In 1972, Apollo 17 astronauts tore a rover fender on the Moon; they rebuilt it with four spare maps, duct tape, and clamps, and the fix lasted through 9.1 km of driving

During NASA's final mission to the Moon, Apollo 17, in December 1972, Commander Eugene Cernan ripped off the rear extension of the rover's fender, an event now remembered for an improvised repair that used only available materials. According to NASA's Apollo Lunar Surface Journal, while making final preparations to drive to the ALSEP deployment site during the first moonwalk, Cernan accidentally tore the rear extension of the rover's right rear fender after catching the geology hammer hidden in his spacesuit's calf pocket.

The crew and Mission Control created a new fender out of four extra lunar maps, clamps, and duct tape, which held until the end of the mission. Apollo 17 was launched on December 7, 1972, with Cernan and Harrison Schmitt, the lunar module pilot, landing in the Taurus-Littrow valley while Ronald Evans, the command module pilot, remained in lunar orbit. This was the sixth and last Apollo Moon landing, with Cernan and Schmitt using the lunar rover for three different excursions on the lunar surface. The lunar rover had already been used on Apollo 15 and Apollo 16.

Why a torn fender was more than a cosmetic problem


Losing the fender was a serious problem for the Moon rover. Lunar soil, or regolith, is fine and sharp because it has not been weathered by wind and rain like soil on Earth. Without the fender, the rover's wheels sent dust from the lunar soil all over the astronauts and their spacesuits, as well as the rover equipment itself, during driving. This mattered because the crew still had two more EVA missions scheduled, and the rover had to keep functioning. At first, Cernan tried a quick fix with duct tape. At the end of the first EVA mission during the return trip to the module, the tape tore and the whole fender extension detached from the rover. The astronauts left it in place, giving Mission Control only a few hours to find a permanent fix.

The fix: Four spare lunar maps, tape, and clamps

During the break after the first lunar walk, support personnel at the Mission Control Center in Houston designed a makeshift replacement fender using materials they knew were available on board. The next morning, Cernan and Schmitt assembled four unused laminated maps of the Moon to create a sturdy base in place of the fender portion lost during the previous excursion, following the procedure radioed up from Houston. They attached this makeshift solution to the rover chassis using clamps removed from the optical telescope mount in the lunar module. There was no way to test the fix on Earth, and no spare fender parts were available. Maps and telescope clamps were not originally intended for such purposes, but they were the closest thing to the required rigidity. The physical assembly itself was done entirely with materials already inside the lunar module cabin.

How long the paper fender actually held up

According to NASA's Apollo Lunar Surface Journal, the new fender was fitted onto the rover before the start of the second moonwalk. It had to handle actual driving, not just stay in place when the vehicle was not moving. By the time the team reached Station 2, the journal notes, the new part had already been tested for 9.1 kilometers of driving, a checkpoint reached partway through a total run that would eventually reach 29 kilometers before it started to break down near the end of the third and last moonwalk. NASA records say the breakdown happened because of sun exposure and because dust and small rocks hit the bottom of the fender.

Where the fender ended up

Before leaving the Moon, Cernan took off the fender that had been fixed. Unlike heavier equipment left behind on the lunar surface to save weight, this lightweight assembly of maps and tape came back to Earth with the other mission equipment. Later, NASA's Johnson Space Center sent it to the Smithsonian. Now the object, which is four maps stuck together with grey adhesive tape, is in the collection at the Smithsonian's National Air and Space Museum. The museum lists it as a fender extension made during the Apollo 17 mission.

Why this repair still gets brought up

It reminds us that a broken piece, fixed with maps and tools not meant for the job inside a small space capsule, kept NASA's last mission to the Moon going without major problems. The astronauts and Mission Control had to improvise with the materials already on hand, and the fix lasted long enough to matter; more than five decades later, it's still on display as a reminder of that improvisation.