Lunar Roving Vehicle
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The Lunar Roving Vehicle (LRV) is a battery-powered four-wheeled rover used on the Moon in the last three missions of the American Apollo program (15, 16, and 17) during 1971 and 1972. It is popularly called the Moon buggy, a play on the term "dune buggy".
Built by Boeing, each LRV has a mass of 462 pounds (210 kg) without payload. It could carry a maximum payload of 970 pounds (440 kg), including two astronauts, equipment, and cargo such as lunar samples, and was designed for a top speed of 6 miles per hour (9.7 km/h), although it achieved a top speed of 11.2 miles per hour (18.0 km/h) on its last mission, Apollo 17.
Each LRV was carried to the Moon folded up in the Lunar Module's Quadrant 1 Bay. After being unpacked, each was driven an average of 30 km, without major incident. These three LRVs remain on the Moon.
History
The concept of a
In 1956,
In 1959, Georg von Tiesenhausen conceived the lunar rover[2][3] as a four-wheel-drive vehicle with noninflated, flexible wheels.[4]
Early lunar mobility studies
In the February 1964 issue of Popular Science, von Braun, then director of NASA's Marshall Space Flight Center (MSFC), discussed the need for a lunar surface vehicle, and revealed that studies had been underway at Marshall in conjunction with Lockheed, Bendix, Boeing, General Motors, Brown Engineering, Grumman, and Bell Aerospace.[5] Saverio Morea was named LRV Manager at MSFC in 1961.[4]
Beginning in the early 1960s, a series of studies centering on lunar mobility were conducted under Marshall. 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 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 Marshall studies were based on this dual-launch assumption, allowing a large, heavy, roving vehicle.[6]
Grumman and Northrop, in the fall of 1962, began to design pressurized-cabin vehicles, with electric motors for each wheel. At about this same time Bendix and Boeing started their own internal studies on lunar transportation systems. Mieczysław Bekker, now with General Motors Defense Research Laboratories at Santa Barbara, California, was completing a study for NASA's Jet Propulsion Laboratory on a small, uncrewed lunar roving vehicle for the Surveyor program. Ferenc Pavlics, originally from Hungary, used a wire-mesh design for "resilient wheels," a design that would be followed in future small rovers.[7]
In early 1963, NASA selected Marshall 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 6,490–8,470 lb (2,940–3,840 kg) weight range, accommodating two men with their expendables and instruments for traverses up to two weeks in duration. In June 1964, Marshall awarded contracts to Bendix and to Boeing, with GM's lab designated as the vehicle technology subcontractor.[8] Bell Aerospace was already under contract for studies of Lunar Flying Vehicles.[9]
Even as the Bendix and Boeing studies were underway, Marshall was examining a less ambitious surface exploration activity, the LSSM. This would be composed of a fixed, habitable shelter–laboratory with a small lunar-traversing vehicle that could either carry one man or be remotely controlled. This mission would still require a dual launch with the moon vehicle carried on the "lunar truck".[10] Marshall's Propulsion and Vehicle Engineering (P&VE) lab contracted with Hayes International to make a preliminary study of the shelter and its related vehicle.[11] Because of the potential need for an enclosed vehicle for enlarged future lunar explorations, those design efforts continued for some time, and resulted in several full-scale test vehicles.
With pressure from Congress to hold down Apollo costs, Saturn V production was reduced, allowing only a single launch per mission. Any roving vehicle would have to fit on the same lunar module as the astronauts. In November 1964, two-rocket models were put on indefinite hold, but Bendix and Boeing were given study contracts for small rovers. The name of the lunar excursion module was changed to simply the lunar module, indicating that the capability for powered "excursions" away from a lunar-lander base did not yet exist. There could be no mobile lab — the astronauts would work out of the LM. Marshall also continued to examine uncrewed robotic rovers that could be controlled from the Earth.
From the beginnings at Marshall, the Brown Engineering Company of Huntsville, Alabama, had participated in all of the lunar mobility efforts. In 1965, Brown became the prime support contractor for Marshall's P&VE Laboratory. With an urgent need to determine the feasibility of a two-man self-contained lander, von Braun bypassed the usual procurement process and had P&VE's Advanced Studies Office directly task Brown to design, build, and test a prototype vehicle.[12] While Bendix and Boeing would continue to refine concepts and designs for a lander, test model rovers were vital for Marshall human factors studies involving spacesuit-clad astronauts interfacing with power, telemetry, navigation, and life-support rover equipment.
Brown's team made full use of the 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 Marshall Space Sciences Laboratory (SSL) was responsible for predicting surface properties, and Brown was also prime support contractor for this lab; Brown 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 small test rover, 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, Brown's vehicle became available for examining human factors and other testing. Marshall built a small test track with craters and rock debris where the several different mock-ups were compared; it became obvious that a small rover would be best for the proposed missions. The test vehicle was also operated in remote mode to determine characteristics that might be dangerous to the driver, such as acceleration, bounce-height, and turn-over tendency as it traveled at higher speeds and over simulated obstacles. The test rover's performance under one-sixth gravity was obtained through flights on a KC-135A aircraft in a
Lunar Roving Vehicle Project
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 Marshall, von Braun established a Lunar Roving Task Team, and in May 1969, NASA approved the Manned Lunar Rover Vehicle Program as a Marshall hardware development. The project was led by Eberhard Rees, Director of Research and Development at Marshall, who oversaw the design and construction of the rover,[13][14] with Saverio Morea acting as project manager.[4]
On 11 July 1969, just before the successful Moon landing of
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
The LRV was developed in only 17 months and performed all its functions on the Moon with no major anomalies. Scientist-astronaut Harrison Schmitt 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."[21]
The LRVs experienced some minor problems. The rear
The fender extension on the Apollo 17 LRV broke when accidentally bumped by
The
NASA's rovers, left behind, are among the
Features and specifications
The Apollo Lunar Roving Vehicle is a
Mass and payload
The Lunar Roving Vehicles have a
Wheels and power
The wheels were designed and manufactured by General Motors Defense Research Laboratories in
Maneuvering capability was provided through the use of front and rear steering motors. Each series-wound DC steering motor was capable of 0.1 horsepower (75 W). The front and rear wheels could pivot in opposite directions to achieve a tight turning radius of 10 feet (3 m), or could be decoupled so only front or rear would be used for steering. The wheels were linked in Ackermann steering geometry, where the inside tires have a greater turn angle than the outside tires, to avoid sideslip.
Power was provided by two 36-volt
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 and odometer 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
The LRV was used during the lunar surface operations of Apollo 15, 16 and 17, the J missions of the Apollo program. On each mission, the LRV was used on three separate EVAs, for a total of nine lunar traverses, or sorties. During operation, the Commander (CDR) always drove, while the Lunar Module Pilot (LMP) was a passenger who assisted with navigation.[31][32]
Mission | Total distance | Total time | Longest single traverse | Maximum range from the LM |
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Apollo 15 (LRV-1) | 17.25 miles (27.76 km) | 3 h 02 min | 7.75 miles (12.47 km) | 3.1 miles (5.0 km) |
Apollo 16 (LRV-2) | 16.50 miles (26.55 km) | 3 h 26 min | 7.20 miles (11.59 km) | 2.8 miles (4.5 km) |
Apollo 17 (LRV-3) | 22.30 miles (35.89 km) | 4 h 26 min | 12.50 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.[33]
Deployment
Astronaut deployment of the Lunar Roving Vehicle from the LM's open Quadrant 1 bay 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.[34]
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.[18]
Locations
Four flight-ready LRVs were manufactured, as well as several others for testing and training.[18] Three were transported to and left on the Moon via the Apollo 15, 16, and 17 missions (LRV-1 to 3), with the fourth (LRV-4) used for spare parts for the first three following the cancellation of Apollo 18.[18][35]
The rover used on Apollo 15 was left at
Since only the upper stages of the lunar excursion modules could return to lunar orbit from the surface, the vehicles, along with the lower stages were abandoned. As a result, the only lunar rovers on display are LRV-4, test vehicles, trainers, and mock-ups.[18]
- Lunar Roving Vehicle 4 (LRV-4)[1] is on display at the Kennedy Space Center Visitors Complex in Cape Canaveral, Florida.
- The Engineering Mockup [2], intended to design and integrate subsystems,Seattle, Washington.[38]
- The Qualification Test Unit [3], designed to study integration of all LRV subsystems,[18] is on display at the National Air and Space Museum in Washington, D.C.[39]
- The Vibration Test Unit [4], intended to study durability and handling of launch stresses,[18] is on display in the Davidson Saturn V Center at the U.S. Space & Rocket Center in Huntsville, Alabama.[40][41]
- The 1-gravity trainer [5] is on display at the Houston, Texas.[42]
As mentioned before, additional test units were built, like a static model, two 1/6 gravity models, a mass model.[18]
-
LRV-4,KSC Visitors Complex
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LRV 1-gravity trainer, Space Center Houston
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LRV engineering mockup, Museum of Flight
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LRV Vibration Test Unit, U.S. Space & Rocket Center
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LRV Qualification Test Unit, National Air and Space Museum
Replicas of rovers are on display at the
Media
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(from left to right) Astronauts John Young, Eugene Cernan, Charles Duke, Fred Haise, Anthony England, Charles Fullerton, and Donald Peterson await deployment tests of the Lunar Roving Vehicle (LRV) qualification test unit in building 4649 at the Marshall Space Flight Center (MSFC). November 1971.
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Apollo 16 Commander John Young drives Lunar Rover 002
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Dave Scott and Jim Irwin train on Earth to use the Lunar Rover on Apollo 15
See also
References
- ^ Bekker, Mieczyslaw G.; Theory of Land Locomotion, U. Michigan Press, 1956, and The Mechanics of Vehicle Mobility, U. Michigan Press, 1956 and 1962
- ^ "Georg von Tiesenhausen Oral History Interview" (PDF). nasa.gov. 29 November 1988. Retrieved 20 February 2024.
- ^ Roop, Lee (15 May 2015). "Georg von Tiesenhausen, 101 on Monday, owns spot as the last German rocket team member". AL.com. Retrieved 20 February 2024.
- ^ a b c Burkhalter, Bettye B.; Sharpe, Mitchell R. (1995). "Lunar Roving Vehicle: Historical Origins, Development, and Deployment" (PDF). nasa.gov. Journal of the British Interplanetary Society. Retrieved 20 February 2024.
- ^ von Braun, Wernher; "How We'll Travel on the Moon," Popular Science, February 1964, pp. 18–26
- ISBN 0-387-30774-5
- ^ Bekker, Mieczyslaw G., and Ferenc Pavlics; "Lunar Roving Vehicle Concept: A Case Study"; GMDRL Staff Paper SP63-205, May 1963
- ^ "Molab," Archived 12 October 2011 at the Wayback Machine Encyclopedia Astronautics
- ^ Courter, Robert; "What It's Like to Fly the Jet Belt," Popular Science, Nov. 1969, pp. 55–59, 190
- ^ APOLLO NEWS REFERENCE - LUNAR MODULE DERIVATIVES FOR FUTURE SPACE MISSIONS (PDF). Grumman.
- ^ "Lunar Shelter/Rover Conceptual Design and Evaluation," NASA CR-61049, Nov. 1964.
- ^ "Brown Builds Concept Of Lunar Vehicle," BECO Views, Vol. 9, Jan. 1966, p. 1
- ^ "Dr. Eberhard F. M. Rees". nae.edu. National Academy of Engineering. Retrieved 20 February 2024.
- ^ "Eberhard Rees". nasa.gov. Retrieved 20 February 2024.
- ^ From the Moon to the Balloon, New Jersey's Amazing Aviation History, HV Pat Reilly, 1992
- ^ Csillag, Ádám. "Interview with Ferenc Pavlics, lead developer of the Apollo Lunar Rovers". www.pulispace.com.
- ^ "Lunar Roving Vehicle," MSFC press release, 29 October 1969; Marshall Star, 3 November 1969
- ^ a b c d e f g h i j "The Apollo Lunar Roving Vehicle". NASA. 15 November 2005. Retrieved 16 May 2010.
- ^ a b Morea, Saverio F.; "The Lunar Roving Vehicle – Historical Perspective"; Proc. 2nd Conference on Lunar Bases and Space Activities, 5–7 April 1988; NASA Conference Publications 3166, Vol. 1, pp. 619–632.
- ^ Boyle, Rebecca (27 July 2021). "50 Years Ago, NASA Put a Car on the Moon". The New York Times. Retrieved 30 July 2021.
- ^ a b "The Apollo Lunar Roving Vehicle", NASA Document.
- ^ Lyons, Pete; "10 Best Ahead-of-Their-Time Machines", Car and Driver, Jan. 1988, p.78
- ^ NASA Reference Publication 1317, Jan 1994, Sullivan, Thomas A. "Catalog of Apollo Experiment Operations" pg. 68 "Experimental Operations During Apollo EVAs: Repairs to Experiments," NASA Document.
- ^ "Moondust and Duct Tape," NASA Document.
- ^ Baker, David; "Lunar Roving Vehicle: Design Report," Spaceflight, Vol. 13, July 1971, pp. 234–240
- ^ Kudish, Henry. "The Lunar Rover." Spaceflight. Vol. 12, July 1970, pp. 270–274
- ^ "Lunar Rover", brochure, Delco Electronics, Santa Barbara Operations,1972
- ^ "NASA Certificate for Ferenc Pavlics for Inventing the Resilient Wheel" (from Hungarian University of Engineering).
- ^ "Press Kit Apollo 15" (PDF). 15 July 1971. p. 96. Retrieved 28 October 2022.
- ISBN 0-387-30774-5
- ^ Jones, Eric. "Apollo 15 Mission Summary: Mountains of the Moon". Apollo Lunar Surface Journal.
- ISBN 9780857332677.
- ^ Burkhalter, Bettye B; Sharpe, Mitchell R (1995). "Lunar Roving Vehicle: Historical Origins, Development and Deployment". Journal of the British Interplanetary Society. 48 (5): 199–212.
- ^ "How did they pack the Apollo lunar rover? - collectSPACE: Messages". www.collectspace.com. Retrieved 15 February 2022.
- ^ "A Field Guide to American Spacecraft | LRV #4". 6 May 2012. Archived from the original on 6 May 2012. Retrieved 24 May 2023.
- ^ "NASA's Boeing-built moon rovers are granted Washington state landmark status". GeekWire. 24 October 2020. Retrieved 12 May 2021.
- State of Washington. 23 October 2020. Retrieved 12 May 2021.
- ^ "A Field Guide to American Spacecraft | LRV". 6 May 2012. Archived from the original on 6 May 2012. Retrieved 24 May 2023.
- ^ "A Field Guide to American Spacecraft | LRV". 6 May 2012. Archived from the original on 6 May 2012. Retrieved 24 May 2023.
- ^ "A Field Guide to American Spacecraft | LRV". 6 May 2012. Archived from the original on 6 May 2012. Retrieved 24 May 2023.
- ^ "Lunar Roving Vehicle, Vibration Test Unit | National Air and Space Museum". airandspace.si.edu. Retrieved 24 May 2023.
- ^ "A Field Guide to American Spacecraft | LRV". 6 May 2012. Archived from the original on 6 May 2012. Retrieved 24 May 2023.
- ^ a b "Lunar Roving Vehicles". Field Guide to American Spacecraft. Archived from the original on 8 August 2011. Retrieved 24 August 2009.
- ^ "Blast-Off on Mission: SPACE". Science and Technical Information, Spinoff. NASA. 2003. Archived from the original on 22 October 2003. Retrieved 24 August 2009.
External links
- Boeing Lunar Rover Vehicle Operations Handbook
- Article about the rover
- LRV Operations Handbook, Appendix A (Performance Data)
- Mobility Performance of the Lunar Roving Vehicle: Terrestrial Studies – Apollo 15 Results
- Lunar Rover in Operation Video
- Lunar and Planetary Rovers: The Wheels of Apollo and the Quest for Mars
- Apollo Lunar Roving Vehicle Documentation – Apollo Lunar Surface Journal
- Lunar Roving Vehicle at the Smithsonian National Air and Space Museum Archived 8 February 2022 at the Wayback Machine
- Lunar Roving Vehicle Collection, The University of Alabama in Huntsville Archives and Special Collections
- Ronald Lancaster Collection, The University of Alabama in Huntsville Archives and Special Collections Engineer's collection of photos and documents on the design and construction of the LRV.