SAC architecture for the 2018 Mars Sample Return mission

Reducing the mission risk was our primary driver in developing the Sample Acquisition and Caching (SAC) architecture. In particular, the main goal was to reduce number of steps from the moment the core is acquired to a point where it is inserted into the earth return cache. The proposed architecture consists of three elements: (1) a rotary percussive drill with integrated core break-off and retention system, (2) a 5-DOF robotic arm for positioning of the drill on a rock, and (3) a bit carousel with an earth return cache. The drill acquires and retains 1 cm diameter and 5 cm long cores. The core, together with a drill bit, is then inserted into an Earth return cache or a bit storage carousel. A new drill bit is attached to the drill for acquisition of the next rock core. Once the cache is full, the arm places the cache on the ground, to be later picked up by a fetch rover. The same drill also uses custom drill bits for brushing and abrading of rock surfaces, for rock powder acquisition and for acquisition of short cores for in-situ analysis. These bits are used for rock interrogation prior to acquisition of cores for sample return. After the cache is placed on the ground and primary mission is over, these bits enable further exploration of the Martian near subsurface.