41. The mass of the structure and aluminum alloy shell was about 30 kg and the propulsion units roughly 90 kg. 42. The U . S . Air Force had overall project control but the Navy gave vital help with propulsion units . 43. The concept of a planetary propulsion unit on the surface of Mondas was derived from " Attack of the Cybermen ". 44. When not in use, the propulsion unit water intakes are closed off with armoured covers to prevent damage during digging operations. 45. The Cyberplanner, though, is insisting that the power necessary to operate the propulsion unit must be directed into processing the population. 46. The stern propulsion units are rated at 6.5megawatts each while the azimuth thruster in the bow has propulsion power of 6megawatts. 47. Siemens stated that this will allow a reduction in the number of propulsion units per train, while still maintaining train performance. 48. The cargo ship had brought several tons of supplies, including a new propulsion unit that the crew put assembled last month. 49. When the crew later attempted to back the Barberi out of the terminal using these local controls, both propulsion units functioned normally. 50. There was also a version of the T360 called the " Snow Crawler ", equipped with tracked propulsion units at the rear.