Mobility Study For A Lunar Rover

ABSTRACT One of the human exploration initiatives being explored by the National Aeronautics and SpaceAdministration (NASA) involves a program that would build on and extend the legacy of the Apollo programthrough scientific research and exploration. The construction and operation of a very low frequency radioastronomy observatory on the far side of the Moon is one of the many scientific endeavors being consideredthat would require a robotic lunar surface vehicle system. A supervisory controlled rover vehicle has beenconceptually defined to support the construction of this large array in the 2000 to 2010 time frame. Thispaper describes the observatory, briefly discusses the vehicle design /operational requirements, identifieskey system /subsystem options and trades, and presents the vehicle concept developed. Particular emphasis isplaced on vehicle mobility system considerations.1. INTRODUCTIONThe astronomical community currently is studying the scientific basis and design aspects associated with avery low frequency array (VLFA) placed on the far side of the Moon for radio astronomy observations.1 Thispaper presents the results of a study that supported these efforts by exploring robotic techniques that wouldfacilitate the emplacement and assembly of array elements in the 2000 to 2010 time frame. In particular, theobjective of this study was to conceptually define a robotic vehicle system to support the construction of aVLFA on the lunar surface.2. THE VERY LOW FREQUENCY RADIO ARRAYOne of many proposed lunar astronomical facility concepts, the VLFA would be built in a crater on thelunar far side. The array would operate in the 1 to 30 MHz frequency range to explore the long- wavelengthradio sky. The array would increase in size (from 17 to 1000 km in diameter) over its lifetime.At its initial operational capability, one concept for the VLFA would consist of dipole antenna elementsemplaced in a two -turn spiral configuration within a 17 -km diameter? Placement of the array elements wouldbegin in a central location and proceed outward with the dipoles placed in a continuous spiral pattern.Spacing between dipoles would increase with radius. As currently envisioned, the initial 17 -km diameterregion would consist of approximately 300 antenna elements, each unit of which would include a dipoleantenna, electronics package, power source, and data transmission link to a central data processing facility.The remainder of the crater would then be configured similarly with 300 additional antenna elementslocated along a two -turn extension to the spiral pattern. The eventual goal, after filling the crater, is tocontinue placing elements beyond the crater boundaries. This likely would be done by hard -landing individualunits on the surface beyond the crater, since rover travel would be prohibitive.3. VEHICLE DESIGN /OPERATIONAL REQUIREMENTSThe design of the vehicle was constrained by several factors, including initially prescribed groundrules; mission, system operational, and functional requirements; and the lunar environment. This sectionsummarizes the design and operational requirements necessary to support the preliminary system design.Those requirements that specifically affect the vehicle mobility system are outlined here; detailed require-ments have been documented in a separate report.3