Space is actually very close to us — just fly 62 miles upward and you’ll get there. But on the edge of the atmospheric frontier comes a zone of great risk: A lack of oxygen, high radiation and unpredictable weather conditions are all things that balloonists faced when they explored the highest altitudes.

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Space Men‘ is a new PBS documentary (premiering March 1, 9 p.m. EST) about this zone, which was explored in detail by human balloon flights during the 1950s and 1960s. History has sometimes forgotten about these men, even though they were exploring the high frontier years before the NASA Mercury astronauts donned a spacesuit. (For comparison, the first human flight into space was in 1962). And for anyone who watched Felix Baumgartner’s supersonic high-altitude balloon jump in 2012, ballooning is a type of research replete with as much drama as science.

“There is a sort of ‘Wild West’ quality that they were doing that definitely comes across, and it was this uncharted territory,” said Amanda Pollak, the writer, director and producer of the documentary, in an interview with Discovery News. She emphasized that science was the focus, but said: “I think at that moment in time, a lot of the rules had not been laid down because no one knew to lay them down yet.”

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Joseph Kittinger sits in the gondola before rising to the stratosphere during Project Manhigh. June 1957. Courtesy of Joseph Kittinger

Filmmaker Pollak was new to the space field when she embarked on a year of research into these balloonists, although she has done many other documentaries in American history on topics ranging from the Panama Canal to the year 1962. Her first introduction came from reading the book “The Pre-Astronauts: Manned Ballooning on the Edge of Space” by Craig Ryan. Luckily for Pollak, one of the major players was still alive: Joe Kittinger, who is perhaps best-known for making a famous high-altitude jump more than 50 years before Baumgartner.

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“Kittinger really brought the story to life,” Pollak said, “and having someone who was there and could not only tell his own story, but could talk about some of the other people and the impact of what they were doing, that impact in time, is irreplaceable. There is nothing that is going to write in a script that can capture that.”

Pollak’s documentary traces ballooning from its early days to the work of the Air Force’s John Stapp, who often volunteered to be his own test subject due to the risk of his work. He tried out oxygen systems in unpressurized aircraft at 40,000 feet. Later, he was known as the “fastest man on Earth” because he periodically would strap himself to a rocket-powered sled and see what extreme deceleration and acceleration did to his body. He survived broken ribs, temporary blindness and other injuries — but felt he should do the work because the science was needed.

The bulk of the documentary covers the three flights of Project Manhigh, which aimed to see how humans and ballooning systems would behave at high altitudes. Three flights took place in that program, including a then-altitude record of 101,516 feet set by David Simons in 1957. Simons is notable not only for the record, but for his research prior to that. He was the Air Force’s project officer for animal testing on V-2 rocket flights, and later a project officer for 60 unpiloted high-altitude balloon flights looking at the conditions high up in the stratosphere.

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The documentary also briefly mentions Project Excelsior, which saw Kittinger’s high-altitude jump from 102,800 feet in 1960. The record stood for 52 years until Baumgartner jumped successfully from 127,851 feet in 2012. Notably, Kittinger also participated in one of the Manhigh balloon flights prior to Excelsior and was also an adviser on Baumgartner’s team.

“The jump is dramatic and it’s very much linked [to Manhigh] because he’s actually now, in that moment, jumping into this incredibly hostile environment,” Pollak said. “Without the work on Manhigh, they never would have done that.”

The show airs March 1 at 9 p.m. Eastern, but check your local PBS affiliate for air time.