NASA’s Lunar Rover: Everything You Need to Know

After an amazingly brief 17 months of designing and testing, the ‘Moon buggy’, the Lunar Roving Vehicle (LRV), or Lunar Rover was used from 1971-1972 as a key component of missions 15-17 of the Apollo Program. Created primarily to extend the range of terrain that the two Apollo crew members could explore during their stay on the Moon’s surface, four fully space-worthy lunar rovers along with seven test models were built in preparation for these J-Missions. The fourth sibling from the LRV family however never had the opportunity to enter space, as after the announced dissolution of the Apollo program it was relegated to providing spare parts for the other rovers.

 

The first successful rover to land on the Moon was in fact the Soviet Union’s robotic Lunokhod 1. Dismounting a ramp from the Luna 17 lander on  17 November 1970, for the following 10 months this eight-wheeled vehicle travelled over 10km of lunar surface transmitting useful geological data and imagery back to its remote-controllers on Earth. Solar-powered during the day, a radioisotope heater helped Lunokhod 1 endure the freezing-cold temperatures of the Moon at night. On the other side of the Pacific however from among various contenders including Grumman and Chrysler, the American-owned aircraft manufacturing giant Boeing secured the main Apollo LRV construction contract. Saverio “Sonny” Morea was appointed LRV program manager. General Motors were also brought on board to manage the development of the Moon buggy’s motors, wheels, and suspension.

 

image of LRV test vehicle

Apollo 16 astronauts John Young and Charles Duke test-drive a Rover Earth Trainer Unit in the Lunar Surface Simulator. The simulator helped develop the LRV navigation system and was an aid to engineers on Earth while the Apollo Missions were taking place. (Image credit: NASA)

 

Following in the most pragmatic traditions of spacecraft manufacture every part of the LRV had to be constructed from the lightest materials possible, so long as the choice of these materials did not compromise the buggy’s ability to withstand a load and the structural stresses of bumps during launch, touchdown, or navigation of lunar terrain. Likewise, every part of the Lunar Roving Vehicle had to be able to withstand the extreme temperature variations experienced on the surface of the Moon, ranging to 150 degrees below freezing. Worth 95 times the value of even a present day Rolls Royce, the first Lunar Rover emerged from the production line bearing a $38 000 000 price tag. Although lacking electric windows or convertible hood, the flight-compacted LRV package transformed before emerging as the four-wheeled Moon buggy we all recognise.

 

Image of LM general arrangement

This general arrangement diagram of a Lunar Module shows where the LRV was stowed. (Image credit: NASA)

 

 

How the LRV was unfolded and removed from the LM. Watch how it was done for real in the video below. (Image credit: NASA)

How the LRV was unfolded and removed from the LM. Watch it animated and how it was done for real in the videos below. (Image credit: NASA)

 


 

 

image of rover on moon

Commander Eugene A. Cernan test-driving an empty LRV on the Moon, shortly before loading-on equipment for Apollo 17 Mission’s first Extra-Vehicular Activity. (Image credit: NASA)

 

General arrangement of Lunar Rover Vehicle (Image credit: NASA)

General arrangement of Lunar Rover Vehicle (Image credit: NASA)

 

Weighing 204kg, equipped with one ¼hp electric motor per wheel, and powered by two 36V silver zinc non-rechargeable batteries, the Lunar Roving Vehicle could perform four wheel-steering, execute a U-turn within a three metre radius, and operate under a total vehicle weight of up to 659kg (104 stone). Mounted on the buggy’s chassis were: seatbelts; a T-handle driving control console with odometer detailing distance and bearing from the Lunar Module; a handbrake; a communications antennae; a navigational gyroscope orientated in relation to the Sun; a TV camera relaying footage back to Earth.

 

image_of LRV and Mt Hadley

With Mount Hadley beyond, Lunar Module Pilot Jim Irwin completes Apollo 15 Mission’s first EVA. Clearly visible are the lunar sample bags attached to the back of the Rover. (Image credit: NASA/David Scott)

 

Measuring 3.1m by 2.3m (wheelbase), the three Lunar Rovers were used to ferry scientific equipment, tools, life support consumables, lunar rock samples, and up to two occupants on their Extra-Vehicular Activities over a total of 90km of the Moon’s surface. The tool caddy was furnished with: a hammer, a sampling scoop, a brush, and a rake. Had new spacesuits enabling bending at the waist not been designed for Apollo Missions 15-17, no astronaut could have ever sat in a Lunar Rover. The new range of movement afforded by the suit facilitated kneeling and eased sample collection during EVA’s. Although LRVs were capable of running on just one battery in an emergency, the lunar astronauts always commenced their EVA by navigating the vehicles to the farthest calculated point from the lander module. This ensured that all subsequent stopping points of the traverse brought the astronauts increasingly close to the landing spacecraft, should the buggy have completely failed and returning by foot became a necessity.

 

image_of Stick and dashboard

Lunar Rover control panel on a replica LRV unit in the Museum of Flight, Seattle, Washington. (Image credit: Shannon Lucas via Wikimedia Commons)

 

The LRV astronaut operators of Apollo 15, 16, and 17 claimed that the lunar maps mounted on the LRV map holder did not resemble the Moon’s topography to any recognisable degree of accuracy. Moreover although quite an engineering feat to have achieved, the Lunar Rover navigation system was accurate at best only to within a range of 100 m. Scott and Irwin of Apollo 15 stated that if parked on a very steep slope the Roving Vehicle side-slipped downhill when the crew dismounted. Wire-mesh rather than rubber tyres were specially designed to improve grip where the buggy’s decreased lunar weight meant less frictional pressure could be exerted on the dusty lunar surface. 32 inches by 9, the tyre structure was formed from fine zinc-coated woven steel strands attached to a spun aluminium wheel hub. On the flat, these large wheels cleared the buggy’s undercarriage a good 12 inches from the lunar terrain.

 

A closer look: the titanium treads, zinc-coated steel wire-mesh tyre, and brown fender on the LRV replica displayed in the National Air and Space Museum, Washington. (Image credit: NASA via Wikimedia Commons)

 

With a pattern of steel chevrons attached to the mesh’s main contact surface, sufficient traction was achieved for the Lunar Roving Vehicles to climb 25 degree-inclined slopes and overcome obstacles up to a foot tall. A frequent compulsory activity the Rover astronauts performed during an EVA excursion was to brush any accumulating lunar dust from the upward-facing battery-cooling radiators and the lunar communications relay unit to guarantee the batteries and TV circuits would not overheat. However, although not intentional participants of some cosmic dirt-track rally, with the loss of a wheel fender during a lunar traverse, the Apollo 16 LRV crew covered themselves and the LRV console in sufficient lunar dirt potentially to qualify. The lunar maps these astronauts were forced to clamp in place as a makeshift fender are today on display at the National Air and Space Museum.

 

image_of LRV antenna

The high-gain communications antenna with the TV camera in the stowed position on the Apollo 15 Lunar buggy chassis. (Image credit: PD-USGOV-NASA via Wikimedia Commons)

 

 

On the Moon John Young (Apollo 16) achieved the LRV speed record of 11kmph which ‘J’-Mission astronauts indicated was quite fast enough in an environment of 1/6 Earth’s gravity. LRV2 operators Young and Duke claimed that travelling down Sun or into the Sun meant that they could only see craters when they were over them and Apollo 17 Rover Astronauts Cernan and Schmitt said that a sensation of “overturning” was experienced when the LRV3 bounced over them. Although TV coverage with the high gain antenna was not possible while the LRV was moving, audio communication was maintained with the low gain antenna. Despite the footage limitations, the TV camera could be controlled remotely from Earth, enabling panoramic filming of the astronauts carrying out scientific studies at the Rover’s stopping stations.

 

Apollo 16 Orion’s land and launch site: as only the ‘ascent stage’ (grey upper half) of the Lunar Module could leave the Moon’s surface to return to Earth, besides crew there was little room for a Lunar Rover. (Image credit: NASA via Wikimedia Commons)

 

Harrison Schmitt, one of the last astronauts to ever operate an LRV on the Moon attributed mission success to the Lunar Roving Vehicle: “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.”

 

Station 8, Cochise Crater: Apollo 17 crew’s footprints depart the Lunar Roving Vehicle for the last time. It’s only a machine, but it still looks lonely. (Image credit: NASA via Wikimedia Commons)

 

When you next gaze at the Moon, imagine three lunar buggies that were destined for an extra-terrestrial world, standing on silent vigil close to the Apollo lander sites where they were abandoned 40 years ago. For the final service an LRV rendered its Apollo Mission crew was to film the Lunar Module and its crew blast-off from the landing platform and ascend back into space. Where others had failed, Apollo 17, the culmination of all previous J-Missions and the last chapter of the Apollo program, succeeded in attaining this eagerly- awaited footage.

 

 

(Please note that Armagh Planetarium is not affiliated with NASA or any company which built components of the LRV. We regret that we cannot help you trace, contact  or research people who worked on this project.)
FURTHER READING

LUNAR ROVING VEHICLE OPERATIONS HANDBOOK (link)

 

 

(Article by Nick Parke, Education Support Officer, updated 1 February 2016)