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Apollo LRV

LRV Drawing

LRV Drawing
Credit: NASA

American manned lunar rover. The Apollo Lunar Roving Vehicle was one of those sweet pieces of hardware that NASA and its contractors seemed to be able to develop so effortlessly during the short maturity of the Apollo program. The Lunar Rover was the only piece of equipment from NASA's ambitious post-Apollo lunar exploration plans to actually fly in space, being used on Apollo missions 15, 16, and 17 in 1971-1972. The design was based on three years of studies for light, two-crew, open-cockpit 'Local Science Survey Modules'. Although Bendix built a prototype, Boeing ended up with the production contract.

AKA: Lunar Roving Vehicle. Status: Operational 1971. Gross mass: 208 kg (458 lb).

The collapsible 208 kg battery-powered rover could take two astronauts, 55 kg of scientific equipment, and 27 kg of lunar samples over a cumulative distance of 92 kilometers during one lunar day.

Weighing about 208 kilograms (457 pounds), Earth weight when deployed on the Moon, the LRV could carry a total payload of about 490 kilograms (1,080 pounds), more than twice its own weight. The payload included two astronauts and their portable life support systems (about 353 kilograms; 800 pounds), 45.4 kilograms (100 pounds) of communications equipment, 54.5 kilograms (120 pounds) of scientific equipment and photographic gear, and 27.2 kilograms (60 pounds) of lunar samples.

The LRV was designed to operate for a minimum of 78 hours during :the lunar day. It could make several exploration sorties to a cumulative distance of 92 kilometers (57 miles). The maximum distance the LRV was permitted to range from the lunar module was approximately 9.7 kilometers (six miles), the distance the crew could safely walk to the LM in the unlikely event of a total LRV failure. This walk-back distance limitation was based upon the quantity of oxygen and coolant available in the astronauts' portable life support systems. This area contained about 290 square kilometers (113 square miles) available for investigation, 10 times the area that could be explored on foot.

The vehicle could negotiate obstacles 30.5 centimeters (one foot) high, and cross crevasses 70 centimeters wide (28 inches). The fully loaded vehicle could climb and descend slopes as steep as 25 degrees, and park on slopes up to 35 degrees. Pitch and roll stability angles were at least +-45 degrees, and the turn radius was three meters (10 feet).

Both crewmen sat so the front wheels were visible during normal driving. The driver used an on-board dead reckoning navigation system to determine direction and distance from the lunar module, and total distance traveled at any point during a traverse.

The LRV consisted of five major systems: mobility, crew station, navigation, power, and thermal control. Secondary systems included the deployment mechanism, LM attachment equipment and ground support equipment.

The aluminum chassis was divided into three sections that supported all equipment and systems. The forward and aft sections fold over the center one for stowage in the LM. The forward section held both batteries, part of the navigation system, and electronics gear for the traction drive and steering systems. The center section held the crew station with its two seats, control and display console; and hand controller. The floor of beaded aluminum panels could support the weight of both astronauts standing in lunar gravity. The aft section held the scientific payload.

Auxiliary LRV equipment included the lunar communications relay unit (LCRU) and its high and low gain antennas for direct communications with Earth, the ground commanded television assembly (GCTA), a motion picture camera, scientific equipment, tools, and sample stowage bags.

Mobility System

The mobility system was the major LRV system, containing the wheels, traction drive, suspension, steering, and drive control electronics subsystems.

The vehicle was driven by a T-shaped hand controller located on the control and display console post between the crewmen. Using the controller, the astronaut maneuvered the LRV forward, reverse, left and right.

Each LRV wheel had a spun aluminum hub and a titanium bump stop (inner frame) inside the tire (outer frame). The tire was made of a woven mesh of zinc-coated piano wire to which titanium treads were riveted in a chevron pattern around the outer circumference. The bump stop prevented excessive inflection of the mesh tire during heavy impact. Each wheel weighed 5.4 kilograms (12 pounds) on Earth and was designed to be driven at least 180 kilometers (112 miles). The wheels were 81.3 centimeters (32 inches) in diameter and 22.9 centimeters (nine inches) wide.

A traction drive attached to each wheel had a motor harmonic drive gear unit, and a brake assembly. The harmonic drive reduced motor speed at an 80-to-1 rate for continuous operation at all speeds without gear shifting. The drive had an odometer pickup (measuring distance traveled) that sent data to the navigation system. Each motor developed 0.18 kilowatt (1/4-horsepower) and operated from a 36-volt input.

Each wheel had a mechanical brake connected to the hand controller. Moving the controller rearward de-energized the drive motors and forced brake shoes against a drum, stopping wheel hub rotation. Full rear movement of the controller engaged and locked a parking brake.

The chassis was suspended from each wheel by two parallel arms mounted on torsion bars and connected to each traction drive. Tire deflection allowed a 35.6-centimeter (11-inch) ground clearance when the vehicle was fully loaded and 43.2 centimeters (17 inches) when unloaded.

Both front and rear wheels had independent steering systems that allowed a "wall-to-wall" turning radius of 3.1 meters (122 inches), exactly the vehicle length. If either set of wheels had a steering failure, its steering system could be disengaged and the traverse could continue with the active steering assembly. Each wheel could also be manually uncoupled from the traction drive and brake to allow "free wheeling" about the drive housing.

Pushing the hand controller forward increased forward speed; rear movement reduced speed. Forward and reverse were controlled by a knob on the controller's vertical stem. With the knob pushed down, the controller could only be pivoted forward; with it pushed up, the controller could be pivoted to the rear for reverse.

Crew Station

The crew station consisted of the control and display console, seats, seat belts, and armrest, footrests, inboard and outboard handholds, toeholds, floor panels, and fenders.

The control and display console was separated into two main parts: The top portion held navigation system displays; the lower portion contained monitors and controls. Attached to the upper left side of the console was an attitude indicator that showed vehicle pitch and roll.

At the console top left was a position indicator. Its outer circumference was a large dial that showed vehicle heading (direction) with respect to lunar north. Inside the dial were three digital indicators that showed bearing and range to the LM and distance traveled by the LRV. In the middle of the console upper half was a Sun compass device that was used to update the LRV's navigation system. Down the left side of the console lower half were control switches for power distribution, drive and steering, and monitors for power and temperature. A warning flag atop the console was set whenever a temperature went above limits in either battery drive motor.



Subtopics

Bendix LSSM American manned lunar rover. Study 1965. The Bendix LSSM lunar rover design of October 1965 had 4 wheels. and a range of 400 km with a crew of 2 on a 14 day traverse.

Boeing LSSM American manned lunar rover. Study 1965. The Boeing LSSM lunar rover design of June 1965 had 4 wheels of 1.2 or 1.6 m diameter. and a range of 200 km with a crew of 2 on a 14 day traverse.

LSSM American manned lunar rover. Study 1968. The Bendix Local Science Survey Module was a forerunner of the Lunar Rover. The LSSM was a small size vehicle used to support a local manned survey. It was proposed for delivery with an LM Shelter.

Family: Lunar Rovers, Moon. Country: USA. Launch Vehicles: Saturn V. Agency: Boeing. Bibliography: 16, 2487, 2488, 2489, 2490, 2491, 2492, 2493, 2494, 2495, 2496, 2497, 2498, 2499, 2500, 2501, 2502, 2503, 2504, 2505, 2506, 2507, 26, 66.
Photo Gallery

LRV 3 ViewLRV 3 View
Credit: NASA


Lunar roverLunar rover
Credit: NASA



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