Encyclopedia Astronautica
Pressurized Lunar Rover - Dual Hull



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Pressurized Rover
Pressurized Lunar Rover - Dual Hull
American manned lunar rover. Study 1992. An alternate April 1992 USRA study by students at Virginia Polytechnic Institute and State University sketched out a design for a Pressurized Lunar Rover (PLR) using dual hulls.

Under a contract from NASA, in the late 1980's and early 1990's the Universities Space Research Association (USRA) operated the NASA/USRA University Advanced Design Program. Several participants in the Advanced Design Program chose as their project a pressurized rover for Moon or Mars exploration. An April 1992 report by students at Virginia Polytechnic Institute and State University covered the "Design of a Pressurized Lunar Rover." This concept had two cylindrical pressure hulls passively connected by a pressurized flexible passageway. The dual system concept allowed a combination of articulated motion and double Ackerman steering for executing turns. Their design had a total length of 11 m total length with two 5 m length cylinders that were 4 m in diameter. Total weight was 7,000 kg. The pressure vessel consisted of inner and outer graphite/epoxy shells with NOMEX honeycomb core and a Kevlar micrometeoroid shielding. The two wheels on the side of each body were attached to a common structural bar that was pinned to the vehicle in the center. This allowed maximum wheel contact in rough terrain. A dynamic isotope power system in conjunction with a closed Brayton cycle generator supplied a constant power of 8.5 kw. Excess heat was dissipated through thermal radiators. Four 2 m diameter wheels were used on each body. An independent brushless DC motor powered each wheel through a 50:1 speed reduction planetary traction drive. The dual vehicle concept with independent propulsion at each wheel allowed an articulated motion for ease of propulsion through loose soil. Nominal speed was 14.7 km/hr and top speed was 29.4 km/hr. The rover supported a nominal crew of four for 14 days, and was able to support a crew of six in an emergency with no range requirement Nominal range was 2000 km, and the rover could negotiate a maximum grade of 26.5 percent, and a maximum crossable crevice of 1.7 m.

PLR Summary

Primary dimensions:

  • Total vehicle length: 11 m
  • Cylinder length: 5 m
  • Cylinder diameter: 4 m
  • Flexible passage length: 1 m
  • Wheel diameter: 2 m
  • Wheelbase: 7.5 m

Equipment Summary

  • Primary power source: Dynamic Isotope Power System (closed Brayton cycle)
  • Secondary power source: Sodium-sulfur batteries with photovoltaic array
  • External fixtures:
  • 1 x 1.2 meter parabolic reflector antenna
  • 1 x omnidirectional VHF antenna
  • 6 x exterior storage bins and tool boxes
  • 4 x visibility and maintenance cameras with lights
  • 4 x driving lights
  • 2 x robotic arms
  • 1 x scientific airlock
  • 2 x crew airlocks
  • 1 x towing hitch
  • 1 x docking fixture
  • 2 x EVA seats
  • 1 x high resolution landscape camera
  • 1 x 9 m2 directable solar collector array
  • 2 x 7.5 m2 directable thermal radiators
  • 4 x second surface mirror radiators

Mass Breakdown:

  • Structure and Pressure Vessel: 553 kg
  • Inner Graphite/Epoxy Shell: 84 kg
  • NOMEX Core (Honeycomb): 559 kg
  • Outer Graphite/Epoxy Shell: 130 kg
  • Elastomer Layer (for Thermal Mismatch): 378 kg
  • Aluminum Coating: 238 kg
  • Flexible Connection: 652 kg
  • Saddle: 240 kg
  • KEVLAR 29 Micrometeoroid Shielding: kg
  • Thermal Control System: kg
  • Insulation: 130 kg
  • Radiator: 90 kg
  • Pumps: 20 kg
  • Heat Exchanger: 50 kg
  • Piping: 100 kg
  • Refrigerant: 50 kg
  • Power system: kg
  • Engines: 200 kg
  • Structure: 60 kg
  • Heat Source Blocks: 200 kg
  • Radiation & Housing: 500 kg
  • Power Distribution: 40 kg
  • Sodium Sulfur Batteries: 16 kg
  • Solar Collectors: 18 kg
  • Mobility: kg
  • Tires (8): 240 kg
  • Motors (9): 36 kg
  • Gearing Sets (9): 36 kg
  • Suspension Groups (4): 60 kg
  • Steering: kg
  • Articulated Frame Joint & Connection: 50 kg
  • Environmental Control/Life Support: kg
  • Atmospheric Control & Supply: 80 kg
  • Atmospheric Revitalization: 20 kg
  • Fire Detection & Suppression: 10 kg
  • Water Recovery & Management: 120 kg
  • Waste Management: 20 kg
  • Extra-vehicular Activity & Support: 20 kg
  • Crew airlocks: 230 kg
  • Internal Facilities: kg
  • Communications: 25 kg
  • Guidance and Navigation: 10 kg
  • Galley: 70 kg
  • Personal Hygiene: 90 kg
  • Emergency Equipment: 30 kg
  • Drive Stations: 80 kg
  • Work Stations: 40 kg
  • Sleep Quarters: 60 kg
  • External Fixtures: kg
  • Visibility & Maintenance Cameras (2): 8 kg
  • High Resolution Landscape Camera: 4 kg
  • Lights: 4 kg
  • Antenna: 15 kg
  • Telerobotics: 22 kg
  • Drill Coring: 10 kg
  • Winch: 5 kg
  • Hitch: 2 kg
  • EVA Suits: 450 kg
  • Crew: 360 kg
  • Payload: 500 kg
  • TOTAL MASS: 7015 kg

Performance:

  • Maximum Velocity: (4 wheels), 14.7 km/hr
  • Maximum Velocity: (8 wheels), 29.4 km/hr
  • Nominal Power Requirement: (4 wheels) 1.36 kW/wheel
  • Nominal Power Requirement: (8 wheels) 0.68 kW/wheel
  • Maximum Allowable Power: 1.5 kW/wheel
  • Maximum Gross Pull: 900 N/wheel
  • Maximum Vehicle Acceleration: 0.64 m/s^2
  • Soil Compaction Resistance:
    • Normal Soil: 22 N/wheel
    • Soft Soil: 81 N/wheel
    • Hard Soil: 4.0 N/wheel
  • Minimum Turn Radius (in percent of vehicle length):
    • Neutral Steer: 78.3%
    • Oversteer: 60%
  • Range: 2,000 km
  • Maximum Gradient: 26.5 degrees
  • Wheel Sinkage:
    • Normal Soil: 1.03cm
    • Soft Soil: 2.86 cm
    • Hard Soil: 0.21 cm
  • Climbable Step Height: 0.53 m
  • Crossable Crevice: 1.7 m

  • System Power Required:
  • Drive Motors
    • Normal Operations 5,452 W
    • Maximum 12,000 W
  • ECLSS 160 W
  • Operation (computers, communication, etc.) 600 W
  • Thermal Control:
    • Average 800 W
    • Maximum 1,356 W
  • Internal Requirements (includes lights, galley, hygiene, etc.): 1,500 W
  • External Lighting 1,000 W
  • Experiments 1,000 W
  • Miscellaneous 1,000 W

    Crew Size: 4. Electric System: 8.50 average kW.

    Gross mass: 7,000 kg (15,400 lb).
    Height: 11.00 m (36.00 ft).
    Diameter: 4.00 m (13.10 ft).

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    Associated Countries
    See also
    • Lunar Rovers Lunar rovers were studied in a dizzying variety of sizes and shapes by NASA in the 1960's - including crawlers, trains, hoppers, and even worms. Two rovers designed for manned use actually traveled the lunar surface in the 1970's - the American two-man Lunar Rover, and the Soviet Lunokhod, which traveled the moon in robotic mode but was originally designed as emergency cosmonaut transportation. More...

    Associated Manufacturers and Agencies
    • NASA American agency overseeing development of rockets and spacecraft. National Aeronautics and Space Administration, USA, USA. More...
    • Virginia American manufacturer of spacecraft. Virginia Polytechnic, USA. More...

    Bibliography
    • Zakrajsek, James J; McKissock, David B; Woytach, Jeffrey M; Zakrajsek, June F; Oswald, Fred B; McEntire, Kelly J; Hill, Gerald M; Abel, P; Exploration Rover Concepts and Development Challenges, NASA/TM-2005-213555 / AIAA-2005-2525, March 2005.
    • Bhardwaj, Manoj; Bulsara, Vatsal; Kokan, David; Shariff, Shaun; Svarverud, Eric; and Wirz, Richard, Design of a Pressurized Lunar Rover, NASA-CR-192033, 24 April 1992.

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