Editing Lunar Roving Vehicle (section)

=== 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.<ref>von Braun, Wernher; [https://books.google.com/books?id=qS0DAAAAMBAJ&pg=PA18 "How We'll Travel on the Moon,"] ''Popular Science'', February 1964, pp. 18–26</ref> [[Saverio "Sonny" Morea|Saverio Morea]] was named LRV Manager at MSFC in 1961.<ref name=":0" />
[[File:Lander Rover Apollo Mission.jpg|thumb|MOLAB, NASA Illustration, 1960]]
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. <ref>Young, Anthony; ''Lunar and planetary rovers: the wheels of Apollo and the quest for Mars''; Springer, 2007, pp. 30–57; {{ISBN|0-387-30774-5}}</ref>

Grumman and Northrop, in late 1962, began to design pressurized-cabin vehicles, with electric motors for each wheel. At about this same time, Bendix and Boeing started their internal studies on lunar transportation systems. [[Mieczysław G. Bekker|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.<ref>Bekker, Mieczyslaw G., and Ferenc Pavlics; "Lunar Roving Vehicle Concept: A Case Study"; GMDRL Staff Paper SP63-205, May 1963</ref>

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 {{convert|6490|-|8470|lb|kg|abbr=on}} 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 Boeing, with GM's lab designated as the vehicle technology subcontractor.<ref>[http://www.astronautix.com/craft/molab.htm "Molab,"] {{webarchive|url=https://web.archive.org/web/20111012091139/http://astronautix.com/craft/molab.htm|date=12 October 2011}} ''Encyclopedia Astronautics''</ref> Bell Aerospace was already under contract for studies of Lunar Flying Vehicles.<ref>Courter, Robert; [https://books.google.com/books?id=NyoDAAAAMBAJ&pg=PA55 "What It's Like to Fly the Jet Belt,"] ''Popular Science'', Nov. 1969, pp. 55–59, 190</ref>

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".<ref>{{Cite book |url=https://history.nasa.gov/alsj/LM23_LM_Derivatives_LMD1-13.pdf |title=APOLLO NEWS REFERENCE - LUNAR MODULE DERIVATIVES FOR FUTURE SPACE MISSIONS |publisher=Grumman}}</ref> 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.<ref>[https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19650014414_1965014414.pdf "Lunar Shelter/Rover Conceptual Design and Evaluation,"] NASA CR-61049, Nov. 1964.</ref>  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.

[[File:Driving Distances on Mars and the Moon.png|thumb|left|Comparison of distances driven by various wheeled vehicles on the surface of the [[Moon]] and [[Mars]]]]

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 [[Apollo Lunar Module|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.<ref>"Brown Builds Concept Of Lunar Vehicle," ''BECO Views'', Vol. 9, Jan. 1966, p. 1</ref> 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's "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 [[Rollover protection structure|roll bar]] gave protection from overturning 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 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 [[Reduced gravity aircraft|Reduced Gravity]] [[parabolic trajectory|parabolic]] maneuver; among other things, the need for a very soft wheel and suspension combination was shown. Although Pavlics' wire-mesh wheels were not initially available for the reduced gravity tests, the mesh wheels were tested on various soils at the [[Waterways Experiment Station]] of the [[United States Army Corps of Engineers|U.S. Army Corps of Engineers]] at [[Vicksburg, Mississippi]]. Later, when wire-mesh wheels were tested on low-g flights, the need for wheel fenders to reduce dust contamination was found. The model was also extensively tested at the U.S. Army's [[Yuma Proving Ground]] in [[Arizona]], as well as the Army's [[Aberdeen Proving Ground]] in [[Maryland]].