The Off-Roading Astronauts of Apollo

Apollo 17’s Gene Cernan test-drives the third rover used on the moon, minutes after the machine was deployed on December 11, 1972.

(Photo: Courtesy NASA, scan by Kipp Teag)

The Off-Roading Astronauts of Apollo

Published: Jun 23, 2021

The later moon missions didn’t grab as much attention as the first landing in 1969, but they had something very cool on the gear front: the lunar rover, a lightweight go-kart that gave crews unmatched mobility on another world

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Alas, Neil Armstrong.

After traveling nearly a quarter-million miles to reach the moon’s Sea of Tranquility in July 1969, the Apollo 11 astronaut didn’t get much time to��look around. His space suit was pumped up��like an all-season radial. Grasping tools exhausted his hands in minutes. From inside his helmet, he couldn’t see his own feet. And the effort required to lope stiff-legged across the powdery surface guzzled the air and cooling water in his backpack, limiting his time outside the relative safety of the lunar module.

So it was that in man’s first visit to another celestial body, Armstrong and his crewmate, Buzz Aldrin, covered very little ground; the farthest either ventured from the lander was when Armstrong embarked on an unscripted jog for last-minute pictures and rock samples—about 65 yards. All their travels would fit inside a football field, with plenty of room to spare.

The Apollo 11 crew earned an enduring place in the annals of exploration, and rightly so, not because of what they did on the moon, but because they were there, and there first. The courage it required, the precision it demanded, and the sheer boldness of the undertaking thrilled the world. The names of Erikson, Peary, and Henson have likewise stayed with us. Amundsen and Cook. Magellan. Marco��Polo.

But the fact is, the greatest achievements of America’s lunar adventure came later, when people were��no longer hanging on every word the moonwalkers spoke or following every step they took, on��missions that were given comparatively little notice at the time and are recalled dimly today.

It wasn’t until the fourth moon landing, two years after Apollo 11, that NASA supplied an Apollo crew with the tools it needed to take real advantage of its presence amid the “magnificent desolation” of that forbidding, airless environment:��A beefed-up lunar module capable of supporting three full days on the regolith. Redesigned backpacks that supplied air,��water, and power for longer explorations. And the most transformative equipment of all,��a spindly aluminum go-kart that folded like a business letter to fit inside the lander��and weighed all of 78 pounds in the moon’s one-sixth gravity.

Its tires were made of wire mesh. Its seats looked like beach chairs. Its four electric motors��together managed just one horsepower. Its floorboard was one-fiftieth of an inch thick, about the same as the slimmest wood veneers, and would snap under an astronaut’s weight on Earth. Yet the lunar rover—or, in NASA parlance, the lunar roving vehicle, or LRV—upended all expectations of what was possible in a brief visit to another world.

“They were looking at how could the astronauts get the most bang for the buck—in getting around, in picking things up, in exploring,” says Saverio “Sonny” Morea, who oversaw the project at NASA’s Marshall Space Flight Center in Huntsville, Alabama. “A car came up pretty fast.”

A couple of seconds passed before he added: “Though it’s not a car. It’s really a spacecraft.”

Astronaut Alan B. Shepard Jr. works during Apollo 14’s lunar visit in February 1971. Beside him is the Modular Equipment Transporter, a handcart for tools and rock samples. (Courtesy NASA, assembly by David Harland)

Consider the two lunar missions of 1971—Apollo 14, the third to land, which set down in the Moon’s rugged Fra Mauro region in early February, and Apollo 15, which 50 years ago this summer��sent��its astronauts to a plain rimmed by sky-high mountains and a mammoth canyon, and carried the first LRV.

On their second excursion from their lunar module,��Antares, Apollo 14 astronauts Alan B. Shepard Jr. and Edgar Mitchell embarked on the longest walk of the Apollo campaign, a hike over undulating ground to the rim of Cone Crater, a half-mile away, where geologists hoped to find rocks from deep in the moon that had been blown out of the hole during its creation. Equipped with a rickshaw-style handcart for their tools and collected samples, they set out confident that they knew just where the crater was—“right over that way,” as Mitchell put it. Their maps depicted the landmarks they’d see en route.

But the moon played tricks on them. The horizon was weirdly close. The sky was utterly black. The monochromatic surface concealed its features behind swells and declivities. And the astronauts’ perception of size and distance was jumbled by the absence of any visual yardsticks—trees or houses or clouds—so that a large rock some distance away looked no different from a smaller one close by. The same was true of craters: within minutes, the pair mistook small depressions for large ones, identified them by the wrong names, and in so doing misjudged their location, and thus their speed. When they first stopped to gather samples, they were hundreds of yards short of where they thought they were.

Not long after, they realized that the surrounding moonscape didn’t match their maps, and disagreed on what they did see. Shepard pointed out what he took to be Weird Crater, a cluster of overlapping depressions off to their south. Mitchell thought they had to be “considerably past Weird.” Mission control��in Houston, with only the astronauts’ verbal descriptions to go on, had no way of knowing who was right, assuming either was.

The dust underfoot, soft and yielding, began to tilt. “We’re starting uphill now,” Mitchell told Houston. “Climb’s fairly gentle at this point, but it’s definitely uphill.” Moving in a pressurized space suit was taxing enough on flat ground; soon both astronauts were breathing hard. An hour into the hike, they stopped to “take a break, get the map, and see if we can find out exactly where we are,” as Mitchell said. As they caught their breath, they thought they’d sorted out their location. They were wrong.

Shepard and Mitchell took turns pulling the cart, which NASA—sweet on convoluting the labels for its gear and infatuated with acronyms—called a Modular Equipment Transporter,��or MET. Keeping it from toppling on the uneven ground slowed them. As the slope steepened, they picked up the MET and carried it, certain they would end their climb at Cone Crater’s rim. When they reached the top, however, they found a swale ahead, and beyond it, another rise. The crater, more than a thousand feet wide, was nowhere in sight. “Well,” a baffled Shepard told mission control, “we haven’t reached the rim yet.”

“Oh��boy,” Mitchell said. “We got fooled on that one.”

Apollo 15 commander Dave Scott maneuvers the rover before he and Jim Irwin set out on their second drive, in August 1971. (Courtesy NASA, scan by Kipp Teague)

So they marched on, pulling and carrying the MET, ascending another steep rise, growing more tired and frustrated by the minute, and steadily depleting the stores of air and cooling water in their backpacks. Their transmissions were breathless, and at times their heartbeats—especially 47-year-old Shepard’s—spiked to the point that Houston urged them to take a break. This climb, too, ended in disappointment. “It’s going to take longer than we expected,” Mitchell reported. “Our positions are all in doubt now.”

They were not lost. They could see Antares behind them; getting back to safety was never an issue. But experiments on Earth had shown that an impact crater’s debris, or ejecta, is arranged around the hole in a predictable pattern, with the material from deepest underground closest to the rim—and that if they wanted to sample lunar bedrock, which was a mission priority, they had to get near that edge. They came to another long slope, which Shepard figured would take 30 minutes to crest. “I don’t think we’ll have time to go up there,” he told Mitchell.

“Oh, let’s give it a whirl,” his partner countered. “Gee whiz. We can’t stop without looking into Cone Crater.” They had to be close, wherever they were, and he was confident they would “find what we’re looking for up there.”

Houston came on the radio. Given how discombobulated the astronauts seemed to be, mission control wanted them to consider the spot where they stood to be the crater’s rim, and to collect samples there. Mitchell, exasperated, called their handlers “finks.” Shepard tried to assuage him. “I think what we’re looking at right here, in this boulder field, Ed, is the stuff that’s ejected from Cone.”

“But not the lowermost part,” Mitchell replied, “which is what we’re interested in.”

“OK,” Shepard said. “We’ll press on a little farther, Houston.”

Mission control extended their allotted time for the search by 30 minutes. The men��trudged uphill. When the ground leveled out, they were not looking down into Cone, however, but just another shallow valley in Fra Mauro’s wrinkled surface. By that time, they’d cut deep into their extra half-hour. Houston had them sample rocks and soil there, then start back.

Irwin straightens up the Apollo 15 rover after its first run. (Courtesy NASA, scan by Kipp Teague)

Skip ahead to the last day of July��and Apollo 15’s first traverse of the mountainous Hadley-Apennine region by lunar rover. Dave Scott and Jim Irwin had a much more ambitious assignment than their predecessors: to cross a mile of hummocky, cratered plain to a spectacular gorge called the Hadley Rille, then follow its edge to the foot of a mountain that, in sheer mass, rivaled the biggest massifs on Earth—and climb a portion of its side.

After unfolding the rover from its bay in their lunar module, Falcon, they loaded it with a TV camera, antennas, and geologic tools, then set off at the equivalent of a fast jog, Scott controlling the contraption with a T-shaped joystick. Thirteen minutes into their ride, they reached the rille, nearly a mile wide and a thousand feet deep.

They’d already covered twice the distance��from Antares to the Cone Crater. And though piloting the rover involved some “sporty driving,” as Scott told Houston, they were untaxed by the journey. In contrast to the Apollo 14 crew’s wheezy transmissions, the Apollo 15 explorers engaged in relaxed, almost breezy, conversation—and their lower metabolic rates translated into slower consumption of air and water, stretching the time they could spend outside. They drove along the canyon’s lip until they were two straight-line miles from Falcon, and stopped alongside Elbow Crater, timeworn and 1,100 feet wide, the site of their first geologic investigation.

Mission control remotely started the rover’s TV camera. During Shepard and Mitchell’s slog at Fra Mauro, the stationary camera back at Antares had stared out over motionless landscape; the only change in the picture was a slow, subtle shift in the scene’s lighting as the sun crawled higher in the sky. This time, viewers on Earth watched Scott and Irwin in real time as they conducted science in the field, bagging samples and taking pictures.

They left Elbow Crater for the mountain, Hadley Delta, which rose 12,000 feet above the plain. The rover outperformed its meager horsepower: when the men stepped off the machine, 2.4 miles from base camp, they were surprised at how steep the ground felt under their boots—and by the fact that, almost without realizing it, they’d climbed 220 feet up the mountain’s flank. They now had a commanding view of the plain and canyon below. “Oh, look at that,” Scott said. “Isn’t that something? We’re up on a slope,��and we’re looking back down into the valley, and—”

“That’s beautiful,” Irwin said.

“That is spectacular,” Scott agreed. He readied the rover’s umbrella-shaped high-gain antenna for TV transmission, then paused for another long look. “The most beautiful thing I’ve ever seen.”

They spent 45 minutes sampling rocks and soil before heading back downhill, following a course for base camp laid by the rover’s navigation system. It worked as designed, so that they were always pointed back to safety.

Apollo 16 commander John Young uses an eyepiece to aim the second rover’s high-gain antenna, which carried live TV signals to Earth. (Courtesy NASA, scan by Kipp Teague)

Young holds a sample bag as he prepares to gather rocks during his third extravehicular activity with astronaut Charlie Duke, in April 1972. (Courtesy NASA, scan by Kipp Teague)

People had been thinking about driving on the moon for most of the century, although the bulk of those thoughts were embedded in science fiction. One description of a pressurized moon��mobile cruising the lunar surface dates to 1901. Others were imagined��regularly in the decades after—rolling spheres, cigar-shaped runabouts, walkers and crawlers, tanklike transporters.

In May 1961, when President John F. Kennedy challenged the nation to “commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to Earth,” NASA embraced the idea for real. Early concepts included hulking laboratories on wheels, which astronauts would pilot in shirt-sleeved comfort on two-week odysseys—contraptions so big and heavy that they’d have required their own Saturn V rockets to reach the moon’s airless wilds.

When even an open “lunar jeep” proved too bulky for one-rocket missions, NASA shelved the project in 1967, believing it would cost too much time and money to pull off for Apollo flights. But in the months that followed, Ferenc “Frank” Pavlics, an enterprising engineer at a General Motors defense lab in Santa Barbara, California, came up with a more radically downsized approach—a tiny, minimalist moon car that weighed little more than a single astronaut in his space suit��and could be origamied to fit into an existing storage bay in the lunar module, a space about the size and shape of a pup tent standing on its end.

The resulting machine, built by Boeing with GM as its principal subcontractor, was hurried through design, testing, and manufacturing in only 17 months, a fraction of the time typically devoted to NASA hardware. The job proved deceptively complex: its cost mushroomed to more than twice Boeing’s bid, and at times it lagged so far behind schedule that the first of the cars seemed sure to miss its ride on Apollo 15.

The companies met their deadline, however, and delivered a quintessential example of doing more with less. The LRV ran on two silver-zinc batteries that powered its four quarter-horsepower electric motors, each of which was connected to a transmission with just two moving parts. It boasted a crazily limber suspension and could turn in its own length. It could carry well over twice its own weight. Its top speed of about ten miles per hour might sound glacial, but on the moon’s broken crust, it usually could go faster than its drivers dared take it.

The rover’s signature features—its wheels—were studies in elegance: each tire was made of 800 strands of zinc-coated stainless-steel piano wire, woven into a mesh and mounted to a 16-inch, spun-aluminum hub, all of it armored by a herringbone tread of titanium strips. The complete wheels weighed 12 pounds apiece. Earth pounds.

And despite its gossamer construction, this was a tough little 4×4. “We did a lot of testing—vibration tests, temperature tests to the extremes of temperatures, and, of course, durability,” Pavlics told me. “Simplicity and light weight were overall considerations. Of course, reliability had to be very high: NASA set a goal of 99.5 percent reliability. So we included redundancy wherever possible—like all four wheels had a drive in them, so that if one or even two failed, it was still operational. The steering was in both the front and rear, so that, again, if one fails, the other is still there.”

The payoff: when Scott and Irwin braked their rover to end their first excursion, two hours and 16 minutes after its start, they had covered 6.3 miles—more than all the travel achieved by the first three landing crews combined.

They still had two sorties to go. The next day, they drove back up the side of Hadley Delta to discover a nugget of anorthosite more than four billion years old, prompting their mission-control flight director to call August 1, 1971, “the greatest day of scientific exploration, certainly, that we in the space program have ever seen—and possibly of all time.”

Eight months later, in April 1972, Apollo 16’s lunar module Orion came to rest on the Descartes Highlands, and astronauts John Young and Charlie Duke took off in the second rover. They crossed more than 16 miles of jumbled moonscape��and climbed even higher up a mountainside. Along the way they collected geologic evidence refuting scientific gospel that the highlands were volcanic in origin.

Duke recalled his time riding shotgun as a thrilling adventure. “It was bouncy” and a bit “squirrely, like driving on snow and ice,” he told me 48 years after the fact. “We had a very rough terrain where we landed—it was up-and-down, cratered everywhere, rocks of various sizes all over the surface. So we had to do a lot of maneuvering around rocks, craters, and crevasses.

“If you had both steering systems energized, it was very maneuverable,” he said. “If anything, the steering was maybe a little too sensitive. We’d be underway, and I’d turn in my seat to get a side picture��and I’d bump John’s elbow, and that would��change his steering, and then he’d start fishtailing as he tried to get it back under control.”

That said, the pair hated to leave their trusty steed behind when they left for home. Young’s last photo on the lunar surface was “of the old rover sitting there,” as he put it to Houston, adding: “Boy, that’s a good machine.”

“Yeah,” Duke chimed in, “it’s an incredibly good machine.”

Gene Cernan poses beside the rover during the Apollo 17 landing crew’s stay on the moon. (Courtesy NASA, scan by Kipp Teague)

Finally, on the last lunar mission, the Apollo 17 crew drove up and over a ridgelike fault that rose high above the moon’s Taurus-Littrow Valley, then rolled down the other side. When astronauts Gene Cernan and Jack Schmitt stopped at the bottom to gather rock samples, they were just shy of five miles from their lunar module, at the outer limit of their safe radius of travel.

No other explorer has ever been in circumstances so remote��or in hazards so extreme. The moment the two climbed off their rover—at 8:36 P.M. EST on Tuesday, December 12, 1972—marked a pinnacle in the annals of exploration. An expedition had never before, and has never since, pushed adventure farther or further. The astronauts were out at the edge of the edge��of man’s travels as a species; by comparison, Roald Amundsen’s trek to the South Pole was a run to the corner grocery.

All told, astronauts on the last three lunar visits drove more than 56 miles. The wanderings of the moonwalkers on the first three landings would fit into half of New York City’s Central Park. Each of the rovers was capable of covering an area the size of Manhattan. The machines gave crews not only range, but deepened the science they undertook: of the 842 pounds of geologic samples collected on the six Apollo landings, nearly three-quarters—about 620 pounds—were gathered on drives in the LRVs.

“The rover revolutionized lunar explorations,” Duke told me. “That’s for sure.”

Most Americans, it seems safe to say, cannot identify those last three landing parties, which is frustrating testament to our short attention spans. But the astronauts’��names should be known alongside those of Armstrong and Aldrin; the total of��nine days they spent��on the moon were a fitting culmination to Apollo��and a half��century later remain the crowning accomplishment of America’s manned space program. Their success would have been beyond reach—literally—without the wispy contrivance that carried them.

Which must be admired from afar. A handful of exact rover copies, built for testing, are available for earthbound inspection at several U.S. museums. The three actually sent to the moon remain there, along with a scattered junkyard of other Apollo detritus.

Anyone who still doubts that America sent men to the moon—and a few of those people still walk among us, even at this late date—need only go online to find overhead photos of the six landing sites, taken in 2011 by NASA’s Lunar Reconnaissance Orbiter. In surprising detail, they show the descent stages of the lunar modules, surrounded by scientific gear.

And at three of the base camps, there are the rovers, just as their drivers parked them.

Plainly visible all around, and stretching for miles across the lunar wastes, are tire tracks.

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Lead Photo: Courtesy NASA, scan by Kipp Teag

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The Off-Roading Astronauts of Apollo

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