On on July 20, 1969, history was made when astronauts aboard lunar module Eagle became the first people to land on the moon. Six hours later, mankind took its first lunar steps.
But decades prior to that monumental moment, researchers at the United States space agency NASA were already looking ahead and toward the creation of a space vehicle that would be up to the task of enabling astronauts to explore what many assumed would be a vast and challenging landscape. Initial studies for a lunar vehicle had been well underway since the 1950's and in a 1964 article published in Popular Science, NASA's Marshall Space Flight Center director Wernher von Braun gave preliminary details on how such a vehicle might work.
In the article, von Braun predicted that “even before the first astronauts set foot on the moon, a small, fully automatic roving vehicle may have explored the immediate vicinity of the landing site of its unmanned carrier spacecraft” and that the vehicle would be “remotely controlled by an armchair driver back on earth, who sees the lunar landscape roll past on a television screen as though he were looking through a car's windshield.”
Perhaps not so coincidentally, that was also the year that scientists at the Marshall center started work on the first concept for a vehicle. MOLAB, which stands for Mobile Laboratory, was a two-man, three-ton, closed-cabin vehicle with a range of 100 kilometers. Another idea being considered at the time was the Local Scientific Surface Module (LSSM), which initially was comprised of a shelter-laboratory (SHELAB) station and a small lunar-traversing vehicle (LTV) that could be driven or remotely controlled. They also looked at unmanned robotic rovers that could be controlled from Earth.
There were a number of important considerations the researchers had to keep in mind in designing a capable rover vehicle. One of the most important parts was the choice of wheels since very little was known about the moon's surface. The Marshall Space Flight Center's Space Sciences Laboratory (SSL) was tasked with determining the properties of lunar terrain and a test site was set up to examine a wide variety of wheel-surface conditions. Another important factor was weight as engineers had concerns that increasingly heavy vehicles would add to the costs of the Apollo/Saturn missions. They also wanted to ensure that the rover was safe and reliable.
To develop and test out various prototypes, the Marshall Center built a lunar surface simulator that mimicked the moon's environment with rocks and craters. While it was difficult to try and account for all the variables one may encounter, the researchers knew some things for certain. The lack of an atmosphere, an extreme surface temperature plus or minus 250 degrees Fahrenheit and very weak gravity meant that a lunar vehicle would have to be fully equipped with advanced systems and heavy-duty components.
In 1969, von Braun announced the establishment of a Lunar Roving Task Team at Marshall. The goal was to come up with a vehicle that would make it much easier to explore the moon on foot while wearing those bulky spacesuits and carrying limited supplies. In turn, this would allow for a greater range of movement once on the moon as the agency was preparing for the much anticipated return missions Apollo 15, 16 and 17. An aircraft manufacturer was awarded the contract to oversee the lunar rover project and deliver the final product. Thus testing would be carried out at a company facility in Kent, Washington, with the manufacturing taking place at the Boeing facility in Huntsville.
Here's a rundown of what went into the final design. It featured a mobility system (wheels, traction drive, suspension, steering and drive control) that could run over obstacles up to 12 inches high and 28-inch diameter craters. The tires featured a distinct traction pattern that prevented them from sinking into the soft lunar soil and were supported by springs to relieve most of its weight. This helped to simulate the moon's weak gravity. In addition, a thermal protection system that dissipated heat was included to helped to protect its equipment from temperature extremes on the moon.
The lunar rover's front and rear steering motors were controlled using a T-shaped hand controller positioned directly in the front of the two seats. There's also a control panel and display with switches for power, steering, drive power and drive enabled. The switches allowed the operators to select their source of power for these various functions. For communications, the rover came equipped with a television camera, a radio-communications system and telemetry - all of which can be used to send data and report observations to team members on Earth.
In March of 1971, Boeing delivered the first flight model to NASA, two weeks ahead of schedule. After it was inspected, the vehicle was sent to Kennedy Space Center for preparations for the lunar mission launch scheduled for late July. In all, four lunar rovers were built, one each for Apollo missions while the fourth was used for spare parts. The total cost was cost of $38 million.
The operation of the lunar rover during the Apollo 15 mission was a major reason the trip was deemed a huge success, though it wasn't without it's hiccups. For example, Astronaut Dave Scott quickly discovered on the first trip out that the front steering mechanism wasn't working but that the vehicle could still be driven without a hitch thanks to rear wheel steering. In any case, the crew was able to eventually fix the problem and complete their three planned trips to collect soil samples and take photos.
In all, the astronauts traveled 15 miles in the rover and covered almost four times as much lunar terrain as the those on the previous Apollo 11, 12 and 14 missions combined. Theoretically, the astronauts may have gone further but kept to a limited range to ensure that they remained within walking distance of the lunar module, just in case the rover broke down unexpectedly. Top speed was about 8 miles per hour and the maximum speed recorded was about 11 miles per hour.