ROBOTIC ARM FOR FIBER-OPTIC COUPLING MANIPULATION IN VACUUM

Abstract

The Lunar and Planetary Laboratory (LPL) is interested in non-invasive spectral bidirectional reflectance distribution function (BRDF) measurement methods of asteroid samples. This engineering project developed a vacuum compatible autonomous fiber-optic cable exchanging system. The project also developed a custom fiber-optic passthrough to allow for signal exchange between the vacuum and external spectrometers. A mechanical fiber-caddying system allowed for autonomous interchanging between data-collection fibers. A pin retention system secured a fiber upon selection. The SMA905 fiber ending had an adapter designed so it could work with the pin retention system and the caddying system. Tests in the retention system ensured the proper choice of spring stiffness so any servo motor could exchange fibers between the caddy system. A custom CF flange containing fiber-connection points and epoxy-sealed windows was designed to maintain the vacuum seal and allow for light transfer out of the vacuum to external spectrometers. Tests were performed on the designed and fabricated CF flange with connected industry fibers to ensure the transmittance yielded viable spectral recovery. Overall, the designed fiber adapter, pin retention system, and caddy system allowed for repeatable autonomous fiber interchange. The CF flange maintained the vacuum seal while transmitting sufficient spectral power to external spectrometers.