Lunar rover
Encyclopedia
The Lunar Roving Vehicle (LRV) or lunar rover
Lunar rover
The Lunar Roving Vehicle or lunar rover was a battery-powered four-wheeled rover used on the Moon in the last three missions of the American Apollo program during 1971 and 1972...

was a battery-powered four-wheeled rover
Rover (space exploration)
A rover is a space exploration vehicle designed to move across the surface of a planet or other astronomical body. Some rovers have been designed to transport members of a human spaceflight crew; others have been partially or fully autonomous robots...

 used on the Moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 in the last three missions of the American Apollo program (15, 16, and 17) during 1971 and 1972. It was popularly known as the moon buggy, a play on the phrase "dune buggy
Dune buggy
A dune buggy is a recreational vehicle with large wheels, and wide tires, designed for use on sand dunes or beaches. The design is usually a modified vehicle and engine mounted on an open chassis. The modifications usually attempt to increase the power-to-weight ratio by either lightening the...

".

The LRV was transported to the Moon on the Apollo Lunar Module
Apollo Lunar Module
The Apollo Lunar Module was the lander portion of the Apollo spacecraft built for the US Apollo program by Grumman to carry a crew of two from lunar orbit to the surface and back...

 (LM) and, once unpacked on the surface, could carry one or two astronauts, their equipment, and lunar samples.

History

The concept of a lunar rover predated Apollo, with a 1952–1954 series in Collier's Weekly
Collier's Weekly
Collier's Weekly was an American magazine founded by Peter Fenelon Collier and published from 1888 to 1957. With the passage of decades, the title was shortened to Collier's....

magazine by Wernher von Braun
Wernher von Braun
Wernher Magnus Maximilian, Freiherr von Braun was a German rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and in the United States after that.A former member of the Nazi party,...

 and others, "Man Will Conquer Space Soon!
Man Will Conquer Space Soon!
Man Will Conquer Space Soon! was the title of a famous series of 1950s magazine articles in Collier's detailing Wernher von Braun's plans for manned spaceflight. Edited by Cornelius Ryan, the individual articles were authored by such space notables of the time as Willy Ley, Fred Lawrence Whipple,...

" In this, von Braun, who had come to America from Germany under Operation Paperclip
Operation Paperclip
Operation Paperclip was the Office of Strategic Services program used to recruit the scientists of Nazi Germany for employment by the United States in the aftermath of World War II...

 and was a leader at the Army Ballistic Missile Agency
Army Ballistic Missile Agency
The Army Ballistic Missile Agency was the agency formed to develop the US Army's first intermediate range ballistic missile. It was established at Redstone Arsenal on February 1, 1956 and commanded by Major General John B...

, described a six-week stay on the Moon, featuring 10-ton tractor trailers for moving supplies.

In 1956, Mieczyslaw G. Bekker
Mieczyslaw G. Bekker
Mieczysław Gregory Bekker was a Polish engineer and scientist.Bekker was born in Strzyżów, near Hrubieszow, Poland and graduated from Warsaw Technical University in 1929.-Early Career:...

, a native of Poland
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

 and then a professor at the University of Michigan
University of Michigan
The University of Michigan is a public research university located in Ann Arbor, Michigan in the United States. It is the state's oldest university and the flagship campus of the University of Michigan...

 and a consultant to the Land Locomotion Laboratory at the U.S. Army Tank-Automotive Command, published two books on land locomotion. These books provided much of the theoretical base for future lunar vehicle development.

Early lunar mobility studies

In the February 1964 issue of Popular Science
Popular Science
Popular Science is an American monthly magazine founded in 1872 carrying articles for the general reader on science and technology subjects. Popular Science has won over 58 awards, including the ASME awards for its journalistic excellence in both 2003 and 2004...

, von Braun, then director of NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

's Marshall Space Flight Center
Marshall Space Flight Center
The George C. Marshall Space Flight Center is the U.S. government's civilian rocketry and spacecraft propulsion research center. The largest center of NASA, MSFC's first mission was developing the Saturn launch vehicles for the Apollo moon program...

 (MSFC), discussed the need for a lunar surface vehicle, and revealed that studies had been underway at MSFC in conjunction with Lockheed, Bendix, Boeing, General Motors, Brown Engineering, Grumman, and Bell Aerospace.

Beginning in the early 1960s, a series of studies centering on lunar mobility were conducted under MSFC. This began with the Lunar Logistics System (LLS), followed by the Mobility Laboratory (MOLAB), then the Lunar Scientific Survey Module (LSSM), and finally the Mobility Test Article (MTA). In early planning for the Apollo Program, it had been assumed that two Saturn V
Saturn V
The Saturn V was an American human-rated expendable rocket used by NASA's Apollo and Skylab programs from 1967 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload...

 launch vehicles would be used for each lunar mission: one for sending the crew aboard a Lunar Surface Module (LSM) to lunar orbit, landing, and returning, and a second for sending an LSM-Truck (LSM-T) with all of the equipment, supplies, and transport vehicle for use by the crew while on the surface. All of the first MSFC studies were based on this dual-launch assumption, allowing a large, heavy, roving vehicle.

The LLS studies were begun by Grumman and Northrop in the fall of 1962; these were designs for pressurized cabin vehicles with electric motors for each wheel. At about this same time, Bendix and Boeing were conducting internal studies on lunar transportation systems. Bekker, now with General Motors Defense Research Laboratories (GMDRL) at Santa Barbara, California
Santa Barbara, California
Santa Barbara is the county seat of Santa Barbara County, California, United States. Situated on an east-west trending section of coastline, the longest such section on the West Coast of the United States, the city lies between the steeply-rising Santa Ynez Mountains and the Pacific Ocean...

, was completing a study for NASA's Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...

 on a small, unmanned lunar roving vehicle for the Surveyor Program
Surveyor program
The Surveyor Program was a NASA program that, from 1966 through 1968, sent seven robotic spacecraft to the surface of the Moon. Its primary goal was to demonstrate the feasibility of soft landings on the Moon...

. Ferenc Pavlics
Ferenc Pavlics
Ferenc Pavlics , mechanical engineer, developer for NASA Apollo Lunar rover.-Childhood and early life:Ferenc Pavlics was born in Balozsameggyes on February 3, 1928. His father, Károly Pavlics and mother, Rosina Perusich were both teachers teaching in the elementary school of Balozsameggyes...

, originally from Hungary
Hungary
Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...

, used a wire-mesh design for "resilient wheels," a design that would be followed in future small rovers.

In early 1963, NASA selected MSFC for studies in an Apollo Logistics Support System (ALSS). Following reviews of all earlier efforts, this resulted in a 10-volume report. Included was the need for a pressurized vehicle in the 6490–8470 lb (2,943.8–3,841.9 kg) weight range, accommodating two men with their expendables and instruments for traverses up to two weeks in duration. This was called a Mobility Laboratory (MOLAB). In June 1964, MSFC awarded contracts for MOLAB studies and Mobility Test Articles (MTAs) to Bendix and to Boeing, with GMDRL as vehicle technology subcontractor. Bell Aerospace was already under contract for studies of Lunar Flying Vehicles.

Even as ALSS was underway, MSFC was examining a less ambitious surface exploration activity, the Local Scientific Surface Module (LSSM). This would be composed of a fixed, habitable shelter-laboratory (SHELAB) with a small lunar-traversing vehicle (LTV) that could either carry one man or be remotely controlled. LSSM would be carried on an LSM-T, thus still requiring a dual launch. The Propulsion and Vehicle Engineering (P&VE) support contractor Hayes International made a preliminary study of the shelter and vehicle. Also, for the potential need of a MOLAB-like vehicle in future, enlarged lunar explorations, the MOLAB efforts were continued for some time, resulting in several full-scale MTAs.

With pressure from Congress to hold down Apollo costs, Saturn V production was reduced, allowing only a single booster per mission. It would then be necessary for any roving vehicle to be carried on the same Lunar Module as transporting the astronauts. In November 1964, ALSS was put on indefinite hold, but Bendix and Boeing were given study contracts for small rovers under the LSSM program. The name of the Lunar Excursion Module was changed to simply the Lunar Module
Apollo Lunar Module
The Apollo Lunar Module was the lander portion of the Apollo spacecraft built for the US Apollo program by Grumman to carry a crew of two from lunar orbit to the surface and back...

, indicating that the capability for powered "excursions" away from a lunar-lander base did not yet exist. There could be no SHELAB — the astronauts would work out of the LM — and the LTV accommodating two persons took the name Local Scientific Surface Module (LSSM). MSFC was also examining unmanned robotic rovers that could be controlled from the Earth.

From the start of MSFC, Huntsville, Alabama
Huntsville, Alabama
Huntsville is a city located primarily in Madison County in the central part of the far northern region of the U.S. state of Alabama. Huntsville is the county seat of Madison County. The city extends west into neighboring Limestone County. Huntsville's population was 180,105 as of the 2010 Census....

-based Brown Engineering Company (BECO) had participated in all of its lunar mobility efforts. In 1965, BECO became the prime support contractor for MSFC's P&VE Laboratory. With an urgent need to determine the feasibility of a two-man LSSM, von Braun bypassed the usual procurement process and had P&VE's Advanced Studies Office directly task BECO to design, build, and test a MTA for the vehicle. While Bendix and Boeing would continue with work leading to LSSV\M concepts and designs, the MTA was vital for MSFC human factors studies involving spacesuit-clad astronauts interfacing with power, telemetry, navigation, and life-support equipment on the rover. Eduardo San Juan, an immigrant from the Philippines who had led the earlier study by Hayes International, joined BECO to lead the LSSM MTA development.

In designing the LSSM MTA, full use was made of all earlier small-rover studies, and commercially available components were incorporated wherever possible. The selection of wheels was of great importance, and almost nothing was known at that time about the lunar surface. The MSFC Space Sciences Laboratory (SSL) was responsible for predicting surface properties. BECO was also the prime support contractor for the SSL and set up a test area to examine a wide variety of wheel-surface conditions. To simulate Pavlics' "resilient wheel," a four-foot-diameter inner tube wrapped with nylon ski rope was used. On the MTA, each wheel had a small electric motor, with overall power provided by standard truck batteries. A roll bar gave protection from overturn accidents.

In early 1966, BECO's MTA became available for examining human factors and other testing. MSFC built a small test track with craters and rock debris where the LSSM and MOLAB MTAs were compared; it was soon obvious that a small rover would be best for the proposed missions. The vehicle was also operated in remote mode to determine characteristics in tests that might be dangerous to the operator, such as acceleration, bounce-height, and turn-over tendency as it traveled at higher speeds and over simulated obstacles. The LSSM performance under one-sixth gravity was obtained through flights on a KC-135A aircraft in a Reduced Gravity
Vomit Comet
A Reduced Gravity Aircraft is a type of fixed-wing aircraft that briefly provides a nearly weightless environment in which to train astronauts, conduct research and film motion pictures....

 parabolic maneuver; among other things, the need for a very soft wheel and suspension combination was shown. Although Pavlics' wire-mesh wheels were not available for the MTA, testing of these was conducted on various soils at the Waterways Experiment Station
Waterways Experiment Station
The Engineer Research and Development Center ' is a US Army Corps of Engineers laboratory organization whose mission is to "Provide science, technology, and expertise in engineering and environmental sciences in support of our Armed Forces and the Nation to make the world safer and better." The...

 of the U.S. Army Corps of Engineers
United States Army Corps of Engineers
The United States Army Corps of Engineers is a federal agency and a major Army command made up of some 38,000 civilian and military personnel, making it the world's largest public engineering, design and construction management agency...

 at Vicksburg, Mississippi
Vicksburg, Mississippi
Vicksburg is a city in Warren County, Mississippi, United States. It is the only city in Warren County. It is located northwest of New Orleans on the Mississippi and Yazoo rivers, and due west of Jackson, the state capital. In 1900, 14,834 people lived in Vicksburg; in 1910, 20,814; in 1920,...

. Later, when wire-mesh wheels were tested on low-g flights, the need for wheel fenders to reduce dust contamination was found. The LSSM MTA was extensively tested at the U.S. Army's Yuma Proving Ground in Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

, as well as the Army's Aberdeen Proving Ground
Aberdeen Proving Ground
Aberdeen Proving Ground is a United States Army facility located near Aberdeen, Maryland, . Part of the facility is a census-designated place , which had a population of 3,116 at the 2000 census.- History :...

 in Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...

.

Apollo Lunar Roving Vehicle

During 1965 and 1967, the Summer Conference on Lunar Exploration and Science brought together leading scientists to assess NASA's planning for exploring the Moon and to make recommendations. One of their findings was that the LSSM was critical to a successful program and should be given major attention. At MSFC, von Braun established the Lunar Roving Task team, and in May 1969, NASA selected the Lunar Roving Vehicle (LRV) for use in manned lunar missions and approved the Manned Lunar Rover Vehicle Program as a MSFC hardware development. Saverio F. "Sonny" Morea was named the LRV program manager.

On 11 July 1969, just after the successful Moon landing of Apollo 11
Apollo 11
In early 1969, Bill Anders accepted a job with the National Space Council effective in August 1969 and announced his retirement as an astronaut. At that point Ken Mattingly was moved from the support crew into parallel training with Anders as backup Command Module Pilot in case Apollo 11 was...

, a request for proposal
Request for Proposal
A request for proposal is issued at an early stage in a procurement process, where an invitation is presented for suppliers, often through a bidding process, to submit a proposal on a specific commodity or service. The RFP process brings structure to the procurement decision and is meant to...

 for the final development and building the Apollo LRV was released by MSFC. Boeing, Bendix, Grumman, and Chrysler submitted proposals. Following three months of proposal evaluation and negotiations, Boeing was selected as the Apollo LRV prime contractor on 28 October 1969. Boeing would manage the LRV project under Henry Kudish in Huntsville, Alabama
Huntsville, Alabama
Huntsville is a city located primarily in Madison County in the central part of the far northern region of the U.S. state of Alabama. Huntsville is the county seat of Madison County. The city extends west into neighboring Limestone County. Huntsville's population was 180,105 as of the 2010 Census....

. As a major subcontractor, General Motors' Defense Research Laboratories in Santa Barbara, California
Santa Barbara, California
Santa Barbara is the county seat of Santa Barbara County, California, United States. Situated on an east-west trending section of coastline, the longest such section on the West Coast of the United States, the city lies between the steeply-rising Santa Ynez Mountains and the Pacific Ocean...

, would furnish the mobility system (wheels, motors, and suspension); this effort would be led by Ferenc Pavlics. Boeing in Seattle, Washington
Seattle, Washington
Seattle is the county seat of King County, Washington. With 608,660 residents as of the 2010 Census, Seattle is the largest city in the Northwestern United States. The Seattle metropolitan area of about 3.4 million inhabitants is the 15th largest metropolitan area in the country...

, would furnish the electronics and navigation system. Vehicle testing would take place at the Boeing facility in Kent, Washington
Kent, Washington
Kent is a city located in King County, Washington, United States, and is the third largest city in King County and the sixth largest in the state. An outlying suburb of Seattle, Kent is also the corporate home for companies such as REI and Oberto Sausage...

, and the chassis manufacturing and overall assembly would be at the Boeing facility in Huntsville.

The first cost-plus-incentive-fee contract to Boeing was for $19,000,000 and called for delivery of the first LRV by 1 April 1971. Cost overruns, however, led to a final cost of $38,000,000, which was about the same as NASA's original estimate. Four lunar rovers were built, one each for Apollo missions 15, 16, and 17; and one used for spare parts after the cancellation of further Apollo missions. Other LRV models were built: a static model to assist with human factors
Human factors
Human factors science or human factors technologies is a multidisciplinary field incorporating contributions from psychology, engineering, industrial design, statistics, operations research and anthropometry...

 design; an engineering model to design and integrate the subsystems; two one-sixth gravity models for testing the deployment mechanism; a one-gravity trainer to give the astronauts instruction in the operation of the rover and allow them to practice driving it; a mass model to test the effect of the rover on the LM structure, balance, and handling; a vibration test unit to study the LRV's durability and handling of launch stresses; and a qualification test unit to study integration of all LRV subsystems. A paper by Savero Morea gives details of the LRV system and its development.
LRVs were used for greater surface mobility during the Apollo J-class missions, Apollo 15
Apollo 15
Apollo 15 was the ninth manned mission in the American Apollo space program, the fourth to land on the Moon and the eighth successful manned mission. It was the first of what were termed "J missions", long duration stays on the Moon with a greater focus on science than had been possible on previous...

, Apollo 16
Apollo 16
Young and Duke served as the backup crew for Apollo 13; Mattingly was slated to be the Apollo 13 command module pilot until being pulled from the mission due to his exposure to rubella through Duke.-Backup crew:...

, and Apollo 17
Apollo 17
Apollo 17 was the eleventh and final manned mission in the American Apollo space program. Launched at 12:33 a.m. EST on December 7, 1972, with a three-member crew consisting of Commander Eugene Cernan, Command Module Pilot Ronald Evans, and Lunar Module Pilot Harrison Schmitt, Apollo 17 remains the...

. The rover was first used on 31 July 1971, during the Apollo 15 mission. This greatly expanded the range of the lunar explorers. Previous teams of astronauts were restricted to short walking distances around the landing site due to the bulky space suit equipment required to sustain life in the lunar environment. The range, however, was operationally restricted to remain within walking distance of the lunar module, in case the rover broke down at any point. The rovers were designed with a top speed of about 8 mph (13 km/h), although Eugene Cernan recorded a maximum speed of 11.2 mph (18 km/h), giving him the (unofficial) lunar land-speed record.

The LRV was developed in only 17 months and yet performed all its functions on the Moon with no major anomalies. Scientist-astronaut Harrison Schmitt
Harrison Schmitt
Harrison Hagan "Jack" Schmitt is an American geologist, a retired NASA astronaut, university professor, and a former U.S. senator from New Mexico....

 of Apollo 17 said, "The Lunar Rover proved to be the reliable, safe and flexible lunar exploration vehicle we expected it to be. Without it, the major scientific discoveries of Apollo 15, 16, and 17 would not have been possible; and our current understanding of lunar evolution would not have been possible."

The LRVs did experience some minor problems. The rear fender
Fender (vehicle)
Fender is the US English term for the part of an automobile, motorcycle or other vehicle body that frames a wheel well . Its primary purpose is to prevent sand, mud, rocks, liquids, and other road spray from being thrown into the air by the rotating tire. Fenders are typically rigid and can be...

 extension on the Apollo 16 LRV was lost during the mission's second extra-vehicular activity
Extra-vehicular activity
Extra-vehicular activity is work done by an astronaut away from the Earth, and outside of a spacecraft. The term most commonly applies to an EVA made outside a craft orbiting Earth , but also applies to an EVA made on the surface of the Moon...

 (EVA) at station 8 when John Young bumped into it while going to assist Charles Duke. The dust thrown up from the wheel covered the crew, the console, and the communications equipment. High battery temperatures and resulting high power consumption ensued. No repair attempt was mentioned.

The fender extension on the Apollo 17 LRV broke when accidentally bumped by Eugene Cernan with a hammer handle. Cernan and Schmitt taped the extension back in place, but due to the dusty surfaces, the tape did not adhere and the extension was lost after about one hour of driving, causing the astronauts to be covered with dust. For their second EVA, a replacement "fender" was made with some EVA maps, duct tape, and a pair of clamps from inside the Lunar Module that were nominally intended for the moveable overhead light. This repair was later undone so that the clamps could be taken inside for the return launch. The maps were brought back to Earth and are now on display at the National Air and Space Museum
National Air and Space Museum
The National Air and Space Museum of the Smithsonian Institution holds the largest collection of historic aircraft and spacecraft in the world. It was established in 1976. Located in Washington, D.C., United States, it is a center for research into the history and science of aviation and...

. The abrasion from the dust is evident on some portions of the makeshift fender.
The color TV camera
Apollo TV camera
Television cameras used on the Apollo Project's missions varied in design, with image quality improving significantly with each design. A camera was carried in the Apollo Command Module...

 mounted on the front of the LRV could be remotely operated by Mission Control
Mission Control Center
A mission control center is an entity that manages aerospace vehicle flights, usually from the point of lift-off until the landing or the end of the mission. A staff of flight controllers and other support personnel monitor all aspects of the mission using telemetry, and send commands to the...

 in pan and tilt axes as well as zoom. This allowed far better television coverage of the EVA than the earlier missions. On each mission, at the conclusion of the astronauts' stay on the surface, the commander drove the LRV to a position away from the Lunar Module so that the camera could record the ascent stage launch. The camera operator in Mission Control experienced difficulty in timing the various delays so that the LM ascent stage was in frame through the launch. On the third and final attempt (Apollo 17), the launch and ascent were successfully tracked.

NASA's rovers, left behind, are among the artificial objects on the Moon, as are the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

's unmanned rovers, Lunokhod 1
Lunokhod 1
Lunokhod 1 was the first of two unmanned lunar rovers landed on the Moon by the Soviet Union as part of its Lunokhod program. The spacecraft which carried Lunokhod 1 was named Luna 17...

 and Lunokhod 2
Lunokhod 2
Lunokhod 2 was the second of two unmanned lunar rovers landed on the Moon by the Soviet Union as part of the Lunokhod program....

.

Features and specifications

The Apollo Lunar Roving Vehicle was an electric-powered vehicle
Battery electric vehicle
A battery electric vehicle, or BEV, is a type of electric vehicle that uses chemical energy stored in rechargeable battery packs. BEVs use electric motors and motor controllers instead of, or in addition to, internal combustion engines for propulsion.A battery-only electric vehicle or...

 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 used on the Moon, one on Apollo 15 by astronauts David Scott
David Scott
David Randolph Scott is an American engineer, test pilot, retired U.S. Air Force officer, and former NASA astronaut and engineer, who was one of the third group of astronauts selected by NASA in October 1963...

 and Jim Irwin
James Irwin
James Benson Irwin was an American astronaut and engineer. He served as Lunar Module pilot for Apollo 15, the fourth human lunar landing; he was the eighth person to walk on the Moon.-Early life:...

, one on Apollo 16 by John Young and Charles Duke, and one on Apollo 17 by Eugene Cernan and Harrison Schmitt
Harrison Schmitt
Harrison Hagan "Jack" Schmitt is an American geologist, a retired NASA astronaut, university professor, and a former U.S. senator from New Mexico....

. The mission commander served as the driver, occupying the left-hand seat of each LRV. Features are available in papers by Morea, Baker, and Kudish.

Mass and payload

The Lunar Roving Vehicle had a mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...

 of 463 lb (210 kg), which resulted in a lunar weight of 77.2 lbf (35 kgf) - and was designed to hold a payload of an additional 1080 lb (489.9 kg) on the lunar surface. The frame was 10 ft (3 m) long with a wheelbase of 7.5 ft (2.3 m). The height of the vehicle was 3.6 feet (1.1 m). The frame was made of aluminum alloy 2219 tubing welded assemblies and consisted of a three-part chassis that was hinged in the center so it could be folded up and hung in the Lunar Module Quadrant 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
Velcro
Velcro is the brand name of the first commercially marketed fabric hook-and-loop fastener, invented in 1948 by the Swiss electrical engineer George de Mestral...

 seat belt. 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
Torsion beam suspension
thumb|250px|A front [[VW Beetle]] suspension cross-sectionA torsion bar suspension, also known as a torsion spring suspension or torsion beam suspension, is a general term for any vehicle suspension that uses a torsion bar as its main weight bearing spring...

 and a damper unit between the chassis and upper wishbone. Fully loaded, the LRV had a ground clearance of 14 inches (35.6 cm).

Wheels and power

The wheels were manufactured by General Motors Defense Research Laboratories. Ferenc Paulics was given special recognition by NASA for developing the "resilient wheel. They consisted of a spun aluminum hub and a 32 inches (81.3 cm) diameter, 9 inches (22.9 cm) wide tire made of zinc-coated woven 0.033 inch (0.8382 mm) diameter steel strands attached to the rim and discs of formed aluminum. Titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 chevrons covered 50 percent of the contact area to provide traction. Inside the tire was a 25.5 inches (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 made by Delco, DC series-wound motor capable of 0.25 hp at 10,000 rpm, attached to the wheel via an 80:1 harmonic drive
Harmonic Drive
A Harmonic Drive is a special type of mechanical gear system that can improve certain characteristics compared to traditional gearing systems . It was invented in 1957 and is now produced by Harmonic Drive LLC...

, and a mechanical brake unit.

Maneuvering capability was provided through the use of front and rear steering motors. Each series-wound DC
Direct current
Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...

 steering motor was capable of 0.1 hp. Both sets of wheels would turn in opposite directions, giving a steering radius of 10 feet (3 m), or could be decoupled so only one set would be used for steering. They could also free-wheel in case of drive failure.

Power was provided by two 36-volt silver-zinc potassium hydroxide non-rechargeable batteries
Primary cell
A primary cell is any kind of battery in which the electrochemical reaction is not reversible, rendering the cell non-rechargeable. A common example of a primary cell is the disposable battery. Unlike a secondary cell, the reaction cannot be reversed by running a current into the cell; the chemical...

 with a capacity of 121 A·h each (a total of 242 A·h), translating into a range of 57 miles (91.7 km). These were used to power the drive and steering motors and also a 36-volt utility outlet mounted on front of the LRV to power the communications relay unit or the TV camera. LRV batteries and electronics were passively cooled, using change-of-phase wax thermal capacitor
Capacitor
A capacitor is a passive two-terminal electrical component used to store energy in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors separated by a dielectric ; for example, one common construction consists of metal foils separated...

 packages and reflective, upward-facing radiating surfaces. While driving, radiators were covered with mylar blankets to minimize dust accumulation. When stopped, the astronauts would open the blankets, and manually remove excess dust from the cooling surfaces with hand brushes.

Control and navigation

A T-shaped hand controller situated between the two seats controlled the four drive motors, two steering motors, and brakes. Moving the stick forward powered the LRV forward, left and right turned the vehicle left or right, and pulling backwards activated the brakes. Activating a switch on the handle before pulling back would put the LRV into reverse. Pulling the handle all the way back activated a parking brake. The control and display modules were situated in front of the handle and gave information on the speed, heading, pitch, and power and temperature levels.

Navigation was based on continuously recording direction and distance through use of a directional gyro
Heading indicator
The heading indicator is a flight instrument used in an aircraft to inform the pilot of the aircraft's heading. It is sometimes referred to by its older names, the directional gyro or DG, and also direction indicator or DI.- Use :The primary means of establishing the heading in most small...

 and odometer
Odometer
An odometer or odograph is an instrument that indicates distance traveled by a vehicle, such as a bicycle or automobile. The device may be electronic, mechanical, or a combination of the two. The word derives from the Greek words hodós and métron...

 and feeding this data to a computer that would keep track of the overall direction and distance back to the LM. There was also a Sun-shadow device that could give a manual heading based on the direction of the Sun, using the fact that the Sun moved very slowly in the sky.

Usage

Each rover was used on three traverses, one per day over the three-day course of each mission, with the individual performances logged as follows:
mission total distance total time longest single traverse maximum range from the LM
Apollo 15
Apollo 15
Apollo 15 was the ninth manned mission in the American Apollo space program, the fourth to land on the Moon and the eighth successful manned mission. It was the first of what were termed "J missions", long duration stays on the Moon with a greater focus on science than had been possible on previous...

 (LRV-001)
17.25 miles (27.76 km) 3 h 02 min 7.75 miles (12.47 km) 3.1 miles (5 km)
Apollo 16
Apollo 16
Young and Duke served as the backup crew for Apollo 13; Mattingly was slated to be the Apollo 13 command module pilot until being pulled from the mission due to his exposure to rubella through Duke.-Backup crew:...

 (LRV-002)
16.5 miles (26.55 km) 3 h 26 min 7.2 miles (11.59 km) 2.8 miles (4.5 km)
Apollo 17
Apollo 17
Apollo 17 was the eleventh and final manned mission in the American Apollo space program. Launched at 12:33 a.m. EST on December 7, 1972, with a three-member crew consisting of Commander Eugene Cernan, Command Module Pilot Ronald Evans, and Lunar Module Pilot Harrison Schmitt, Apollo 17 remains the...

 (LRV-003)
22.3 miles (35.89 km) 4 h 26 min 12.5 miles (20.12 km) 4.7 miles (7.6 km)


An operational constraint on the use of the LRV was that the astronauts must be able to walk back to the LM if the LRV were to fail at any time during the EVA (called the "Walkback Limit"). Thus, the traverses were limited in the distance they could go at the start and at any time later in the EVA. Therefore, they went to the farthest point away from the LM and worked their way back to it so that, as the life support consumables were depleted, their remaining walk back distance was equally diminished. This constraint was relaxed during the longest traverse on Apollo 17, based on the demonstrated reliability of the LRV and spacesuits on previous missions. A paper by Burkhalter and Sharp provides details on usage.

Deployment

Deployment of the LRV from the LM's Quadrant 1 bay by the astronauts was achieved with a system of pulleys and braked reels using ropes and cloth tapes. The rover was folded and stored in the bay with the underside of the chassis facing out. One astronaut would climb the egress ladder on the LM and release the rover, which would then be slowly tilted out by the second astronaut on the ground through the use of reels and tapes. As the rover was let down from the bay, most of the deployment was automatic. The rear wheels folded out and locked in place. When they touched the ground, the front of the rover could be unfolded, the wheels deployed, and the entire frame let down to the surface by pulleys.

The rover components locked into place upon opening. Cabling, pins, and tripods would then be removed and the seats and footrests raised. After switching on all the electronics, the vehicle was ready to back away from the LM.

Current locations

Four flight-ready rovers were manufactured. Three were transported to and left on the moon via the Apollo 15, 16, and 17, missions. The final rover was used for spare parts for Apollo 15, 16, and 17, following the cancellation of Apollo 18. As a result, the only lunar rovers on display are test vehicles, trainers, and models. The rover used on Apollo 15 was left on the lunar surface at Hadley-Apennine (26.10 N, 3.65 E). The rover used on Apollo 16 was left on the lunar surface at Descartes
Descartes Highlands
The Descartes Highlands is an area of lunar highlands located on the near side that served as the landing site of the American Apollo 16 mission in early 1972...

 (8.99 S, 15.51 E).

The rover used on Apollo 17 was left on the lunar surface at Taurus-Littrow (20.16 N, 30.76 E) and was seen again by the Lunar Reconnaissance Orbiter
Lunar Reconnaissance Orbiter
The Lunar Precursor Robotic Program is a program of robotic spacecraft missions which NASA will use to prepare for future human spaceflight missions to the Moon. Two LPRP missions, the Lunar Reconnaissance Orbiter and the Lunar Crater Observation and Sensing Satellite , were launched in June 2009...

 during passes in 2009 and 2011.
Several rovers were created for testing, training, or validation purposes. The engineering mockup is on display at the Museum of Flight
Museum of Flight
The Museum of Flight is a private non-profit air and space museum at King County International Airport , south of downtown Seattle, Washington. It was established in 1965 and is fully accredited by the American Association of Museums...

 in Seattle, Washington
Seattle, Washington
Seattle is the county seat of King County, Washington. With 608,660 residents as of the 2010 Census, Seattle is the largest city in the Northwestern United States. The Seattle metropolitan area of about 3.4 million inhabitants is the 15th largest metropolitan area in the country...

. The Qualification Test Unit is on display at the National Air and Space Museum
National Air and Space Museum
The National Air and Space Museum of the Smithsonian Institution holds the largest collection of historic aircraft and spacecraft in the world. It was established in 1976. Located in Washington, D.C., United States, it is a center for research into the history and science of aviation and...

 in Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....

  The rover used for vibration testing is on display in the Davidson Saturn V Center at the Marshall Space Flight Center
Marshall Space Flight Center
The George C. Marshall Space Flight Center is the U.S. government's civilian rocketry and spacecraft propulsion research center. The largest center of NASA, MSFC's first mission was developing the Saturn launch vehicles for the Apollo moon program...

 in Huntsville, Alabama
Huntsville, Alabama
Huntsville is a city located primarily in Madison County in the central part of the far northern region of the U.S. state of Alabama. Huntsville is the county seat of Madison County. The city extends west into neighboring Limestone County. Huntsville's population was 180,105 as of the 2010 Census....

. Additional test units are on display at the Johnson Space Center in Houston, Texas
Houston, Texas
Houston is the fourth-largest city in the United States, and the largest city in the state of Texas. According to the 2010 U.S. Census, the city had a population of 2.1 million people within an area of . Houston is the seat of Harris County and the economic center of , which is the ...

, and the Kennedy Space Center Visitors Complex in Cape Canaveral, Florida
Cape Canaveral, Florida
Cape Canaveral is a city in Brevard County, Florida, United States. The population was 8,829 at the 2000 census. As of 2008, the estimated population according to the U.S. Census Bureau was 10,147...

. Replicas of rovers are on display at the National Museum of Naval Aviation
National Museum of Naval Aviation
The National Museum of Naval Aviation is a military and aerospace museum located at Naval Air Station Pensacola, Florida. The museum opened in 1962....

 in Pensacola, Florida
Pensacola, Florida
Pensacola is the westernmost city in the Florida Panhandle and the county seat of Escambia County, Florida, United States of America. As of the 2000 census, the city had a total population of 56,255 and as of 2009, the estimated population was 53,752...

, the Evergreen Aviation & Space Museum in cMinnville, Oregon], and the Kansas Cosmosphere and Space Center
Kansas Cosmosphere and Space Center
The Kansas Cosmosphere and Space Center is a museum and educational facility in Hutchinson, Kansas that is best known for the display and restoration of spaceflight artifacts and educational camps...

 in Hutchinson, Kansas
Hutchinson, Kansas
Hutchinson is the largest city in and the county seat of Reno County, Kansas, United States, northwest of Wichita, on the Arkansas River. It has been home to salt mines since 1887, thus its nickname of "Salt City", but locals call it "Hutch"...

. A replica on loan from the Smithsonian Institution is on display at the Mission: Space
Mission: SPACE
Mission: SPACE is a motion simulator thrill ride at Epcot. It simulates what an astronaut might experience aboard a spacecraft on a mission to Mars, from the higher g-force of blastoff to the speculative hypersleep....

 attraction at Epcot
Epcot
Epcot is a theme park in the Walt Disney World Resort, located near Orlando, Florida. The park is dedicated to the celebration of human achievement, namely international culture and technological innovation. The second park built at the resort, it opened on October 1, 1982 and was initially named...

 at the Walt Disney World Resort
Walt Disney World Resort
Walt Disney World Resort , is the world's most-visited entertaimental resort. Located in Lake Buena Vista, Florida ; approximately southwest of Orlando, Florida, United States, the resort covers an area of and includes four theme parks, two water parks, 23 on-site themed resort hotels Walt...

 near Orlando, Florida
Orlando, Florida
Orlando is a city in the central region of the U.S. state of Florida. It is the county seat of Orange County, and the center of the Greater Orlando metropolitan area. According to the 2010 US Census, the city had a population of 238,300, making Orlando the 79th largest city in the United States...

.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK