Fifty years ago this week, NASA astronaut Alan B. Shepard Jr. made space history when he took a few golf swings on the Moon during the Apollo 14 mission, successfully hitting two golf balls across the lunar surface. Space enthusiasts have debated for decades just how far that second ball traveled. It seems we now have an answer, thanks to the efforts of imaging specialist Andy Saunders, who digitally enhanced archival images from that mission and used them to estimate the final resting spots of the golf balls.

Saunders, who has been working with the United States Golf Association (USGA) to commemorate Shepard’s historical feat, announced his findings in a Twitter thread. Saunders concluded that the first golf ball Shepard hit traveled roughly 24 yards, while the second golf ball traveled 40 yards.

Shepard’s fondness for cheeky irreverence had popped up occasionally during his successful pre-NASA naval career, most notably when he was a test pilot at the Naval Air Station Patuxent River in Maryland. He was nearly court-martialed for looping the Chesapeake Bay Bridge during a test flight, but fortunately, his superiors intervened. When President Dwight D. Eisenhower established NASA in 1959, Shepard was selected as one of the seven Mercury astronauts. (The others were Scott Carpenter, Gordon Cooper, John Glenn, Gus Grissom, Wally Schirra, and Deke Slayton.)

Shepard beat out some fierce competition be chosen for the first American crewed mission into space. Russian cosmonaut Yuri Gagarin famously became the first man in space on April 25, 1961, thanks to repeated postponements of NASA’s Mercury mission, but Shepard wasn’t far behind. He made his own flight into space one month later, on May 5. Alas, he was a grounded after being diagnosed with Ménière’s disease, resulting in an unusually high volume of fluid in the inner ear.

Surgery four years later corrected the problem, and Shepard was cleared for flight. He narrowly missed being assigned to the famous Apollo 13 mission—NASA’s “most successful failure” and the subject of the 1995 Oscar-winning film, Apollo 13 (one of my all-time faves). Instead, Shepard commanded the Apollo 14 mission, which launched on January 31, 1971, and landed on the Moon on February 5.

To the Moon!

The idea for Shepard’s golfing stunt came out of a 1970 visit by comedian Bob Hope to NASA headquarters in Houston. An avid golfer, Hope cracked a joke about hitting a golf ball on the Moon, and Shepard thought it would be an excellent means of conveying to people watching back on Earth the difference in the strength of gravity. So he paid a pro named Jack Harden at the River Oaks Country Club in Houston to adapt a Wilson Staff 6-iron head so that it could be attached to a collapsible aluminum and Teflon sample collector. Once NASA’s Technical Services division added some finishing touches, Shepard practiced his golf swing at a course in Houston while wearing his 200-plus-pound spacesuit to prepare.

Most popular accounts describe Shepard as “smuggling” two balls and a golf club onto the spacecraft, but according to a later interview with Shepard, that wasn’t the case. The astronaut ran the idea past then-NASA director Bob Gilruth, who was initially opposed but relented once Shepard laid out the precise details. Shepard also assured Gilruth that the stunt would only be done once all the official exploration tasks had been completed and then only if the mission had gone off without a hitch.

On February 6, Shepard brought out the club and two balls. His spacesuit was too bulky to use both hands, so he swung the makeshift club with just his right hand. After two swings that were “more dirt than ball,” he made contact with the ball on his third swing, “shanking” it into a nearby crater. (“Looked like a slice to me, Al,” Apollo 13 pilot Fred Haise joked while watching from Mission Control.)

But Shepard nailed his fourth attempt. He sent the ball soaring out of camera range and declared that it traveled for “miles and miles and miles.” And as he had anticipated, the impressive 30-second time of flight perfectly showcased the difference in gravity between the Earth and the Moon. Not to be left out, crewmate Edgar Mitchell used a pole from a solar wind experiment as a javelin, which landed near the first golf ball. Once back on Earth, Shepard donated his makeshift club to the USGA museum and had a reproduction made that is now on display at the Smithsonian.

The location of the first ball Shepard hit has been known for quite some time—it’s sitting in a crater next to Mitchell’s javelin, about 24 yards from where Shepard stood when he took his swing. Saunders’ remastering of archival photos enabled him to locate the second ball that traveled farther, as well as one of the divots in the lunar soil.

“You can access Apollo imagery to very high quality online,” Apollo historian and video editor W. David Woods told Ars. “These shots were taken at 55 millimeters, the negatives and transparencies, for 55 millimeters a side. The scans they’ve done on them that are available online are 11,000 pixels across. So they’re enormous, huge pictures that you can really dive into, if you’ve got expertise in image processing.”

Image tricks

Saunders has that expertise. He relied on recent high-resolution scans of the original flight film, and he also used a technique known as substacking, among others.

“Some stuff was shot using 16 millimeter movie film,” said Woods. “Each individual image is quite small and grainy. But if you stack them one on top of the other, you cancel out the grain, you cancel out the noise, and you’re left with the imagery that’s inherent in all those frames. It’s a trick that astronomers use, where they take lots and lots of pictures of one area of the night sky. They cancel out the noise by stacking the images in just the same way.”

The Apollo 14 crew had taken a sequence of photographs from the window of the lunar module to capture the scene for posterity, which Saunders stitched together into a single panorama. According to Saunders, given the known location of the TV camera, it was possible to identify Shepard’s bootprints, showing his stance for his first two (failed) attempts. Using a known scale from images taken by the Lunar Reconnaissance Orbiter, he was then able to measure the point between the divot and the second golf ball to come up with his estimate for 40 yards.

Saunders, whose forthcoming book is entitled Apollo Remastered, estimates that a professional US Open golfer like Bryson DeChambeau could, in theory, hit a ball as far as 3.41 miles on the Moon, with a hang time of 1 minute 22 seconds—much farther (and longer) than Shepard’s feat. As he told the BBC:

Unfortunately, even the impressive second shot could hardly be described as “miles and miles and miles,” but of course this has only ever been regarded as a light-hearted exaggeration. The Moon is effectively one giant, unraked, rock-strewn bunker. The pressurized suits severely restricted movement, and due to their helmet’s visors they struggled to even see their feet. I would challenge any club golfer to go to their local course and try to hit a six-iron, one-handed, with a one-quarter swing out of an unraked bunker. Then imagine being fully suited, helmeted, and wearing thick gloves. Remember also that there was little gravity to pull the clubhead down toward the ball. The fact that Shepard even made contact and got the ball airborne is extremely impressive.

And of course, the astronaut’s legacy as the first human to play golf on the Moon remains secure.