What was the history, development and use of the lunar rover?
When you think of humanity’s exploration of the Moon, your mind might automatically picture… well… humans. Like, say, Neil Armstrong, who touched down on July 20th, 1969 with the famous phrase, “That’s one small step for man, one giant step for mankind.”
But our lunar endeavors have led to “one giant step” for manmade vehicles, as well. In this article, I’ll delve into the history, development and use of NASA’s Lunar Roving Vehicle – or “lunar rover”, for short.
The impetus for the rover came out of a written statement from noted scientist Wernher von Braun. In the February 1964 issue of Popular Science, von Braun gave the rover its first real legs as a workable concept. He discussed what he called a “lunar surface vehicle”, saying:
“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. 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.”
Eventually, the design company Boeing was given a contract to construct a “lunar rover” type vehicle. They began construction in 1970, expecting to finish a usable rover in 1971.
While designing and developing the rover, Boeing kept in mind six crucial systems: movement, power, navigation, communications, heat protection and crew placement.
The rover’s exceptional movement features were its tires. So that the rover could cut through the Moon’s soft, powdery soil, Boeing gave its tires a specialized wire mesh. And the rover can perhaps be thought of as a precursor to today’s hybrid vehicles. For Boeing gave it two 36-volt silver zinc batteries, with electric motors powering each of its four wheels.
The rover’s navigation system contained several features that helped astronauts get around the Moon. It combined a gyroscope and odometers to tell astronauts the precise direction they were from their starting point (the lunar module) and precisely how far away they were from that point. And the rover also was able to communicate with NASA’s Houston HQ. It contained both a television feed and radio-communication equipment that streamed data on both the astronauts and the rover itself.
Since the rover was going to be used on the Moon, it was going to be subject to wild temperature variances – and it also had to account for the heat that its own machinery created. Boeing designed it with these two factors in mind. Specific pieces of the rover actually stored and collected equipment-generated heat during expeditions, with astronauts releasing this heat after the expedition had concluded. (Ideally, the entire rover would be “open”, and heat could then dissipate into the atmosphere. But this wouldn’t work on the Moon – lunar dust would fill up the openings and disrupt the equipment.)
Finally, the rover’s crew station resembled “webbed patio furniture”. Its astronaut drivers sat within nylon enclosures. Either of the two could operate the specialized hand controller that lay between them; notably, this controller only required one hand. It handled the rover’s speed, braking and steering, allowing for extremely tight turns.
While Boeing manufactured four “flight-ready” rovers, NASA only used rovers on three Moon missions – Apollo 15, Apollo 16, and Apollo 17.
Each time, the rover’s “traverse” was hampered by the “Walkback Limit” – the maximum distance that the astronauts could travel from the lunar module. If the rover was to move outside of this distance and then break down, the astronauts could then not conceivably walk back to the module. (Hence, the name “Walkback Limit”.) Said limit was at its most “relaxed” during the Apollo 17 traverse.
On the rover’s Apollo 15 mission, the astronauts (Commander David Scott and Lunar Module Pilot James Irwin) spent three hours and two minutes driving the rover. They drove a total of 17.25 miles, with 7.75 miles of that in a single traverse. This mission’s “Walkback Limit” was 3.1 miles.
On its Apollo 16 mission, the astronauts (Commander John W. Young and Lunar Module Pilot Charles M. Duke, Jr.) spent three hours and twenty-six minutes in the rover. They drove 16.50 miles, with 7.20 miles of that in one traverse. This time, the “Walkback Limit” was 2.8 miles.
And on the rover’s final mission, Apollo 17, the astronauts (Commander Eugene A. Cernan and Lunar Module Pilot Harrison H. Schmitt) spent four hours and twenty-six minutes in the rover. They drove 22.30 miles, with 12.50 of those miles in one traverse. And the “Walkback Limit” was 4.7 miles.
Note the serious upgrades between Apollo 16 and Apollo 17 – a thirty-five-plus percent increase in driving distance, a nearly thirty percent increase in driving time, a seventy-plus percent increase in the maximum traverse, and a sixty-five-plus percent increase in “Walkback Limit”. I believe these upgrades indicate a level of increased comfort with the rover and its capabilities.
(The Rover on its Apollo 17 mission.)
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