Precision motion control and nano-positioning industry leader, PI, plays a key role in distance targeting of geological samples for testing by the Mars rover, Perseverance.
Perseverance rover image courtesy of NASA/JPL
Exacting control of the optical focus is required by the space-qualified variant of the PI miCos MT Series stepper-motor stage as it axially translates the secondary mirror of the telescope which collects the optical return from the sample while providing imaging information to place the sample within geologic context. This is the second time PI precision motion equipment has traveled the long distance to our neighboring planet. The rover, Curiosity, has relied on PI’s patented PICMA® piezoelectric transducers and an another motorized focusing stage since first landing in 2012.
The shocks and vibrations of launch and landing necessitated that every component in the customized stage, from the stepper motor to the crossed roller bearings, be validated and optimized to eliminate the possibility of failure or degradation. The autofocus process places stringent demands on the stage’s performance – resolution, backlash, trajectory quality, and stability are all crucial for responsive operation and reliable data.
The wide temperature excursions to which the stage was to be exposed in flight and on the Martian surface added significantly to the challenge. Modeling and thermal compensation technologies and sophisticated vacuum-compatible components, coatings, and lubricants were utilized. This specialized variant of the commercial-off-the-shelf (COTS) stage passed all preflight tests and validated the cost-containment strategy of leveraging COTS designs.
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