These astronauts bopped around Cape Canaveral in a phalanx of distinctive red, white, and blue corvettes while training for Apollo 15, but their true pride and joy was the very first lunar rover.
The crew of the Apollo 15 moon landing were a distinctive group, working patriotic colours into everything from their personal vehicles to the stylized birds on their mission patch. The US Air Force astronauts Jim Irwin, Dave Scott, and Al Worden were clearly proud of their country by their coordinated colour set of red, white, and (dark) blue corvettes (which were apparently the sensible alternative to NASA renting vehicles for them to use around Cape Canaveral), but their true pride and joy was the lunar rover. The crew of Apollo 15 had the first moon buggy, the first vehicle to be sent off-planet in a quest to give astronauts greater range while exploring the moon.
The Apollo 15 mission patch features a stylized bird representing each astronaut (Irwin in red and Scott in blue on the surface, with Worden in white above in orbit) on a backdrop of the landing site (Hadley Rille at the foot of the Appenine Mountains) with craters spelling out the mission number (XV). Image credit: NASA
Artist’s concept of Jim Irwin and Dave Scott navigating the boulders along the rim of Hadley Rille. Note the landing module in the background is unrealistically close to the mountains. Image credit: NASA
Apollo 15 was the first lunar landing mission to use a rover, allowing astronauts Jim Irwin and Dave Scott to explore farther from their landing site while still having time to conduct scientific research. Al Worden stayed in orbit, photographing a quarter of the moon’s surface during his three solitary days in a spacecraft in July 30 to August 2, 1971.
Jim Irwin and Dave Scott pose with the training Rover, while Al Worden keeps a hand on the subsatellite that he would release into lunar orbit. Image credit: NASA
Apollo 15 marked the start of serious geological training for astronauts. Irwin and Scott underwent extensive fieldwork, including using a geological rover (“Grover”) as part of their training. Worden’s training for lunar mapping while in alone in orbit involved flying over new terrain to practice the fine art of geomorphological interpretation from above.
Jim Irwin and Dave Scott practicing their new geology skills while driving the Grover along the rim of the Rio Grande Gorge in Taos, New Mexico in March 1971. The ravine was approximately the same width as Hadley Rille, their scientific target on the moon. Image credit: NASA
The rover had been in development since May 1969, and was first flown on during the Apollo 15 mission from July 26 to August 7, 1971. Boeing ultimately delivered four rovers. One each was used for Apollo 15, 16, and 17, while the final rover was disassembled and used for spare parts after the cancellation of continued human missions to the moon.
Actual lunar rover at the Boeing plant just prior to packing and shipping. Image credit: NASA
The rover was incredibly compact, folding into just 1.5 by 0.5 meters (5 feet by 20 inches) for stowage on the lunar landing module. Yet, once unfolded, it was a spacious 3.1 meters (10 feet) long on a 2.3 meter (7.5 feet) wheelbase. The aluminum alloy frame consisted of 2,219 welded tube assemblies in a 3-part chassis hinged in the center to tuck neatly into the quad bay.
The flight version of the lunar rover folded and tucked against the lunar landing module during fit tests on April 23, 1971. Image credit: NASA
The rover was designed to be strong but light: the flight version of the rover actually used on the moon weighed just 209 kilograms (460 pounds), capable of carrying a payload of an additional 490 kilograms (1,080 pounds) of astronauts, gear, and samples while in reduced lunar gravity. To stay light, the seats were nylon webbing over aluminum tubes, the seatbelts hooked together with velcro, and even the tires were metal mesh to reduce weight.
To balance strength and weight, the rover’s wheels were a spun aluminum hub with zinc-coated steel wire strands with titanium chevrons to provide grip. Image credit: NASA
The rover ran on a electric drive with a pair of non-rechargable 36-volt silver-zinc potassium hydroxide batteries kept stable with passive thermal controls. The batteries powered drive and steering motors, and provided juice for a 36 volt utility outlet mounted on the front of the rover. The four 0.25 horsepower drives motor ran at 10,000 rotations per minute, hooked into the wheels at an 80:1 ratio. The rover had two steering motors, each with 0.1 horsepower capacity. The two sets of wheels could work together or decouple completely. The primary use for the front outlet was to run either the communications relay or a TV camera.
Jim Irwin and Dave Scott suited up and on the flight rover for final fit-checks before stowing the payload in the lunar landing module. Image credit: NASA
The rover’s controller was a T-shaped hand controller directly between the two seats. It worked like a joystick: pushing forward for go, left or right to turn, and pulling back to activate the mechanical brakes. Although technically the rover could be driven by either astronaut, Commander Scott was the primary chauffeur.
Dave Scott practicing rover deployment with Boeing staff; artist’s concept of rover deployment. Image credits: NASA/NASA
The rover was deployed by the astronauts on the moon using a system of pulleys and braked reels with a mix of rope and cloth tape. The first astronaut climbed out to release the rover while the second slowly tilted it to the ground. They then unfolded the components, deploying the wheels and locking the frame open before completely releasing the rover to the surface. From there, Irwin and Scott clambered over their vehicle to lock the seatbacks in place, unfold footrests, and set cables, pins, and tripods for various equipment.
Scott adjusts a seatbelt while Irwin raises a seatback during practice deployment of the rover on May 14, 1971. Image credit: NASA
Astronauts Scott and Irwin always wore EVA gloves while handling the real lunar rover even during tests and inspections on the ground. This gave them actual-use experience right from the beginning, as they wouldn’t be able to pull off a glove for a fine-dexterity adjustment once on the moon.
Astronauts Bob Parker, Dave Scott, and Jim Irwin examine the real flight version of the lunar rover. Notice the mission astronauts (yellow arm bands) are wearing full EVA gloves. Image credit: NASA
As the first drivers on the moon, the pair covered 27.8 kilometers in 3 hours, 2 minutes of driving time spread over three different traverses. Each day was a single traverse, straying at most 5.0 kilometer from the landing module. The longest single traverse covered 12.5 kilometers. They navigated based on using a directional gyro and odometer to provide continual recordings of direction and distance, feeding that data into a computer to keep track of the traverse. For a manual backup, they had a lunar sundial.
Irwin and Scott catch a far less glamorous ride at the end of an outdoor EVA training session at Kennedy Space Center on May 11, 1971. Image credit: NASA
As for those colour-coded corvettes? In a 2005 email to NASA’s historians, Scott explained that he saw the thematic corvettes as a way to let the groundcrew working on the spacecraft know the astronauts were around and paying attention. Because the cars were so distinctive, even if the trio were just popping by to check on Saturn V and payload assembly or to say hello, people anywhere in the launch complex could look outside and recognize that the astronauts were on-site. It served as an unofficial extension of the Snoopy safety pins, making the need for safety in the human spaceflight program a little more personal.
The Apollo 15 astronauts also paid tribute to when safety precautions weren’t enough: they secretly installed the Fallen Astronaut during the final day on the moon. The highly stylized statue and plaque commemorate all the astronauts and cosmonauts who had died in the pursuit of space exploration.
Read more about the lunar rover specs here, and browse more archival photographs and maps from Apollo 15 here.
Top image: Apollo 15 astronauts Jim Irwin, Al Worden, and Dave Scott pose with their corvettes next to the 1-g lunar rover trainer as part of the June 11, 1971 special edition of Life Magazine. Credit: NASA/Ed Heneveld