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Speaker 1: This Day in History Class is a production of iHeartRadio.

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Speaker 1: Hello and Welcome to This Day in History Class, a

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Speaker 1: show for those who can never know enough about history.

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Speaker 1: I'm Gabe Lucier, and in this episode, we're looking at

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Speaker 1: a banner day for American car culture, the time when

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Speaker 1: astronaut explorers traded in their rockets for a brand new

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Speaker 1: set of wheels. The day was July thirty first, nineteen

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Speaker 1: seventy one. NASA astronauts drove a lunar roving vehicle on

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Speaker 1: the Moon for the first time. The two man crew

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Speaker 1: had landed at the Moon's Hadley Rill one day earlier,

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Speaker 1: and after getting a good night's sleep aboard the Falcon

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Speaker 1: lunar Module, it was finally time to get behind the

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Speaker 1: wheel and go for a spin. The Apollo fifteen mission

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Speaker 1: was the fourth time that a NASA team had successfully

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Speaker 1: landed on the Moon, making crew members Commander Dave Scott

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Speaker 1: and Lunar Module pilot Jim Irwin the seventh and eighth men, respectively,

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Speaker 1: to ever walk on its surface. But even more notably,

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Speaker 1: they were the first humans to experience driving on a

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Speaker 1: world other than our own. This was no mere joy ride, though,

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Speaker 1: the lunar roving Vehicle or LRV, was included on the

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Speaker 1: mission as a way to extend the astronaut's travel range,

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Speaker 1: allowing them to venture farther from the landing site and

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Speaker 1: to collect a greater variety of rock and soil samples.

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Speaker 1: Over the course of three excursions, the Apollo fifteen astronauts

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Speaker 1: spent eighteen and a half hours in the rover, traversing

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Speaker 1: a distance of about seventeen miles and collecting one hundred

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Speaker 1: and seventy pounds of samples along the way. One of

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Speaker 1: the most significant items collected during their journey was the

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Speaker 1: so called Genesis Rock. Geologists believe it to be a

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Speaker 1: piece of the Moon's primordial crust, and later concluded that

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Speaker 1: it was roughly four billion years old. The Genesis Rock

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Speaker 1: provided valuable insight on the Moon and its origins, but

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Speaker 1: its collection never would have been possible if not for

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Speaker 1: the lunar rover. Apollo fifteen was the first of three

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Speaker 1: Apollo missions to make use of lunar rovers. Those missions,

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Speaker 1: dubbed j missions, were more science focused than previous ones

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Speaker 1: had been and were designed to allow for longer stays

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Speaker 1: on the Moon. In addition to geologic sample collection, experiments

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Speaker 1: included surface photography, soil investigations, and a solar wind composition experiment,

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Speaker 1: all of which were facilitated by the LRVs onboard equipment

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Speaker 1: and communications gear. Although a rover had been planned for

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Speaker 1: inclusion on earlier Apollo missions, weight limitations and other factors

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Speaker 1: had delayed the project until Apollo fifteen. That need for

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Speaker 1: extra development time makes sense when you consider what a

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Speaker 1: logistical challenge the designers were up against. The Moon's lack

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Speaker 1: of atmosphere, diverse topography, and very slight gravity left the

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Speaker 1: engineers with a vast range of variables to account for,

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Speaker 1: and with no terrestrial experience to draw from. The final

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Speaker 1: design of the rover was a four wheel, lightweight vehicle

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Speaker 1: powered by four separate electric motors. It was something we

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Speaker 1: would casually refer to today as a Moon buggy. Despite

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Speaker 1: tipping the scales at four hundred and seventy pounds on Earth,

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Speaker 1: the rover weiight to trim eighty five pounds on the

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Speaker 1: lunar surface due to the Moon's low gravity. This allowed

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Speaker 1: crew members to easily lift, move, and tow the LRV

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Speaker 1: using a series of hand holds built into its aluminum

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Speaker 1: alloy frame. The rover could be operated by either astronaut,

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Speaker 1: but in practice it was only ever driven by the

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Speaker 1: mission's commander, Dave Scott, a fact that you have to

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Speaker 1: imagine bugged Jim Irwin at least a little, though to

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Speaker 1: be fair, he still had one up on Command module

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Speaker 1: pilot Alfred Warden, who was stuck orbiting the Moon while

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Speaker 1: Irwin and Scott piled around on its surface. The operation's

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Speaker 1: handbook for the LRV included instructions for several minor repairs

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Speaker 1: should they be needed, including fixes for problems with the brakes,

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Speaker 1: steering system, and wheels which were made of wire mesh

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Speaker 1: rather than inflatable rubber. However, the handbook had one chilling omission.

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Speaker 1: There were no written instructions for what to do if

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Speaker 1: the rover were to break down completely. Instead, NASA simply

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Speaker 1: instructed the astronauts to never drive beyond a point from

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Speaker 1: which they couldn't walk back. This ensured that should the

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Speaker 1: LRV stop working while far away from the lunar module,

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Speaker 1: the astronauts would still be able to return on foot

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Speaker 1: without a exhausting their portable life support systems. Thankfully, they

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Speaker 1: never had to test that theory, as the LRV performed

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Speaker 1: like a champ throughout the mission. Before leaving the lunar

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Speaker 1: surface on August second, Commander Scott conducted one final experiment.

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Speaker 1: It was meant to test Galileo's theory that objects in

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Speaker 1: a vacuum would fall at the same rate regardless of

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Speaker 1: their mass. To that end, he dropped a geological hammer

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Speaker 1: and a feather, and when both objects hit the ground

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Speaker 1: at the same time, Galileo was proven right. To mark

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Speaker 1: the achievement of mankind's first car ride on the Moon,

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Speaker 1: the Apollo fifteen rover had been outfitted with a plaque

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Speaker 1: which read Man's first Wheels on the Moon, delivered by

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Speaker 1: Falcon July thirtieth, nineteen seventy one. If you'd like to

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Speaker 1: see that historic artifact for yourself, you'll first need to

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Speaker 1: sort out your own passage to the Moon, because the

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Speaker 1: plaque and the rover are still up there to this

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Speaker 1: very day. I'm Gabe Lucier and hopefully you now know

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Speaker 1: a little more about history today than you did yesterday.

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Speaker 1: You can learn even more about history by following us

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Speaker 1: on Twitter, Facebook, and Instagram at TDI HC Show, and

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Speaker 1: if you have any feedback you'd like to share, you

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Speaker 1: can send it along any time by writing to this

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Speaker 1: day at iHeartMedia dot com. Thanks to Chandler Mays for

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Speaker 1: producing the show, and thank you for listening. I'll see

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Speaker 1: you back here again tomorrow for another day in history

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Speaker 1: class