Taking the Moon Buggy for a Spin

Today it feels like science fiction, but more than 45 years ago humans were taking a six-hour drive on the surface of the Moon.

Apollo 15 astronauts James Irwin and David Scott debuted the Lunar Roving Vehicle (or ‘Moon Buggy’ as it’s familiarly known) on 31 July 1971, just a few hours after they became the fourth mission to land on the Moon. They drove a total of 27 km over three separate journeys, allowing them to explore far more of the Moon’s alien landscape than all previous missions.

This week is the anniversary of that historic drive.

Science Fact or Fiction?

By 1969, when Apollo 11 astronauts Neil Armstrong and Buzz Aldrin were taking their first tentative steps on the Moon, NASA was already looking ahead to longer lunar missions.

Neil and Buzz explored less than the length of a football pitch during their day-long visit. Clearly this wouldn’t cut it when the whole of a new and alien lunar world was ripe for scientific exploration and discovery. A car was needed.

But how to develop a car that would work on the Moon? When NASA engineers were exploring concepts for the Lunar Roving Vehicle, they naturally turned to the past fifty years of science fiction writing for inspiration.

Long before NASA was even conceived, science fiction writers were designing cars for the Moon. Polish writer Jerszy Zulawski imagined a pressurised cabin with interchangeable wheels and claws in his 1901 novel On the Silver Globe (Szrebyym Globie). Rocket engineer Wernher von Braun predicted giant tractor trailers for carting supplies across the Moon in the early 1950s. Other ideas were more fanciful and included vehicles walking on two robotic legs.

These writers imagined people living and working on the Moon for extended periods of time and naturally saw the need for transport.

“The visible part of the Moon extends over an area twice the size of the United States — and the far side of the moon is just as large,” wrote von Braun in 1964 for Popular Science. “As there are no superhighways on the moon (yet), all vehicles must have cross-country capability. Just as on Earth, the terrain on the moon is partially smooth and flat, while other parts are rugged and mountainous.”

In the same article, von Braun predicted an open-top ‘Moon jeep’ for short journeys, very similar to the Lunar Roving Vehicle that was ultimately sent to the Moon.

The Challenge

Your challenge, should you choose to accept it:

Design a car that can drive on an unknown terrain – sometimes a fine powder, sometimes a steep and rocky crater – in one-sixth Earth’s gravity, no atmosphere, and temperatures that range from plus or minus 250^oF. The car must be light-weight and foldable for launch, but durable enough to carry more than twice its own weight including two astronauts, their cameras, equipment, and any rocks they collect on route. The car must also be battery powered and travel at 16 km/hr.

Oh, and this car needs to be ready in just eighteen months.

This was the tall order that NASA set in May 1969. But engineers at the NASA Marshall Space Flight Center in Alabama took on the challenge with relish. NASA’s Brief History of the Lunar Roving Vehicle comments that “inventing a car for drivers on the moon was as appealing to a grown-up’s imagination as to a child’s.”

Over the next year and a half, NASA worked with engineers at Boeing in Washington state to build eight lunar rovers – four for the Moon (being lighter and more fragile than the test rovers since they operated in much weaker gravity), and four for testing and training.

The Apollo astronauts practised unloading, unfolding, and driving the test rovers in full space suits and in rocky deserts in New Mexico. They even mounted one in the ‘Vomit Comet’ plane and practised getting in and out in while the plane flew in steep arcs to simulate weak gravity.

Meanwhile the engineers vibrated, heated, and tested the rover in every possible way before launch. This vehicle had to work perfectly first go; there would be no test run on the Moon. If it didn’t work, the astronauts would be extremely limited in terms of the range of lunar landscape and geology they could sample – a heart-breaking concept to scientists anxious to sample an alien landscape as old as the Solar System itself.

Luckily the Lunar Rover performed better than expected on every mission.

As astronaut and scientist Harrison Schmitt of Apollo 17 said, “Without it, the major scientific discoveries of Apollo 15, 16, and 17 would not have been possible; and our current understanding of lunar evolution would not have been possible.”