President Donald Trump welcomed Apollo 11 astronauts at the White House on Friday to celebrate the 50th anniversary of Americans landing on the moon and planting the American flag there.

“Tomorrow will represent 50 years from the time we planted a beautiful American flag on the moon,” Trump said. The anniversary is on Saturday.

Trump called the moon landing event “one of the greatest achievements ever” and said that the United States was committed to continuing the exploration of space.

Buzz Aldrin, the Apollo 11 lunar module pilot, and Michael Collins, the Apollo 11 command module pilot, came to the White House for the event as well as Neil Armstrong’s two sons. Other family members of the three astronauts also attended the event. (Armstrong, the first man to land on the moon, died in 2012.)

“These are incredible men,” Trump said.

One of Armstrong’s sons explained that the benefit of space exploration was the inspiration it provided to people to pursue science and technology.

“The value of that is tremendous, and I think we need more of that,” he said.

Trump said he was pleased that the United States no longer had to rely on Russia to get up into space, thanks to the private space industry working with NASA.

“NASA is back,” Trump said. “We’re having rich guys use it and pay us rent; I like that.”

NASA Administrator Jim Bridenstine also attended the event, declaring that it was important for the United States to return to the moon long-term in order to launch a mission to Mars.

“We prove that out on the moon, then we go to Mars,” Bridenstine said.

But Collins appeared to disagree.

“Mars direct,” he said shortly.

Aldrin disagreed. “You’re impatient,” he interjected off camera.

Trump brought up the debate live in the Oval Office during the Oval Office meeting with the press.

Aldrin supports building a moon base and space station to help launch future trips to Mars, a proposal that Vice President Mike Pence and Bridenstine also favor.

“Who knows better than these people right?” Trump asked, pointing at the two astronauts.

But Bridenstine repeated that NASA needed to learn how to live onsite on the moon using available resources for long-term exploration. He argued that the mission to Mars should be launched from a space station to escape the earth’s gravity.

Former President Barack Obama did not support the idea of returning to the moon first, voicing his opinion on the matter in 2010.
“Now, I understand that some believe that we should attempt a return to the surface of the Moon first, as previously planned,” he said. “But I just have to say pretty bluntly here: We’ve been there before.”

Trump seems fascinated by the idea of going straight to Mars and only favors talk about returning to the Moon as long as it is focused on the ultimate mission to Mars.