Answer Happy

DATA TABLE Acceleration due to gravity on the Moon (gmoon) = 1.62 m/s2 Young's modulus for Al (E) = 71 GPa Young's modulus for Ti (E)= 110 GPa Young's modulus for soil (E) = 0.6 MPa Density of Al = 2710 kg/m3 Density of Ti = 4510 kg/m3 Poisson's ratio for engineering materials v=0.35 Poisson's ratio for soils v=0.3 Lunar regolith density, p = 1500 kg/m3 Lunar regolith friction angle o =40° Lunar regolith cohesion c= 0.5 kN/m2 Lunar regolith modulus of cohesion of soil deformation kc = 1.4 x 103 N/m² Lunar regolith modulus of friction of soil deformation ko = 8.2 x 105 N/m3 = = =
NASA's ATHLETE (all-terrain hex-limbed extraterrestrial explorer) lunar rover chassis comprises six wheels each mounted onto an articulated leg. Each of its six wheels has a diameter of 0.71 m and width of 0.2 m. The articulated legs allow the rover to step over obstacles up to 1.5 m in height above the lunar surface. The mass of the chassis itself is 850 kg. It carries a 2.34 m diameter by 3.66 m long habitat module which fully laden masses at 15 metric tonnes, i.e. total rover mass of 15.85 tonnes on the Moon. 1. The system is modular so two elastic mobility system tracks can replace the six wheels. The two continuous tracks each have a ground contact length of 3.66 m by 0.2 m width. Assuming that the track curvature has the same diameter as the wheels (0.71 m), calculate the mass of the track required to support the lunar habitat module if the elastic loop is constructed from aluminium and titanium respectively. (10 marks)