On July 20, 1969, during the Apollo 11 mission, Neil Armstrong and Edwin Aldrin became the first human beings to land on the Moon. Excluding the Apollo 13 mission, others (12 to 17th mission) were successful moon landings. The distinguishing feature of the last three missions (15, 16, and 17) was the use of moon rovers or lunar rovers. Prior to that, astronauts could barely walk small distances, carrying the space suit and other equipment. This restricted the scope of lunar exploration, which led to the idea of developing a vehicle to traverse the lunar surface.
Moon Rover - History
Lunar rovers are electric vehicles used by astronauts to travel on the lunar surface. Till date, three such vehicles have been used on the Moon. The first lunar rover was used by astronauts David Scott and Jim Irwin of the Apollo 15 mission. The second rover was used during the Apollo 16 mission, by John Young and Charles Duke; and the third one was operated by Gene Cernan and Harrison Schmitt of the Apollo 17 mission.
The contract to manufacture the first Moon rover was given to Boeing. The first lunar roving vehicle was delivered 17 months from the date of contract, for a cost of 38,000,000 dollars. A total of four rovers were constructed - three of them for three lunar missions (15, 16, and 17), and one was kept aside for spare parts, after the cancellation of future Apollo missions.
Salient Features of the First Moon Rover
The first lunar rover was 10 feet 2 inches long, weighed 462 pounds, and was designed with an additional carrying capacity of 1080 pounds. When fully loaded, the ground clearance of the vehicle was 14 inches. The maximum height of the vehicle was 3.75 feet and its wheelbase measured approximately 7.5 feet. The frame of the vehicle was made of aluminum alloy 2219 tubing welded assemblies. The chassis consisted of three parts, which could be attached in the center. This feature facilitated folding of the vehicle to a small package, which helped in its transportation from the Earth to the Moon. This small package fitted into quadrant number 1 of the lunar module.
After reaching the lunar surface, the astronauts would start deployment of the vehicle, with the help of a system of pulleys and braked reels, using ropes and cloth tapes. The rover, which was stored in the lunar module with the underside of the chassis facing out, would be released and tilted slowly to the ground, using reels and tapes. Almost every process after this would be automatic. Once the rover was ready, other equipment like cameras, etc., were attached.
The rover had two adjacent foldable seats with adjustable footrests and seat belts. It carried a dish antenna on the mast of the front portion. The vehicle was fitted with two 36-volt batteries, which provided it with power. Separate steering systems were used for the front and rear wheels. On failure of any system, the other one could operate the Moon rover. The vehicle carried with it, a camera capable of sending color images of the Moon to the Earth via satellite.
Even though, the vehicle had the capacity to operate for 78 hours during the lunar day, limitations like capacity of life support systems of the astronauts, restricted it to a radius of six miles from the lunar module. The vehicle was controlled by a hand controller fitted in between the seats. Display modules fitted in front of the controller helped the astronauts with information about speed and temperature.
While in operation, devices in the vehicle continuously recorded the directions. This data was then fed to a computer, which in turn calculated the distance of the vehicle from the lunar module. These vehicles were built to operate in harsh weather conditions, and survived temperatures ranging from minus 200 to more than 200 degrees Fahrenheit.
These rovers proved to be a boon for the astronauts, as it helped them travel and cover large distances on the lunar surface; thus paving way for major scientific discoveries about the Moon. All three rovers used during the Apollo missions - 15, 16, and 17 were abandoned on the Moon itself, and are now in the list of artificial objects on the Moon.
Moon Rovers - Latest Developments
The rovers used during Apollo missions were aimed at increasing the area that could be explored by astronauts during their short stay on the Moon. Now, NASA is planning longer stays on the Moon, which will require more efficient vehicles. Hence, it has designed a prototype lunar truck, which can carry four astronauts, other equipment, and cargo.
NASA has also designed a small pressurized rover, to overcome the burden of space suits while traveling on the Moon. It is a pressurized habitat module mounted on the lunar truck chassis. The module can work as a cockpit for astronauts during space exploration, and can also function as a field station. Earlier, time span of the lunar exploration was dependent on the length of life support provided by the space suit. Traveling in a small pressurized rover will ensure that there is no burden of space suits, enabling the astronauts to cover greater distances, and also remain protected from unexpected solar events.
With many added advantages, this new hi-tech moon rover is sure to revolutionize the concept of the lunar roving vehicle!