scope:

Abstract:

The Mariner '69 Scan Platform and the Viking Orbiter Imaging Instrument Filter Wheel were operated with relative position stepping commands. In both cases, anomalies caused actual position to become different than the desired position. (This lesson largely duplicates #0405) Provide an explicit or absolute positioning capability in which the device can be commanded to a specific position, allowing development of sequences in which periodic positioning to absolute locations can be executed. (This recommendation largely duplicates #0405 (D))