The Lunar Roving Vehicle (LRV) was an electric vehicle designed to operate in the
low-gravity vacuum of the Moon and to be capable of traversing the lunar surface,
allowing the Apollo astronauts to extend the range of their surface extravehicular
activities. Three LRVs were driven on the Moon, one on Apollo 15 by astronauts
David Scott and Jim Irwin, one on Apollo 16 by John Young and Charles Duke, and
one on Apollo 17 by Gene Cernan and Harrison Schmitt. Each rover was used on three
traverses, one per day over the three day course of each mission. On Apollo 15
the LRV was driven a total of 27.8 km in 3 hours, 2 minutes of driving time. The
longest single traverse was 12.5 km and the maximum range from the LM was 5.0 km.
On Apollo 16 the vehicle traversed 26.7 km in 3 hours 26 minutes of driving. The
longest traverse was 11.6 km and the LRV reached a distance of 4.5 km from the LM.
On Apollo 17 the rover went 35.9 km in 4 hours 26 minutes total drive time. The
longest traverse was 20.1 km and the greatest range from the LM was 7.6 km.
The Lunar Roving Vehicle had a mass of 210 kg and was designed to hold a
payload of an additional 490 kg on the lunar surface. The frame was 3.1 meters
long with a wheelbase of 2.3 meters. The maximum height was 1.14 meters. The
frame was made of aluminum alloy 2219 tubing welded assemblies and consisted of
a 3 part chassis which was hinged in the center so it could be folded up and hung
in the Lunar Module quad 1 bay. It had two side-by-side foldable seats made of
tubular aluminum with nylon webbing and aluminum floor panels. An armrest was
mounted between the seats, and each seat had adjustable footrests and a velcro
seatbelt. A large mesh dish antenna was mounted on a mast on the front center of
the rover. The suspension consisted of a double horizontal wishbone with upper
and lower torsion bars and a damper unit between the chassis and upper wishbone.
Fully loaded the LRV had a ground clearance of 36 cm.
The wheels consisted of a spun aluminum hub and an 81.8 cm diameter, 23 cm wide tire made of zinc coated woven 0.083 cm diameter steel strands attached to the rim and discs of formed aluminum. Titanium chevrons covered 50% of the contact area to provide traction. Inside the tire was a 64.8 cm diameter bump stop frame to protect the hub. Dust guards were mounted above the wheels. Each wheel had its own electric drive, a DC series wound 0.25 hp motor capable of 10,000 rpm, attached to the wheel via an 80:1 harmonic drive, and a mechanical brake unit. Manuevering capability was provided through the use of front and rear steering motors. Each series wound DC steering motor