Mars hand lens imager: Lens mechanical design

In 2011 NASA will launch the Mars Science Laboratory (MSL) as part of its Mars Exploration Program to learn more about the red planet´s environment and geological history. To fulfill that goal, the MSL rover, built by NASA´s Jet Propulsion Laboratory (JPL), is outfitted with the most extensive array of scientific instruments ever landed on the Martian surface. The Mars Hand Lens Imager (MAHLI), mounted on the end of the rover´s robotic arm, is one of the primary science cameras for MSL. This camera affords many improvements over those used on previous Mars missions, particularly the ability to focus throughout a wide spatial range. A novel mechanism uses one motor to actuate an internal lens group, enabling focus capability, and manipulate a protective dust cover. This mechanism is designed to operate in the severe thermal environment of the MSL mission (-120deg C to +40deg C) and to survive for one Martian year with 3x margin (about 2000 Earth days) using non-standard materials and techniques in order to meet mass and optical requirements. Several issues involving lubrication and wear were encountered in developing this instrument; each solved through sound engineering and/or system level redesign. The qualification model passed full level life testing at temperatures throughout the operating range with negligible reduction in performance. Alliance Spacesystems, LLC supplied the flight model mechanism to Malin Space Science Systems (MSSS) where it was integrated with electronics and in turn delivered to JPL in October 2008.