Sixty years ago, spurred by competition with the Soviet Union, the United States created NASA, launching a journey that would take Americans to the moon within a decade.
Since then, the US space agency has seen glorious achievements and crushing failures in its drive to push the frontiers of space exploration, including a fatal launch pad fire in 1967 that killed three and two deadly shuttle explosions in 1986 and 2003 that took 14 lives.
Now, NASA is struggling to redefine itself in an increasingly crowded field of international space agencies and commercial interests, with its sights set on returning to deep space.
These bold goals make for soaring rhetoric, but experts worry the cash just isn't there to meet the timelines of reaching the moon in the next decade and Mars by the 2030s.
And NASA's inability to send astronauts to space—a capacity lost in 2011 when the space shuttle program ended, as planned, after 30 years—is a lasting blemish on the agency's stellar image.
While US private industries toil on new crew spaceships, NASA still must pay Russia $80 million per seat for US astronauts to ride to space on a Soyuz capsule.
How it started
In 1957, the Soviet Union launched the first satellite into space with Sputnik 1, while US attempts were failing miserably.
The US government was already working on reaching space, but mainly under the guise of the military.
President Dwight D. Eisenhower appealed to Congress to create a separate, civilian space agency to better focus on space exploration.
He signed the National Aeronautics and Space Administration Authorization Act into law on July 29, 1958.
NASA opened its doors in October 1958, with about 8,000 employees and a budget of $100 million.
The Soviets won another key part of the space race in April 1961 when Yuri Gagarin became the first person to orbit the Earth.
A month later, John F. Kennedy unveiled plans to land a man on the moon by decade's end.
"No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space; and none will be so difficult or expensive to accomplish," the US president said.
The Apollo program was born.
In 1962, astronaut John Glenn became the first American to orbit the Earth. In 1969, NASA astronaut Neil Armstrong became the first man to walk on the moon.
American astronauts of the era were national heroes—military pilots with the combination of brains, guts and grit that became known famously as "The Right Stuff," the title of the classic Tom Wolfe book.
Armstrong's words as he set foot on the lunar surface—"one small step for man, one giant leap for mankind"—were heard by millions around the world.
"Apollo was a unilateral demonstration of national power," recalled John Logsdon, professor emeritus at George Washington University's Space Policy Institute.
"It was Kennedy deciding to use the space program as an instrument of overt geopolitical competition that turned NASA into an instrument of national policy, with a very significant budget share," he told AFP.
A total of five percent of the national budget went to NASA in the Apollo era.
Now, NASA gets about $18 billion a year, less than a half percent of the federal budget, "and it is no longer the same instrument of national policy," Logsdon said.
More glory days followed in the 1980s with the birth of NASA's shuttle program, a bus-sized re-usable spacecraft that ferried astronauts into space, and eventually to the International Space Station, which began operation in 1998.
But what is NASA today?
President Donald Trump has championed a return to the moon, calling for a lunar gateway that would allow a continuous stream of spacecraft and people to visit the moon, and serve as a leaping off point for Mars.
Trump has also called for the creation of a "Space Force," a sixth branch of the military that would be focused on defending US interests.
NASA has long been viewed as a global leader in space innovation, but today the international field is vastly more populated than 60 years ago.
"Now you have something like 70 countries that are one way or another involved in space activity," said Logsdon.
Rather than competing against international space agencies, "the emphasis has shifted to cooperation" to cut costs and speed innovation, said Teasel Muir-Harmony, curator at the National Air and Space Museum.
'How can NASA take advantage of this?'
NASA administrator Jim Bridenstine told a recent panel discussion he is keen to work with other countries that are striving toward space.
He mentioned the possibility of boosting cooperation with China, and how he recently traveled to Israel to meet with commercial interests that are at work on a moon lander.
Bridenstine said the reason for his visit was to find out "how are you doing this, what are you doing and is there a way NASA can take advantage of it?"
NASA is backing away from low Earth orbit, looking to hand the space station over to commercial interests after 2024, and spending millions in seed money to help private companies like SpaceX and Boeing build capsules to carry humans to space in the coming years.
In this environment, Bridenstine said figuring out what NASA does, versus what it buys as a service from commercial providers, will be "one of the fundamental challenges I think I am going to face over my tenure."
Bridenstine said Trump's budget requests for NASA have been "very generous."
With its eyes on a crew mission to the moon in just five years' time, NASA plans to devote about $10 billion of its nearly $20 billion budget for 2019 to lunar exploration.
Bridenstine's predecessor at NASA's helm, retired astronaut Charles Bolden, sounded a note of caution against repeating the mistakes of the shuttle era, when the United States ended its human exploration program without another spacecraft ready to take its place.
"We cannot tolerate another gap like that," Bolden said.
"It is really critical for NASA to facilitate the success of commercial entities to take over" in low Earth orbit, some 250 miles (400 kilometers) above the planet.
"And then for NASA to do what it does so well. Be the leader in lunar orbit."
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