Image-Based Focus Retention Verification of a Commercial Optical Microscope Module in Launch Environments

Recent growth in space biomedicine has increased the need for compact optical microscope modules for biological observation under microgravity. In this study, two nominally identical commercial off-the-shelf (COTS) microscope units were evaluated under launch vibration and shock environments. One unit was mounted with a laminated viscoelastic passive vibration isolator, while the other was mounted without isolation. Random vibration and shock tests were performed to evaluate structural characteristics and focus retention. During random vibration, the non-isolated configuration showed high acceleration responses and clear focus degradation. In contrast, the isolated configuration reduced the overall acceleration response by up to 3.96 times and maintained a focus retention ratio above the study-specific screening threshold of 0.8. LLSS results and visual inspection showed no clear change in global structural characteristics or visible damage. After shock testing, both configurations remained above the same threshold with no marked focus degradation. Under the applied test conditions, broadband random vibration caused greater focus degradation than short-duration shock loading. These results indicate that image-based focus retention assessment should complement structural assessment when verifying COTS optical microscope modules for space biomedical applications.