Abstract

Ambitious objectives for the NASA/ESA Cassini orbiter/Titan probe mission to the saturnian system include the determination of composition and distribution of material within rings, on satellite surfaces, and within the atmospheres of Saturn and Titan. Dynamic processes which lead to spatial and temporal variations are also to be investigated. Known materials include hydrogen, methane, ammonia, phosphine, germane, and carbon monoxide for Saturn; nitrogen, methane, and higher hydrocarbons for Titan; and water and possibly ammonia ice for the other satellites and rings. Within atmospheres, ammonia (for Saturn) and methane (for Titan) are suspected condensates. Such an assortment of materials in a diverse set of planetary objects calls for versatile yet low power, low mass instrumentation. Polarimetric imagers enable investigations of ices in atmospheres, rings, and satellite surfaces. Acoustooptic tunable filters (AOTFs) specifically enable rapid, high signal-to-noise simultaneous acquisition of orthogonally polarized images in arbitrary spectral bands. Spectral mappers enable the assessment of trace gases within planetary atmospheres. Specifically, digital array scanned interferometers (DASIs) address desired high and low resolution, wide spectral band observations at high throughput, efficiency, and spectral fidelity. AOTFs and DASIs are compact, no moving parts, electronically spectrally adaptive instruments well suited for analyses of material within the saturnian system.

© 1989 Optical Society of America