Sol 39 through 41 (Sept. 14 - 17) were driving days for the Curiosity rover. On Sol 39, Curiosity logged 72 feet (22 meters) driven. On Sol 40, the rover drove another 121 feet (37 meters). On Sol 41, Curiosity logged 89 feet (27 meters), across the surface of Gale Crater. During this sol, for the first time, the DAN instrument (the Dynamic Albedo of Neutrons investigation) was incorporated into the rover's drive sequence. In its active mode, DAN can detect minerals associated with water below the surface. Along Curiosity's path, DAN shoots neutrons into the ground and measures how they scatter. The instrument has a high sensitivity for finding any hydrogen to a depth of about 20 inches (50 centimeters) directly beneath the rover. After driving 33 feet (10 meters), the rover stops and the DAN instrument operates for two minutes. Then another 10 meters, then another DAN measurement.
Total distance racked up by Curiosity since landing on Mars on Aug. 5 is 745 feet (227 meters).
An image of the surface of Gale Crater, taken on Sol 41 by the rover's left navigation camera, is available at: http://1.usa.gov/OAG8Rv .
Curiosity continues to be in good health. Sol 41, in Mars local mean solar time at Gale Crater, ended at 10:33 a.m. Sept. 17, PDT.