It looked like a motorized bed and drove about as well, but the Lunar Rover’s exploits on the Moon’s surface more than 30 years ago made it one of the most celebrated modes of personal transportation ever to be built.
As the star of the last three missions to the moon, the Rover provided the means for six intrepid adventurers — two per mission — to traverse the lunar landscape, collect rocks and soil samples and beam their experiences directly into our homes.
For TV viewers, watching the Rover bound over boulders and craters while churning up swirls of moon dust provided plenty of thrills as well as a strong dose of national pride.
Talk about a niche vehicle.
There were actually only three Lunar Roving Vehicles (LRV) built for off-roading across the zero-oxygen, low-gravity, extreme-temperature surface of the Moon, one for each of the last three Apollo journeys that ever so slightly pushed back the boundaries of space.
Each was used for mere hours over the course of three days and travelled no further than a typical commute to work. But the Rovers were indispensible in moving two of the three-man astronaut teams (a third astronaut remained inside the main capsule as it orbited the Moon) across vast tracts of colorless topography.
The span from November, 1969, to April of 1971 — 17 months, to be exact— wasn’t much time to develop something as complex as the Lunar Rover, but it was all that Boeing was given to produce a specially strengthened model for practice on earth as well as deliver the first flight-ready example to the Kennedy Space Center in Florida.
The design challenges were based on size (dimensional constraints of the small-for-the-time space craft), weight (every extra pound meant more fuel to break the earth’s atmosphere) and the ability for a fast setup (due to limited mission duration and life-support systems).
With moon temperatures ranging from -279 F in the shade to +243 F in the sun, it was obvious that a conventional liquid-gasoline engine was out of the question. The Rover’s propulsion system consisted of two 36-volt silver-zinc batteries (one for backup) that supplied current to the one-quarter-horsepower motors located at each of the machine’s four wheels. In the event of a failure, the remaining electric motors could keep the LRV operational. Each battery had a projected life of 78 hours to give a range of about 40 miles.
For traction, the Rover came with 32-inch-tall tires made from piano wire with a series of titanium cleats as tread. (They were much lighter than regular passenger-car wheels and rubber tires.)
With a fully loaded top speed of just eight m.p.h., the Rover was slow, but it sped up the mission at hand and also conserved the astronaut’s extra-vehicular life-support systems.
Instead of operating with a traditional steering wheel, the LRV used a T-shaped hand controller positioned between its two lawn-chair-style seats which allowed either of the two occupants to drive the vehicle, golf-cart style.
Equipped with four-wheel steering, the Rover could turn on a radius that was equal to its length. And to tackle roadless terrain of the moon, the LRV was designed to have enough power to climb a 25-degree slope and traverse a 35-degree grade without tipping over.
In the end, the final design was just 10-feet long, six-feet wide, had 14 inches of ground clearance and weighed 480 pounds, or a mere 80 pounds — one-sixth — on the Moon. For easy transport, it was folded in three places and stowed inside the lunar landing module.
Once assembled, the crew attached a color video camera, umbrella-shaped antenna plus assorted tools, sample bags, cameras and other necessities for conducting experiments. Once the team arrived at its destination, the antenna would be pointed toward earth and the camera (remotely operated from the Manned Spacecraft Center, later renamed the Johnson Space Center in Houston, Tex.) would track them as they worked.
On July 26, 1971, the giant multi-stage Saturn V rocket blasted off from its Florida launch pad, carrying Apollo 15 astronauts David Scott, James Irwin and Alfred Worden along with their LRV. Five days later, Scott and Irwin took the first of three drives on the Moon, racking up nearly 17 miles without a hitch. Within the next year-and-a-half, two more teams of two astronauts, part of the Apollo 16 and Apollo 17 missions, would drive similar Rovers and continue to astonish us with their exploits.
At more than $40 million (double the original budget) the cost brought into question the need for such seemingly glamorous hardware. However, as each of the three vehicles performed their jobs with near flawless precision, complaints about the cost quickly subsided.
Today, their tasks long since completed, all three of these amazing off-earth utility vehicles silently sit at different sites on the Moon’s surface, parked a short distance from each Lunar Module’s descent stage.