Fifty years ago, the world watched in amazement as Neil Armstrong planted his boots firmly on the lunar surface. We haven’t returned to the moon since 1972, but that may soon change.

An estimated 600 million people watched the first grainy images of a human exploring another world, captivating the public and making front pages of newspapers for weeks.

Despite another five decades of incredible achievements that include successful Mars missions, deep-space probes and nearly 19 years of continuous occupation of the International Space Station, only 12 men have walked on the moon -- the most recent in 1972. The Apollo 11 landing on July 20, 1969, remains the high-water mark for the public’s interest in space flight.

President Donald Trump has promised that Americans will again visit the moon and beyond, and NASA is scrambling to meet aggressive deadlines in its Artemis mission to put humans back on the moon within five years. But unlike the audacious vision in the 1960s that made the seemingly impossible come true, fueled by the Cold War and devotion to President John F. Kennedy’s legacy, today’s political climate and the astronomical costs of space programs could make things more difficult.

“Space was fairly new,” said retired Lt. Gen. Tom Stafford, commander of the Apollo 10 mission. “Every mission I flew was something that had never been done before. The whole public was really excited about going.”

Stafford and his crew flew to the moon but didn’t land. It was a dry run for the next mission carrying Neil Armstrong and Buzz Aldrin and Michael Collins.

The next few moon missions kept eyes on the program, including the ill-fated Apollo 13.

“But after that, you keep going back, repeat, repeat, repeat,” Stafford said. “After Skylab and the shuttle program stuck to low-earth orbit, interest in space travel slowly died off.”

A shift in attitudes

Since the final Apollo mission in 1972, there have been attempts to launch another manned moon program. None has earned the public and political support needed to leave the ground.

Americans generally support the space program -- 1 in 5 describe themselves as "very interested" in exploration, and only a third believe its benefits are greater than the costs.

But just 18 percent of Americans support a manned Mars mission, and 8 percent want humans to return to the moon, said Clifford Young of the Ipsos market research company.

“American public opinion says we’ve done that, we’ve been there,” Young told C-SPAN, adding that near-Earth space exploration remains a priority for the public because of environmental and security interests. “They are not interested in going to the moon, to Mars as much as using space to help our existence on Earth, better our lives on Earth.”

The shift in attitudes hasn’t been lost on NASA as it plans the Artemis mission that could eventually bring the next man and first woman to the lunar surface. Plans include a permanent infrastructure that could be a staging point for future Mars missions.

Reigniting imaginations

NASA Administrator Jim Bridenstine said the early years of the space program were framed as a competition between the United States and Soviet Union.

“These kinds of things were at the at the very top of people's minds back in the 1960s and early 1970s, and I think it became somewhat normalized as we went into the space shuttle program,” Bridenstine said in an interview with The Oklahoman. “But I would also say that under this administration, they want to go back to the moon, this time sustainably.”

The search for life in other worlds could reignite the public’s imagination, Bridenstine said, but there’s more to the equation.

“If we can discover life on a world that's not Earth, I think it'll change the game. I think people will be enthused (for) what else is out there that we don't know about,” he said. “So yes, human spaceflight enthuses and inspires the next generation just like it inspired the generation of the 1960s. But I would also say that finding life on another world is equally as important to that enthusiasm."

NASA was originally tasked to launch the Artemis mission by 2028, but Trump moved the finish line ahead four years. The decision to accelerate was part of a political calculation, Bridenstine said.

“NASA has amazing capabilities to retire technical risk, and we do it all the time,” he said. “Where we have not been good historically is the political risk.”

Previous attempts to organize deep-space missions failed because they ran into delays and cost overruns. Trump’s plan hasn’t earned total confidence from the scientific community nor Congress, although funding measures to send more than $5 billion for deep-space exploration systems were recently introduced in the House and Senate.

Setting goals

The Artemis mission includes plans for the Gateway, a logistics station that would orbit the moon and allow spacecraft to dock. Officials hope it will be used as a launch point for future moon missions and eventual manned trips to Mars.

It would have a reusable lunar lander to reduce costs and be used for refueling once moon mining operations are able to convert water on the surface into liquid hydrogen-based fuel.

House Democrats have complained that NASA hasn’t shown full plans or detailed budgets for the multi-year project; in this year’s funding bill, the House Appropriations Committee noted how clear mission goals and deadlines can galvanize an agency and a nation behind Artemis, saying it believes that “without firm goals and specific years by which to achieve those goals, programs could drift and languish.”

“We still have a lot of unanswered questions,” said Kendra Horn, chair of the House Subcommittee on Space and Aeronautics. “In order to set NASA up for success, to ensure that we are authorizing and appropriating enough money, we got to have an idea of what it takes to get there.”

Having certainty about what NASA will need in future years also gives confidence to private contractors bidding on space projects, she said. The Artemis mission relies heavily on commercial partnerships.

U.S. Rep. Frank Lucas of Oklahoma, ranking member of the House Science, Space and Technology Committee, said he’s asking the agency to put realistic numbers in its budget proposals.

During the early Mercury, Gemini and Apollo missions, he said, officials made plenty of adjustments.

“There was a lot of flying by the seat of your britches. My concern is, can we put enough resources in there to get the job done?” said Lucas, a Republican. “I think what NASA's laid down is a practical, reasonable blueprint to move forward. I personally think it will cost more, but I want to get it done in the safest possible way.”