Major Concerns ●Lunar conditions ○Extreme temperatures ○Radiation ○Solar wind ○Large jagged rocks that create point loads ●Regolith ○The moon’s dust (regolith) is electrostatically charged and very abrasive ○Clogs wheel components ●Traction ○Slippage across an incline ○Slippage traveling up an incline
Introduction ●Improvements upon last year’s wheel ○Replace welds with aerospace adhesives ○Handle point loads better ○Improve traction
Methods: Design ●Lack of exact vehicle constraints ○Main focus of design concept is based on the lunar environment constraints ●Regolith and various sizes of meteor fragments ○Large fragments cause extreme point loads ■Outer surface of the wheel needs to be flexible and durable ■Elastic outer rim layer that will deflect and distribute point load ■Design needs to be as open as possible to allow regolith resistance
Methods: Materials ●Solution to clogging and coating of lunar regolith ○NASA and n-gmat, a nano-materials company has produced a coating ■Made from the lotus flower that has self- cleaning properties ●Possible use of adhesive in place of rivets ○Masterbond Supreme 10HT adhesive has a temperature range of -269 to 204 degrees Celsius ■NASA approved for low outgassing
Material Selection ●6xxx series alloys ○contain magnesium and silicon and these alloys have a good balance of corrosion resistance and strength ●Examined Aluminum 6061 T6, 6063 T6,and 6066 T6 ○evaluated strength, corrosion resistance, malleability, cost, and operation temperature tolerances ●Aluminum alloy 6061 T6 ○reasonable yield strength, relative low cost, and good corrosion resistance
Monarch Wheel Mark III ●Outer Layer ○An offset pattern of kidney shaped springs form a layer meant to absorb large point loads. ●Inner Layer ○A series of five spring loaded hinged spokes for a larger scale deflection, such as that from a large rock, allowing the tread to contact more surface
Traction ●Gecko tread ○Independent spring mounted treads ■improve traction and the wheels handling of point loads ■rhombus shape gives lateral and longitudinal grip
Methods: Testing ●Impact testing ○Impact testing on scaled models ○“Real-world” testing of prototypes ■Wheels mounted on to a pickup truck and driven over various surfaces simulating those of the moon ●Compression testing ○Point load testing of vehicle components ■placed between two conical steel platforms and compressed until failure occurs ○Spring testing ■tested and evaluated so as to relate the springs linear k value to torsional and bending k values
Methods: Testing ●Traction testing ○Lateral and longitudinal slip conditions ○Control and slip tests will be conducted using scaled replicas at 1/5th scale of the designs over three surfaces ■ a regolith simulant, a rocky surface, and a mixture of the two ○The tread pattern will be tested using a remote control vehicle ○A dynamometer will be used to measure torque required for slip
Bibliography D. V. Margiotta, W. C. Peters, S. A. Straka, M. Rodriguez, K. R. McKittrick, and C. B. Jones, "The Lotus coating for space exploration - a dust mitigation tool," in Optical System Contamination: Effects, Measurements, and Control 2010, 2-5 Aug. 2010, USA, 2010, p. 77940I (7 pp.). D. Cao, A. Khajepour, and X. Song, "Modeling generalization and power dissipation of flexible-wheel suspension concept for planetary surface vehicles," Vehicle System Dynamics, vol. 49, pp. 1299- 1320, 2011/08/01 2011. M.Abdel-rahman, A.Ahmed, E.Badawi, “Testing Natural Aging Effect on Properties of 6066 & 6063 Alloys using Vickers Hardness and Positron Annihilation Lifetime Techniques,” Defect and Diffusion Forum, Vol. 303- 304, no., 107-112, Jul 13, 2010.
Your consent to our cookies if you continue to use this website.