On this day in aviation history: In 1971 astronauts go for a drive. Apollo 15 was the first of the Apollo missions capable of longer times on the moon’s surface and greater surface mobility. Exploration and geological investigations at the Hadley-Apennine landing site were enhanced by the addition of the Lunar Roving Vehicle (LRV). Built by Boeing, the LRV carried two astronauts, their tools, scientific equipment, communications gear, and lunar samples. It was the first manned surface transportation system designed to operate on the Moon’s surface and marked the beginning of a new technology and was an experiment to overcome many new and challenging problems in lunar vehicle design and operations. The lack of an atmosphere on the Moon, the extreme surface temperature, the weak gravity, and other unknowns associated with the lunar soil and topography imposed design requirements on the LRV which had no comparison in Earth vehicles and for which designers had no experience. The LRV was ten feet, two inches long, was 44.8 inches high, and had a 7.5-foot wheelbase. Each wheel was individually powered by a quarter-horsepower electric motor and the vehicles top speed was about eight miles per hour on a relatively smooth surface. Wire-mesh tires were specially designed to improve traction because the LRVs decreased lunar weight meant less frictional pressure could be exerted on the dusty lunar surface. The actual tire structure was formed from fine zinc-coated woven steel strands attached to a spun aluminum wheel hub. These gave the LRV 12 inches of ground clearance. Two 36-volt batteries provided the vehicles power, although either battery could power all vehicle systems if required. The front and rear wheels had separate steering systems, but if one steering system failed the vehicle could be operated with the other system. Weighing approximately 460 pounds on Earth, when deployed on the Moon the LRV carried a total payload weight of about 1,080 pounds, more than twice its own weight. Cargo included two astronauts and their portable life support systems (about 800 pounds), 100 pounds of communications equipment, 120 pounds of scientific equipment and photographic gear, and 60 pounds of lunar samples. The LRV was designed to operate for 78 hours during the lunar day. It could make several exploration sorties up to a cumulative distance of 40 miles. Because of limitations in the astronauts portable life support system, the vehicles range was restricted to a radius of about six miles from the lunar module in case astronauts had to walk back from an immobilized LRV. The three rovers used on Apollo missions 15, 16, and 17 were abandoned on the surface of the moon. The rover used on Apollo 17 was left on the lunar surface at Taurus-Littrow and was seen by the Lunar Reconnaissance Orbiter during passes above the lunar surface made in 2009 and 2011.
Posted on: Wed, 30 Jul 2014 16:32:17 +0000
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