a human spaceflight perspective."

"If we lose that, I believe we will fall apart and we will wander, and other people in this world will pass us by," he warned.

Free did not discuss any potential changes he thought could be made to NASA's human space exploration efforts. NASA did enjoy that "consistency in purpose" during the current administration, which largely maintained the Artemis effort and its goal of returning American to the surface of the moon that was announced by the earlier Trump administration.

Neither major presidential candidate has discussed space policy in much detail, but formal documents suggest support for continuity. The website of former President Donald Trump, the Republican nominee, refers to the party platform adopted in July that includes one paragraph on space: "Under Republican Leadership, the United States will create a robust Manufacturing Industry in Near Earth Orbit, send American Astronauts back to the Moon, and onward to Mars, and enhance partnerships with the rapidly expanding Commercial Space sector to revolutionize our ability to access, live in, and develop assets in Space."

The Democratic platform, finalized before President Joe Biden dropped out of the race in July, also includes only a brief statement about space: "Under his leadership, we'll continue supporting NASA and America's presence on the International Space Station, and working to send Americans back to the moon and to Mars." Vice President Kamala Harris, the Democratic nominee, has not elaborated on that statement, but her track record as chair of the National Space Council suggests she would continue most major programs and policies.

A wild card, though, is the suggestion made by Trump in recent campaign speeches that he may direct a highly accelerated program of human missions to Mars using vehicles developed by Elon Musk's SpaceX. "We will land an American astronaut on Mars. Thank you Elon," Trump said at an Oct. 24 rally. "Get that spaceship going, Elon."

Musk, weeks before the Trump campaign comments, has talked about launching humans to Mars using SpaceX's Starship vehicle as soon as the 2028 launch opportunity. "SpaceX plans to launch about five uncrewed Starships to Mars in two years," he wrote in one post on X, the social media network he also owns, Sept. 22. "If those all land safely, then crewed missions are possible in four years."

Industry officials, speaking privately, have expressed extreme skepticism about that timeline. They note that SpaceX is still in the early phases of development of Starship, and has yet to put a vehicle into orbit: all five integrated test flights to date have been suborbital. The company has many major technical milestones ahead of it, including demonstrating the ability to transfer propellants between Starship vehicles in orbit -- a requirement for any mission beyond Earth orbit, including Starship's use as a lunar lander -- and the high flight rate needed to carry out those fueling activities.

There would also be a competition for resources between the dozens of launches needed for sending a fleet of Starships to Mars with the launches needed for the Artemis 3 lunar landing mission, currently scheduled for late 2026, around the same time of the next Mars launch opportunity, which opens only once every 26 months. Even if the Artemis 3 landing slips, SpaceX is also required to carry out an uncrewed lunar landing before Artemis 3. The long duration of a flight to Mars as well as different entry, descent and landing conditions there would pose additional challenges.

Others note the challenges of keeping people alive on missions to Mars. "We all want to see space settlement happen, so now we have to roll up our sleeves and do the real work to make it happen," said James Logan, former chief of flight medicine at NASA's Johnson Space Center, during a session at the New Worlds Conference Nov. 2. "The tall pole in the tent is life science, and the engineers hate that."

Any spacecraft going to Mars, he argued, needed to be specially designed to maximize the shielding it offered astronauts from radiation. "It doesn't look like Starship," he said, instead proposing a spherical design with the crew at the center, surrounded by shielding.

At the Huntsville conference, Free spoke on stage in a fireside chat with Wayne Hale, a former NASA shuttle program manager, who said he "100%" supported Free's comments about not changing destinations. "I've seen programs get canceled and the disarray that brings," he said. "We can't stop and start. We've got to stay the course and continue to develop the vehicles and the programs."