Jim Toomey has a weakness for space memorabilia, but he doesn’t have unlimited funds. So he had to keep his desires in check as he perused an online auction of NASA relics in May 2012. The Bradenton, Florida, entrepreneur mustered the self-discipline to skip the $53,758 baggie from Apollo 15 that had once held lunar dust, as was well the Gemini 5 log book that went for $33,844. He instead scooped up what he terms “a whole bunch of space junk.” His haul included a dented bracket from a Space Shuttle’s tail fin ($240), a spacesuit’s heater cable ($240), and four reels of 16-mm film that were advertised as having something to do with Viking, the 1970s NASA program that landed America’s first two spacecraft on Mars ($360).

Toomey promptly donated all his NASA curios to the South Florida Museum, where he served as a trustee. Though the museum appreciated the gifts, it deemed them too offbeat for public display. Instead they wound up in a box on a backroom storage shelf, amid a sea of other forgotten artifacts.

Toomey didn’t give the space junk another thought until September 2015, when he received an odd phone call from the Boston auction house that had sold him the goods. The caller said the company had been contacted by an engineer from NASA’s Jet Propulsion Laboratory named Rob Manning who was desperate to locate the Viking films. According to Manning, NASA had discarded the reels by accident; they’d been left in a file cabinet marked for sale as government surplus during an office move in 1999.

Toomey agreed to speak to Manning and assured him that the objects had been preserved rather than melted down for their silver. During that conversation, a grateful Manning revealed why he and his JPL colleagues were so eager to view the films: They contained the only surviving footage of the August 1972 qualification test for Viking’s parachute, the contraption responsible for safely decelerating the program’s landers through the Martian atmosphere. Because that atmosphere is 99 percent thinner than Earth’s, Viking’s engineers knew their spacecraft would be plummeting at supersonic speeds as they neared the planet’s surface. The engineers had thus built a novel parachute that could endure such punishing conditions—a 2,200-square-foot expanse of white polyester with braided nylon suspension lines.

A parachute successfully landed a capsule at White Sands in 1972. NASA

The August 1972 test had confirmed their success. A balloon first carried a 1,900-pound capsule to the edge of the stratosphere at New Mexico’s White Sands Missile Range. When the vehicle dropped free from the balloon, it fired rockets that cranked up its speed to nearly 1,600 miles per hour. At that point, a small explosive blasted open the compartment that held the parachute. An on-board camera captured the violence of that moment, as the polyester jerked and shuddered before mellowing into a stable hemisphere. The films that Toomey had bought at auction, and which NASA wished to reclaim, were the sole visual evidence of that engineering triumph.

NASA’s supersonic parachutes have barely evolved in the 46 years since that milestone above the New Mexico desert. The Viking model worked so well that the space agency kept using it for all of its Mars missions, thereby eliminating the need to spend hundreds of million of dollars on new tests. When the Curiosity rover alighted inside the Gale Crater in 2012, for example, it did so with the aid of a parachute that was essentially a larger version of the one that had decelerated the Viking 1 lander 36 years earlier.

But the trusty Viking parachute is finally on the verge of obsolescence. The aging design can’t provide the drag necessary to slow down payloads much heavier than a ton—a significant problem for NASA given that its longterm Martian dreams involve vehicles that will weigh more than 20 Curiosities combined. And so the engineers at JPL have been scrambling to come up with a much tougher replacement, a parachute that can help solve the Martian version of the last-mile problem for decades to come.