Why Humanity Keeps Putting Off the Trip to Mars

September 28, 2015 1:20 PM EDT

The new movie The Martian, the story of an ill-fated NASA mission to Mars, takes place in the relatively near future. While some of the science has been nit-picked—though relatively little, considering it’s a movie—one aspect is, historically speaking, completely believable: the idea that human beings would be sending manned missions to the Red Planet is the very near future.

As NASA revealed that scientists have found evidence of water on Mars on Monday, our solar system neighbor became the focus of renewed interest—but it’s been decades since humankind first heard that a Mars mission was imminent.

It started in the mid-1960s, even before the moon landing, as the fifth-ever class of astronauts chosen by NASA were told that a Mars mission could possibly be in their future. By 1969, with the lunar landing a success, they had a timeline: engineer Wernher von Braun said the American space program could get there by 1982, while the more cautious Vice President Spiro Agnew was aiming for the year 2000 at the latest.

MORE: A Brief History of the Search for Water on Mars

A panel headed by Agnew was, later that year, settled on a middle ground: “If Congress compromises on a maximum NASA budget of $7.65 billion by 1980,” TIME reported, “the Martian touchdown can be achieved in 1986.” Over the next few years, the 1986 deadline continued to be discussed. (Attention, Hollywood: By 1972, NASA even got into the weeds with the question of what to do about the astronauts’ inevitable romantic entanglements during a 590-day mission.)

Fast-forward to the mid-1980s. Humankind was not on Mars.

But that didn’t mean we weren’t still trying. By 1985, the idea of a joint U.S.-Soviet mission was floated by space experts from around the world. It was to be a Cold War-defying act of scientific greatness, made possible by splitting the bill. The deadline that time around: 2010.

Hopes of that idea becoming reality were temporarily dashed the following year by the Challenger space shuttle disaster, which led NASA to recalibrate its entire mission, but by 1988 it was back on track. “A manned trip to Mars, long the stuff of science fiction, now appears to be just a matter of time. The mystic planet, glowing red and ever brighter in the night skies, is heading toward its closest approach to the earth in 17 years this September, tantalizingly near and beckoning,” TIME noted in a cover story about the progress the U.S. and the USSR were both making in research and preparation for such a trip.

MORE: What the Modern Presence of Water on Mars Means

By the start of the ’90s, President George H. W. Bush had adjusted the target to aim for “astronauts on the red sands of Mars by 2019,” per TIME. Science experts like TIME’s Michael Lemonick agreed that 2020 was a “reasonable” estimate for when we’d get there. But, as the next decade progressed, there was more and more news of probes and rovers going to Mars, and less and less news of potential manned missions. At the dawn of a new century that trend continued.

The Jan. 26, 2004, cover of TIMECover Credit: ED GABEL

Then, however, George W. Bush announced that Mars was once again a priority for NASA. The summer before the 2004 election, he laid out a plan for returning to the moon around 2015 and getting to Mars not too long after. “[Though] the year 2030 was bandied about in the press as a target for putting a man on Mars, the President was careful not to set a date,” TIME’s Jeffrey Kluger noted. Some experts at the time even saw 2030 as unnecessarily far away; with real dedication to the mission, they estimated, the 2010 date could have been met.

And now 2010 has come and gone, and 2030 is practically just around the corner. But we haven’t given up: just about a month ago, none other than Buzz Aldrin declared that he wanted to see humans on Mars by 2039.

So The Martian may yet become even more scientifically accurate than its creators could have planned, something that future astronauts may well find worth raising a glass (of Martian water) to celebrate.

Read TIME’s Jeffrey Kluger on The Martian: The Martian Celebrates the Gutsy Ambition That We’ve Denied the Real NASA

Read a 1972 imagining of a mission to Mars, here in the TIME Vault: 1986: A Space Odyssey to Mars

PHOTOS: The Most Beautiful Panoramas and Mosaics From Opportunity’s Decade on Mars

Rover tracks disappear toward the horizon like the wake of a ship across the desolate sea of sand between the craters Endurance and Victoria on the Meridiani Plains. NASA— JPL-Caltech / Cornell University

The Mars Rover Spirit took this sublime view of a sunset over the rim of Gusev Crater, about 80 kilometers (50 miles) away. NASA—JPL-Caltech / Texas A&M / Cornell

A false-color image of Endurance Crater. In this image, tendrils of sand less than 3.3 ft (1 m) high extend from the main dune field toward the rover. Dunes are a common feature across the surface of Mars. Before the rover headed down to the dunes, mission managers first established whether the slippery slope that led to them was firm enough to ensure a successful drive back out of the crater. Otherwise, the dune field would become a sand trap. NASA—JPL-Caltech / Cornell University

Tiny spherules pepper a sandy surface in this 3-centimeter (1.2-inch) square view of the Martian surface. — Tiny spherules, photographed by Opportunity, pepper a sandy surface in this 1.2-in (3 cm) square view of the Martian soil. Nicknamed "blueberries" by mission scientists, the little pellets are actually hematites, an iron oxide typically formed in standing water—of which Mars once had plenty.NASA—JPL-Caltech / Cornell / USGS / Cathy Weitz

Spirit obtained this view of the area called Home Plate while parked atop Husband Hill. — Spirit obtained this view of the area called Home Plate while parked atop a formation called Husband Hill. The colors emphasize differences in rock weathering. A large dust devil appears as the V-shaped discoloration in the sky at the top right.NASA—JPL-Caltech / Cornell University

NASA's Mars Exploration Rover Opportunity used its panoramic camera to record the East Rim of Endeavor Crater, on October 31, 2010. — The Opportunity rover used its panoramic camera to record the East Rim of Endeavor Crater, on October 31, 2010. The view is presented in false color to make differences in surface materials more visible. A portion of Endeavour Crater's eastern rim, nearly 19 miles (30 km) distant, is visible.NASA—JPL-Caltech / Cornell

NASA's Mars Exploration Rover Spirit acquired this false-color image after using the rock abrasion tool to brush the surfaces of rock targets informally named "Stars" (left) and "Crawfords" (right). — NASA's Spirit rover acquired this false-color image after using its abrasion tool to brush the surfaces of rock targets informally named "Stars" (left) and "Crawfords" (right). Small streaks of dust extend for several centimeters behind the chips and pebbles in the dusty soil. NASA—JPL-Caltech / USGS / Cornell University

PHOTOS: The Most Beautiful Panoramas and Mosaics From Opportunity’s Decade on Mars

More Must-Reads From TIME