The First Lunar Road Trip
James Irwin and the LRV, on July 31, 1971. Image: David Scott/NASA

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The First Lunar Road Trip

Celebrating the debut of the Lunar Roving Vehicle, 45 years on.

1971 was a great year for the glorification of vintage American road trips. Hunter S. Thompson published Fear and Loathing in Las Vegas, the Route 66 film Two-Lane Blacktop was released, and some of the Grateful Dead's early "Road Trips" albums were recorded.

But despite all that competition stateside, the coolest American road trip of 1971 did not take place within the borders of the US. In fact, it didn't even take place on the planet. On July 31, 1971, Apollo 15 astronauts David Scott and James Irwin took NASA's sweetest set of wheels out for a spin on the Moon.

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Setting out at 9:13 AM Eastern US time, the two men enjoyed a lovely Saturday drive through the lunar countryside, with sightseeing stops along the way. Their ride, NASA's Lunar Roving Vehicle (LRV), was a "brilliant piece of engineering with sealed electric motors in the hub of each wheel," according to Two Sides of the Moon, Scott's joint autobiography with Russian cosmonaut Alexey Leonov.

The trip was undertaken at the breakneck pace of six miles per hour, and marked the first time anyone had driven an automobile off Earth. Scott said this extreme offroading trip felt like "a cross between a bucking bronco and a small boat in a heavy swell."

"Driving the rover was actually more like flying an airplane, albeit with four wheels, than driving a car," Scott said. "Instead of a steering wheel, which would have been very difficult to grasp in our bulky suits, it was controlled with a joystick mounted on a control console between my seat and Jim's. Despite our maximum speed of only seven or eight mph, the reduced gravity and very irregular surface meant one or more of the independently suspended wheels lifted away from the surface every time we hit uneven terrain."

"Driving into the Sun was the most difficult, since the glare caused a 'wash-out' of the surface features," he continued. "Though the rover could turn on a dime and had very good traction and power, the wire-mesh wheels kicked up impressive rooster-tails of dust, which were deflected by large fenders."

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On top of all that, Scott and Irwin must have been acutely aware that if they totaled their moon buggy, there would be no roadside assistance to help them get back to base. For that reason, the pair were instructed to drive only as far as they could walk with the oxygen in their life support systems, just in case the LRV broke down.

Over the course of six hours and 33 minutes, Scott and Irwin completed a southern traverse of about 5.6 miles around the Hadley–Apennine region of the Moon, located on the eastern edge of the massive Mare Imbrium crater (aka the right eye of the Man in the Moon). They hit up Elbow and Saint George craters along the way—picking up samples, taking pictures, and filming their activities—before heading back north to the Apollo 15 Falcon lunar module (LM). They subsisted on fruit sticks that had been packed into pouches below their chins during the drive.

For the most part, every detail of this inaugural interplanetary drive was heavily scrutinized by Mission Control in Houston. But Scott cheekily managed to get one "off the record" stop in on the way back to the Falcon.

"Once, when Houston prompted us to get moving and head home," he recounted, "I was so determined to pick up a very interesting black rock, which I could see not far away sitting all alone on the gray surface without a speck of dust, that I had to resort to subterfuge."

"I stopped the rover and pretended to adjust Jim's seatbelt so that I could stoop to pick it up. This beautiful rounded piece of scoriaceous basalt was later dubbed the 'seatbelt basalt.'"

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Irwin hammed it up over the radio to Mission Control, to help buy his commander the time he needed to grab the rock. It's worth taking a look at the transcript of that moment to grasp the sheer scampiness of this mad basalt caper. Here's part one, featuring the "wink wink" moment between Scott and Irwin and their efforts to distract Joe Allen at Mission Control.

Scott: Oh, there's some vesicular basalt right there, boy. Oh, man! Hey, how about…? Let's just hold on one second, we've got to have…
Irwin: Okay; we're stopping.
Scott: Let me get my seatbelt.
Allen: Roger; mark that you stopped.
Scott: It keeps coming off.
Irwin: Why don't you hand me your seatbelt?
Scott: Just a minute.
Irwin: Then get off. (Pause)
Scott: If I can find it. (Pause) There it is. (Pause) If you'll hang on to it here for a second.
Irwin: Okay, I've got it. (Long Pause)
[Unbeknownst to Houston, Dave has stopped to pick up a piece of the basalt.]

You have to love the unbridled enthusiasm with which Scott first acknowledges the rock, and the conspiratorial pauses that follow. But it only gets better from there.

Allen: And are you moving again?
Irwin: No, we're stopped here, Joe. I'll let you know when we move.
Allen: Roger. (Long Pause)

Irwin: You know, Joe, these small fresh craters that we've commented on, whatever caused them must create […] or indurate the soil into the rocks (that is) creates its own rocks (regolith breccia), because there's just a concentration of rocks around the very fresh ones (craters). And by 'small' I'm talking about may be a foot to three feet diameter.

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Allen: Rog, Jim. Sounds very plausible.
Irwin: …And create the (lost under Joe) breccia.
Scott: Okay, ready to hand me my (seatbelt)…
Irwin: Yeah. (Pause) Get it (probably the piece of basalt)?
Scott: Yep. (Long Pause)
[Dave has finished getting the sample and is getting seated. The sampling has probably taken about a minute and 40 seconds.]

The way Irwin casually diverts Allen's attention by expounding on his surroundings is pretty hilarious in retrospect. The secretly obtained basalt was not discovered until Apollo scientists stumbled on it in the mission's rock boxes, prompting Scott to fess up to his hijinx.

Of course, that was not the only time the Apollo 15 crew bent the rules a little. A more famous example is the postage stamp scandal that erupted in the wake of the astronauts' return, when it was discovered that the men had taken unauthorized stamp covers to the Moon, for resale.

But for the most part, the mission that debuted the first lunar road trips was so productive that NASA called it the "most successful manned flight ever achieved" at the time. Scott and Irwin took the LRV out for two more drives on August 1 and 2, notching the rover's odometer up to a mission total of 27.8 kilometers (17.3 miles).

In an era when road trips were becoming the trendiest way to explore our planet, the adventurous crew of Apollo 15 took the tradition to the next level.