Chapter 8
The Vietnam Era and Beyond: Mobility and Environmental Studies, 1963-1978  back arrow

Mobility and Environmental Administration

Thumbnail for Woodland G. ShockleyWoodland G. Shockley provided leadership for the Mobility and Environmental Division from its inception in 1963 until its merger back into the Geotechnical Laboratory successor of the Soils Division in 1978. He, in fact, served as the organization's only Chief. Like his counterparts in the Soils Division, Turnbull and Sale, Shockley took advantage of in-house expertise through his administrative appointments. In 1964 Sterling J. Knight rose from the position of Army Mobility Research Branch Chief to become Shockley's Assistant Division Chief. He served in that capacity until 1973. Dean R. Freitag succeeded Knight as AMRB Chief, joining Warren E. Grabau and Adam A. Rula as branch heads within the division. When Freitag became WES Assistant Technical Director in 1970, Knight served in a dual capacity as Assistant Division Chief and Chief, AMRB. In 1972 Station Director Colonel Ernest D. Peixotto changed the name of the Mobility and Environmental Division to Mobility and Environmental Systems Laboratory (MESL not to be confused with the acronym for "membrane-enveloped structural layers"). The following year Freitag left the Station, and a two-branch arrangement continued under Grabau and Rula. Bob O. Benn, also a long-time WES employee, replaced Grabau in 1975. Rula continued his remarkable career at WES until retirement in 1980. He served as a consultant until 1991.

International Society for Terrain Vehicle Systems

Thumbnail for C. J. NuttallIncreased interest in mobility and trafficability studies on an intercontinental scale led to the founding of the International Society for Terrain Vehicle Systems. From the organization's inception, WES personnel played important roles. In 1964 the first issue of the society's organ, Journal of Terramechanics, carried articles by John L. McRae and Knight and by Clifford J. Nuttall, who had relocated to WES.1 McRae also contributed a major technical article, "Theory for a Towed Wheel in Soil," later in the same year.2 Future issues featured papers by Freitag, M.E. Smith, Edgar S. Rush, John H. Shamburger, and A.J. Green of WES, in addition to further articles by McRae, Knight, and Nuttall.3 In 1965 the second year of publication Freitag became Associate Editor of the Journal, a position he still held in 1993.4 In recognition of Knight's many contributions, the society made him a Fellow Member in 1975, three years after his retirement from WES.5

The MERS Project

The WES Mobility and Environmental Division dedicated many of its early activities to the war in Southeast Asia. Paramount was the Mobility Environmental Research Study (MERS), a project requested by the Army Materiel Command in early 1962 (see Chapter 5). MERS called for an extensive study of the environment of Thailand, especially as it pertained to the design and employment of materiel and materiel systems. Because Thailand was a member of the Southeast Asia Treaty Organization (SEATO) and an ally of the United States, operations in that country could be conducted unimpeded and with the support of a friendly government. Project planners noted that military environments in Thailand were in many ways similar to those of Vietnam, so that analogous comparisons could be made that might assist military operations in the latter.

WES, as managing agency of MERS, took immediate steps to regroup its capabilities. A separate MERS Branch within the Mobility and Environmental Division took shape, headed by Rula. Within the Branch, a stateside unit was responsible for planning and managing all activities, while a Thailand detachment gathered field data. Soils Division personnel provided expertise when needed, especially from the Geology Branch. Numerous contract personnel and organizations and local authorities also contributed. Plans called for collection and quantification of data according to the six "families of environmental factors" pioneered in the WES Military Evaluation of Geographic Areas (MEGA) program. These involved (1) surface geometry, (2) surface composition, (3) hydrologic geometry, (4) vegetation, (5) animal life, and (6) weather and climate (see Chapter 5).6

From May to October 1962, Rula supervised formation and opening-phases activities of the Thailand unit. Other on-site WES personnel included Grabau and W.K. Dornbusch, who joined representatives from the Army Transportation Board, the Army Land Locomotion Research Laboratory, the Army Military Geology Branch, the Advanced Research Projects Agency, and local officials in an impressive array. Rula eventually spent fifteen months in Southeast Asia, living in hotels, houses, police stations, and occasionally tents, some in areas noted for leeches and liver flukes; C-rations often supplemented local fare.7 Only five years earlier, in an extreme of climatic contrasts, he had participated in WES mobility studies on the Greenland icecap.

As a typical first step, the MERS study began with publication of a literature survey of existing data on various aspects of the Thai environment. This provided an quick overview, although a thorough study of over 1,600 sources was not completed until 1965.8 In rapid succession, by May 1963 a further series of preliminary reports presented observations and data on a large number of sites in Thailand. These represented various environments ranging from rice-paddied lowlands to heavily forested highlands. Environmental factor families provided a basis of organization.9

A second, more extensive MERS phase occupied Rula's personnel through 1964 and 1965. Seven primary study areas with approximately 2,400 sampling sites yielded data obtained by empirical methods: soil sampling, terrain survey, hydrographic mapping, vegetation analysis, and others. Vehicle tests employed conventional and experimental types. Extensive aerial photographs supplemented ground observations.10

Studies directed by the MERS stateside contingent complemented methods and observations in Thailand. A major project for predicting cross-country vehicle performance, conducted largely at WES research sites in Puerto Rico and Panama, led to acceptance of a more refined analytical model with only four environmental factor families rather than the six of previous MEGA and MERS studies. Animal life and weather and climate were no longer incorporated in MERS reports.11 Methods to quantitatively describe terrain obstacles were improved by test observations on military reservations in the United States.12 Because it was anticipated that extensive rice paddies would cause mobility problems in Southeast Asia, J.G. Kennedy and Rush studied rice fields at twenty-two locations in Arkansas and Louisiana.13

The primary MERS report, published as an eight-volume series between 1966 and 1968, provided exhaustive information on Southeastern Asian environments as pertaining to military mobility.14 Complementary publications concentrated on a more inclusive analysis of selected soils from Thailand and their trafficability classifications.15 Military tacticians applied data and methods derived from the MERS studies on a continuous basis in Vietnam.

Non-Traditional Vehicles

Mobility requirements in Southeast Asia often involved marshy areas of very low trafficability in addition to riverine environments. Army planners therefore sought vehicles that could operate effectively in such non-traditional realms. Development of vehicles that could function in both waterborne and low trafficability soils environments could be particularly beneficial. Because conventional wheeled vehicles had little chance of meeting such criteria, designers primarily civilian produced several non-wheeled vehicles, all revolutionary in concept, in attempts to meet military demands.

WES evaluations of non-traditional vehicles began in 1963 with tests of Jiger and Fisher vehicles near Parry Sound, Ontario, Canada. Both were small, amphibious units produced by private manufacturers, primarily for use by hunters, fishermen, and other outdoorsmen who required transportation across water and unstable terrain. In addition to WES, the Organic and Associated Terrains Research Unit of McMaster University, Hamilton, Ontario, and the U.S. Army Land Locomotion Research Laboratory participated in observations. WES reports concluded that the Jiger in particular had potential for military use. The 240-pound vehicle, which ran on six powered wheels or on tracks superimposed on the wheels, carried a 300-pound payload over the poorest terrain conditions, notably muskeg. Previous tests had proved its worth in a tropical environment in Panama and also in snow. The Army consequently, based on WES recommendations, purchased several of the machines for tests in conjunction with Rula's MERS activities in Thailand.16

WES also conducted performance tests of prototype XM759 amphibious logistical carriers for the Marine Corps from 1967 to 1970. The 1.5-ton vehicle travelled on thirty-four low-pressure pneumatic tires that revolved on either side of the vehicle via a pneumatic track, thus combining advantages of both wheeled and tracked vehicles. Investigations concentrated on swampy areas near Richmond and Petersburg, Virginia, and on sites near Vicksburg where conditions were similar to those of the Mekong Delta, Vietnam. Amphibious tests at the Station involved driving the vehicle across the WES lake and up muddy slopes upon exiting the water. Results suggested that major modifications were necessary before the vehicle could be adopted as a military standard.17

Thumbnail for Marsh screw amphibian test Other vehicles evaluated by the Mobility and Environmental Division were much less conventional. In 1964 WES tested the Marsh Screw Amphibian, the product of a revolutionary design by Chrysler Corporation. Rather than wheels or tracks, the Marsh Screw relied for locomotion on two large Archimedean screw-type devices that extended the length of the vehicle on each side. Powered by an automobile engine, the counterrotating screws propelled the vehicle through water and marsh terrain adequately, but failed miserably on soil surfaces, especially sand. The average maximum speed attained on test lanes was a meager 1.6 miles per hour.18

Thumbnail for Riverine utility craftDisappointing results in the Marsh Screw tests did not end ambitions for screw-type mobility systems. In 1969 Chrysler produced a much larger vehicle, the Riverine Utility Craft (RUC) for the Navy. The RUC traveled on two aluminum rotors, 39 inches in diameter and powered by twin Chrysler 440-cubic-inch automobile engines. A WES test program requested by the Navy imitated the earlier Marsh Screw investigations, employing sites in south Louisiana similar to Southeast Asian environments. Maximum speed attained on water reached an impressive 15.7 knots, while speeds on marshy terrain improved to nearly 25 knots. However, speeds on firm soils proved disappointing, reaching only 3.6 knots. In later tests in rice paddies, RUCs tended to hang up on earthen dikes. Despite efforts to the contrary, non-wheeled vehicles failed to compete seriously with their more conventional wheeled and tracked counterparts.19

Lunar Rover

While many activities of Shockley's division concentrated on the soggy terrain of Southeast Asia, by the late 1960s an entirely new area of investigation emerged: the arid surface of the moon. President John F. Kennedy in 1961 challenged Americans with the goal of "landing a man on the moon and safely returning him to earth" before the end of the decade. In an unprecedented effort in peacetime, NASA made the President's challenge a reality through the Apollo program.

Long before Neil Armstrong took the first steps on the moon, engineers had pondered the nature of the lunar environment and the mobility challenges it would pose.20 Early in the Apollo program, NASA planners saw the need for vehicles that could traverse the moon's surface. Such vehicles must cope with unknown soil conditions, slopes, and a gravitational pull only one-sixth that of earth. As early as 1962 NASA produced performance criteria for a lunar roving vehicle (LRV), although no empirical data existed as to the trafficability conditions which might be encountered.21

By 1965 the preliminary Ranger project had viewed the moon's surface telescopically from orbiting spacecraft, and the following Surveyor venture resulted in the first soft lunar landing in 1966. Surveyor, in fact, deployed a "Surface Sampler" that made the first extra-terrestrial soil mechanics tests. Photographic and other radio transmitted data from these endeavors provided valuable information on the lunar surface, as did photographic panoramic scans by the Russian spacecraft Luna 9.22 However, it was not until the landing of a manned spacecraft on the moon Apollo 11 in July 1969 that astronauts took actual samples of lunar soil and brought them back to earth. Among the first instruments used to test the extraterrestrial landing site was a simple cone penetrometer. The crew of Apollo 12 returned more detailed observations and samples in November of the same year.23

Thumbnail for Lunar roving vehicle 
wheel tested at WES and selected for moon landingsIn the spring of 1969, just prior to the Apollo flights, NASA awarded a contract to Boeing to build four LRVs for use by April 1971.24 NASA concurrently requested that WES conduct mobility investigations of a range of prototype vehicle running gears, with the goal of establishing the best mobility characteristics for such vehicles. The Mobility and Environmental Division's Mobility Research Branch, first under Freitag and then under Knight, performed primary research. Klaus-Jurgen Melzer was largely responsible for testing design and data interpretation.

Because samples taken from the moon were too small to use in trafficability tests, the WES investigation relied on available materials to simulate lunar soils. NASA officials selected a wind-deposited, fine dune sand from the desert near Yuma, Arizona, and a crushed basalt from Napa Valley, California. Each possessed ranges of cohesive and frictional properties believed to include the range of lunar soil properties. After transportation of substantial quantities of both to WES, the Mobility Research Branch subjected these lunar soil simulants to triaxial, shear, penetrometer, density and moisture, trenching, and other tests typical of conventional mobility studies. Technicians then placed prepared soil samples in test bins to a depth of approximately 32 inches and plowed the soil with a seed fork to a depth of 12 inches. For loose, moonlike conditions, no compaction was necessary. Tests often employed two soil bins coupled end to end when longer lanes were needed.25

Conventional pneumatic wheel and tire configurations were unsuited to lunar conditions of temperature extremes and low atmospheric pressure. The powdery surface also presented unusual problems of traction, so that more innovative wheel designs were necessary. NASA in 1969 furnished three unorthodox wheels to WES for evaluation: Boeing-General Motors, Bendix, and SLRV models. The SLRV model was standard equipment on a six-wheel Surveyor Lunar Roving Vehicle produced by the Jet Propulsion Laboratory (JPL) of Pasadena, California. JPL provided one of the vehicles to WES for its testing program. Grumman Aircraft Engineering Corporation also submitted a fourth wheel design. Investigations included a standard pneumatic tire for purposes of comparison.

Laboratory tests imitated standard trafficability/mobility tests for non-lunar soils and vehicles. The cantilevered test carriage in the WES small-wheel testing facility supplied power for single-wheel tests during passes through soil samples, while multiple-wheel tests used the six-wheel SLRV and a four-wheel custom-made cart. WNRE, Inc., originally fabricated the latter as a light marsh buggy. Power sources, weights, slopes, and other variables reproduced anticipated lunar conditions as closely as possible.26

The Boeing-GM model showed exceptional promise. It consisted of a woven wire design of 0.033-inch-diameter zinc-coated music wire, with titanium chevrons riveted to the wire mesh to provide enhanced traction. After WES validation of the general design in early tests, Boeing made minor improvements that WES continued to evaluate through 1970 and into 1971.27 NASA approved and accepted a version that Boeing incorporated into its final product in the spring of 1971. In late July Apollo 15 landed on the moon with the first operational LRV: the "fourth astronaut." Freitag, Melzer, and A.J. Green witnessed the event from the control room of the Marshall Space Flight Center in Huntsville, Alabama. The vehicle's performance in over eighteen hours of operation, described by NASA Flight Director Gerald Griffin as "fantastic," was at least partly due to its WES-validated running gear. Benefiting from increased mobility, Apollo 15 provided a geological bonanza for earth-bound scientists.28

Thumbnail for Elastic Loop Mobility System tested at WESIn anticipation of further lunar exploration and the first expedition to Mars, the Lockheed Corporation in 1971 developed an Elastic Loop Mobility System (ELMS). Prototypes consisted of an elastic loop approximately 6 feet long and 14 inches wide, formed from a continuous strip of high-strength metal or fiber-reinforced material. The configuration potentially provided advantages of a tracked system such as reduced and more uniform ground contact pressure which would result in improved soft-soil performance and superior obstacle negotiation. NASA again requested that WES perform evaluations. Tests conducted through 1973 encouraged further ELMS development, but as U.S. commitment to the space program waned, efforts were suspended.29

AMC-71 Mobility Model

In 1971 the Mobility and Environmental Division began work on a long-term project that eventually incorporated, then expanded on, all mobility, trafficability, and military environmental knowledge to date. For the next two decades and beyond this venture remained the focus of the organization's existence.

By the 1960s the study of vehicle-terrain relationships was an indispensable element in military planning. Knowledge, much of it derived from WES studies, had advanced to the point that some predictions were possible that permitted analysis of the effect of a complete terrain complex on mobility. By decade's end, in fact, WES researchers had produced a relatively detailed analytical model for predicting cross-country vehicle performance that incorporated and quantified the elements of vegetation, surface geometry, surface composition, hydrologic geometry, and other factors such as driver vision and vehicle speed.30

In addition to empirical relationships established by field investigations, more theoretical interpretations and predictions were evolving, especially with the aid of computers.31 A revolutionary WES study beginning in 1968 for the first time used a mathematical model of a pneumatic tire to compute forces transmitted through the tire to a vehicle axle. Digital computer simulations in a second phase of the study ran a vehicle at selected speeds over terrain profiles with various levels of roughness. Computer programs generated the terrain profiles with a desired spectrum of quantified variables. Results from over 300 field tests reinforced computer simulations.32 A related study, performed partly in Thailand, presented a tentative selection of standard terrains that could be used in evaluating relative performances of vehicles and a first-generation computer program for predicting speed performance.33

In 1971 the AMC implemented an inclusive ground mobility research program. A review of military requirements for vehicle mobility indicated a common need for an analytical procedure for assessing off-road vehicle performance. Consequently, the AMC requested that all three Army laboratories engaged in ground mobility research WES, the U.S. Tank-Automotive Command (TACOM) in Detroit, and the U.S. Army Engineer Cold Regions Research and Engineering Laboratory (CRREL) cooperate to achieve a common goal. As a first step, all engineering knowledge of fundamental terrain-vehicle-driver interactions was to be incorporated into a first-generation computerized ground mobility model called the AMC-71 Mobility Model, or simply AMC-71.

WES was already compiling and evaluating data developed in over twenty-five years of mobility research. Rula and Nuttall in 1971 completed a study, canvassing a mass of literature, that analyzed existing or proposed ground mobility models, selected those which merited more detailed examination, and presented a list of guidelines for the future development of a research program.34 This formed the basis of the AMC-71 initiative.

AMC-71 and its successors were founded on the premise that all essential factors involved in mobility of a given vehicle in a given environment could be quantified and coordinated more precisely than in previous attempts. In overall structure, the AMC model recognized three primary elements in the mobility equation: vehicle, terrain, and driver. Each required independent analysis and quantification. Data bases for military vehicles included specifications of geometric and mechanical characteristics that could be computerized easily. Terrain modules consisted of relatively small "patches" characterized according to thirteen measurements. These reflected the type and strength of surface materials, slope, surface roughness, obstacles, vegetation, and other factors. Nine further measurements quantified linear obstacles in an area such as streams according to width, depth, velocity, type and strength of surface materials, and other elements. Combined terrain factors, expressed on detail maps, presented an overall mathematical interpretation of any given area. Little data was available concerning driver-related factors such as imposition of acceleration, braking, visibility, and the effects of shock and vibration. Project creators anticipated that, upon quantification and computerization, data describing the three mobility elements could be coordinated to accurately predict vehicle behavior in areas where data were available.

After completion of the basic AMC-71 model, WES began a three-year program of field tests to compare computer predictions with actual vehicle performance.35 Five vehicles selected for testing afforded a range of mobility characteristics: an M151 jeep, M35A2 truck, M113A1 armored personnel carrier, M48 tank, and M60 tank. Test sites at Fort Sill, Oklahoma; Yuma Proving Ground, Arizona; Eglin Air Force Base, Florida; Houghton, Michigan; and Fort Knox, Kentucky, provided a variety of well-mapped terrains. Data indicated that computer model predictions were about seventy percent accurate. Shortcomings in quantification of surface roughness, obstacle override, vegetation influence, and driver performance especially affected results.36 Still, observers viewed the AMC-71 project as a major success because it was intended to be only the first generation of a lengthy family tree.

Army Mobility Model-75

The AMC's second-generation product, Army Mobility Model-75 (AMM-75), augmented the basic precepts of its predecessor. Reflecting more refined quantification of terrain areas, AMM-75 described each areal unit through twenty-two mathematically independent terrain factors, as compared to the thirteen of AMC-71. Ten classification factors for linear features and an additional nine for roads further enhanced the model. Whereas AMC-71 assumed that all running gears of a vehicle were powered, geometrically identical, and equally loaded, AMM-75 could simulate vehicles and vehicle combinations having various configurations of powered, braked, and towed wheels and tracks, variously loaded. AMM-75 further contained equations that allowed simulations of travel across slippery soils, muskeg, and snow in addition to the fine-and coarse-grained soils covered in AMC-71.37

Also of major significance, AMM-75 provided more detailed and accurate quantification of driver behavior, an area poorly interpreted in the previous model. Nuttall opined that the driver in the AMC-71 model was assumed to be "both omniscient and somewhat mad.38 "This had led to overestimation of vehicle speeds in field trials, partly because drivers were understandably hesitant to run over trees and other obstacles that caused no fear to computers. Pioneer studies of the effect of vehicle dynamics on driver performance, begun by the Mobility and Environmental Division in the late 1960s and continuing into the 1970s, furnished improved data for AMM-75.39 From field data and laboratory studies Newell R. Murphy, Allan S. Lessem, and Windell F. Ingram developed pertinent mathematical equations, while Richard B. Ahlvin of the Data Handling Branch was largely responsible for computer programming.40

Acceptance of the Army Mobility Model extended beyond the United States. In 1978 NATO adopted AMM-75 and its subsequent refinements for use in Europe. The now internationally sanctioned program was known as the NATO Reference Mobility Model (NRMM).

Computer Mapping of Tactical Areas

Practical application of AMM-75 and its successors depended upon the availability of accurate computer maps, particularly for areas where military operations were likely to take place. In early efforts, dating to the 1950s, WES specialists had manually prepared maps for mobility evaluation purposes. Using air photos, existing roadmaps, topographical maps, soil surveys, and other observations for sources, technicians prepared single-factor maps, then overlaid them to produce factor family maps. This required skilled map and airphoto interpreters who understood vehicle mobility fundamentals. The process was slow and costly, and the maps produced did not lend themselves well to computer manipulation.

The AMC and AMM projects revised and updated map-making methods to use computers extensively, from development of single-factor terrain unit maps through the production of comprehensive mobility maps. Maps produced for AMC-71 field validation tests furnished early models for small areas at the five study sites on U.S. military reservations. Technicians had also mapped a few further "transects" relatively long and narrow strips in West Germany, Thailand, Puerto Rico, and South Korea in conjunction with early AMM-75 studies. Thus, even as the mobility model found acceptance in the military community, computer mapping of tactical areas remained almost non-existent.41

Thumbnail for Landsat photo Thumbnail for Contour map following digitization Thumbnail for Contour map prior to digitizationThe dearth of areal maps stimulated a long-term effort at WES and other locations, such as the U.S. Army Engineer Topographic Laboratories and Defense Mapping Agency, to chart tactical areas for computerized mobility predictions. That effort continues into the 1990s. Civilian authorities also saw the advantages of computer mapping to detect things such as the extent of flooding, forest and agricultural land-use patterns, and many other phenomena.

In 1972 areal mapping agencies acquired a revolutionary new tool: orbiting satellites. Two Landsat models circled the globe every 103 minutes, providing high-resolution, timely photographic images of vast areas. Still in its formative state, however, satellite photography required verification, refinement, and development of methods for computerization. Studies by James G. Kennedy and Albert N. Williamson provided techniques for digitally overlaying Landsat scenes of an area, detecting changes that occurred during intervals between scenes, and displaying results on tactical maps. WES work also spawned methods for converting Landsat computer-compatible tapes to images on photographic film.42

A noteworthy study by Horton Struve, Grabau, and Harold W. West involved detailed mapping and study of an area north of Vicksburg. Several different terrain types characterized the site, including agricultural lands (plowed fields, fields with crops at different stages of growth, and fallow land), forested land with mixed deciduous and evergreen trees, grasslands, water features, and other elements. Because the area was well documented by observation, topographical maps, and aerial photos, known quantitative factors could be compared with impressions derived from Landsat photos. This contributed to more accurate interpretation of satellite photos, especially concerning the influence of shadows and variations in coloration of terrain due to seasonal changes.43

Continuation of Field Tests

Field tests through the 1970s and into the 1980s continued to supplement and refine mobility projections. In 1977 and 1978 WES personnel participated in mobility studies in the Fulda Gap area of West Germany, while two related projects evaluated performance of a wide variety of cargo trucks, fuel transporters, wreckers, and other tactical transport vehicles being considered for adoption by the Army. Using the Army Mobility Model to predict performance of candidate vehicles in the study area in terms of speed profiles for dry, wet, and snow surface conditions of the primary roads, secondary roads, and off-road tracts, project coordinators compared computer predictions with actual field performance.44

More studies performed stateside involved combat vehicles. In 1975, as part of the XM1 tank development program, Barton G. Schreiner of the Mobility Investigations Branch supervised tests at the Aberdeen Proving Ground, Maryland. These involved determination of ride, shock, and mobility performances of competing XM-1 prototypes developed by Chrysler and General Motors corporations. For comparisons, trials also included a German LEOPARD II tank, a standard M60, and four M60 series tanks with improved suspensions. Quantification of observations further enabled Army planners to incorporate projected tank performance into the AMM and to adopt and adapt vehicles based on specific known criteria.45 Both the Fulda Gap and stateside projects enabled Army mobility specialists to select and modify vehicles based on specific known quantified data.

A concurrent series of field tests, concluding in 1976, dealt with the effectiveness of craters and associated ejecta as barriers to mobility. The first, Event Dial Pack, conducted in 1970 in Alberta, Canada, involved detonation of a 500-ton TNT charge, then analysis of mobility performance of a M37 3/4-ton cargo carrier and a M113A1 armored personnel carrier in traversing the resulting crater and surrounding area.46 Later related projects Diamond Ore, Event Mixed Company, Essex I, and Dice Throw subjected more vehicles, including tanks, to crater conditions in different soil and rock media at a variety of locations. Data furnished further input to AMC-71 and AMM.47

Non-Military Environmental Activities

Thumbnail for Barge-mounted laser gun used in waterhyacinth control effortsIn the late 1960s, some Mobility and Environmental Division staff members became involved in studies unrelated to military activities. In an unanticipated assignment, WES took the lead in the fight against the ubiquitous waterhyacinth. Originally introduced into the United States in the late 1800s from South America, by the 1930s it had become the scourge of southern waterways. Conventional methods of control dredging, dynamite, or chemicals were ineffective or dangerous to the environment. In 1968 researchers at Redstone Arsenal in Huntsville, Alabama, discovered that infrared light with a wavelength of 10.6 micrometers seemed to reduce propagation and growth of the plants. OCE then assigned WES the task of devising a prototype laser system that could be used in the field. Shockley's engineers designed a barge facility replete with a laser gun that produced about 4,000 watts of infrared radiation concentrated in a 0.5-inch beam. A mirror system spread the beam and directed it at the floating plants.48

Although the laser control system ultimately proved useless, the Mobility and Environmental Division (MESL after 1972) became increasingly active in "environmental" studies in their traditional civilian definition. In 1972 Shockley initiated a major Aquatic Plant Control Research Program for OCE that involved use of herbicides, lasers, insects, pathogens, and plant-eating fish in the struggle to manage troublesome aquatic flora.49 MESL activities reflected the increased interest in a broad range of environmental issues nationally and the Corps' enlarged role in environmental research. This in 1974 resulted in the establishment at WES of a separate Environmental Effects Laboratory that expanded civil research into areas other than aquatic plant control.

Mobility Returns to the Soils Laboratory

As interest in non-military environmental research intensified and the war in Southeast Asia ended, funding for mobility research declined precipitously. WES administrators by the late 1970s questioned the viability of maintaining mobility and military environmental studies in a separate organizational context. In a major reorganization, in 1978 the Mobility and Environmental Systems Laboratory merged back into the Soils and Pavements Laboratory. Dropping the now-confusing "environmental" appellation, it became the Mobility Systems Division. WES then renamed the entire soils-pavementsmobility entity as the Geotechnical Laboratory (GL). In adopting the more inclusive term "geotechnical," WES followed the lead of the ASCE, which in 1974 had changed the name of its Soil Mechanics and Foundations Division to the more apt Geotechnical Engineering Division.49 The Environmental Effects Laboratory, renamed the Environmental Laboratory, assumed all non-military environmental research, including the aquatic plant control efforts previously conducted by MESL. The Mobility Systems Division, Geotechnical Laboratory, then returned to its original mission, which was almost exclusively military.

Conclusion

Activities of the Mobility and Environmental Systems Division in the 1960s and through the 1970s ranged from the jungles of Southeast Asia to the surface of the moon. In the broad MERS study in Thailand, WES developed trafficability, mobility, and environmental classifications which U.S. strategists used in the similar terrain of Vietnam. As part of the massive American program to land men on the moon, WES played an integral role in developing the mobility system for the lunar roving vehicle. By the 1970s, computerization brought new capabilities to mobility studies. WES developed the Army's first comprehensive computer mobility model, AMC-71, which enabled military planners to predict vehicle performance in computer-mapped areas around the world. Continued refinement led to production of the AMM-75 computer model, which NATO adopted as its standard.