| Popis: |
The Comet Astrobiology Exploration Sample Return (CAESAR) mission will acquire and return to Earth for laboratory analysis a minimum of 80 g of surface material from the nucleus of comet 67P/Churyumov-Gerasimenko (67P). CAESAR will characterize the surface region sampled, return the collected solid sample in a pristine state, and return evolved volatiles by capturing them in a separate gas reservoir. A key to mission success is to select a sample site that provides high science value, and that is fully compatible with safe and successful sampling. Key supporting objectives are to characterize the sample site and its geophysical and geomorphic context, and to study the comet environment to identify spacecraft hazards including moonlets, jets and plumes. These mission objectives drive a number of key imaging requirements that in turn drive camera designs and calibration: detecting 50-cm objects from 500 km; resolving 2.5-cm particles from 650 m; obtaining 5° and 30° field of view optical navigation images; identifying 1-cm particles from 50 m; imaging at multiple colors, matching a subset of the Rosetta OSIRIS filter bandpasses; documenting the sample site before, during, and after sampling at sub-cm resolution; and documenting sample acquisition during sampling and packaging inside the return capsule. In order to accomplish these goals, CAESAR carries a high-heritage suite of six well-calibrated cameras of varying fields of view and focal ranges: narrow angle camera (NAC), medium angle camera (MAC), touch-and- go camera (TAGCAM), two navigation cameras (NAVCAMs), and a sample container camera (CANCAM). |
