Mars Science Laboratory ChemCam Sun Safety

The Mars Science Laboratory (MSL) ChemCam instrument can be damaged when the Sun enters or passes through its field of view (FOV). There is no Sun cover, yet other instruments mounted with boresights pointing in the same direction must observe the Sun for scientific observations and for attitude determination. When in a Suntolerant focus range during rover motion and pointing for observations by other remote sensing instruments, the Sun must be allowed to pass through the ChemCam FOV, and when in a Sun-damage focus range for ChemCam observations, the Sun must never be allowed to enter the FOV, even after a rover system fault. Both of these scenarios depend upon knowledge of the attitude of the rover relative to the motion of the Sun. A Sun search that is guaranteed to be Sun-safe for the ChemCam, even when the location of the Sun is unknown, had to be developed.