MERLIN: MARS-MOON EXPLORATION, RECONNAISSANCE AND LANDED INVESTIGATION

摘要

Mars' moons Phobos and Deimos are low-albedo, D-type bodies. Their compositions and origins are unknown:they have been proposed to consist of highly space-weathered material like that forming bulk Mars or Mars's crust,or alternatively primitive carbonaceous material possibly like that which contributed organics and volatiles to theaccreting terrestrial planets. A Discovery-class mission concept, the Mars-Moon Exploration, Reconnaissance andLanded Investigation (MERLIN), will investigate one of Mars' moons scientifically using in situ measurements totest models for the moon's origin. The nominal target is Deimos, but MERLIN could also investigate Phobos instead.The scientific measurement objectives of MERLIN are to determine Deimos' elemental and mineralogicalcomposition, to investigate its volatile and organic content, and to characterize processes that have modified itssurface. These same measurements characterize physical properties of the surface and the moon's environment,providing valuable precursor information preparatory to future human exploration. To achieve MERLIN's objectives,a landed payload will obtain stereo imaging and measurements of elemental and mineralogical composition andinterior structure. An orbital payload will acquire global high-resolution and color imaging, putting the landing sitein context by characterizing Deimos' geology. Following MOI the spacecraft flies in formation with Deimos, anduses small changes in its orbit around Mars to investigate Deimos from a range of altitudes and illuminations over 4months. Data taken during 1- to 2- km altitude flyovers will certify a landing site. The spacecraft will be delivered toa point several km above Deimos, and will navigate to landing on a fresh exposure of regolith using onboardimaging. A 90-day baseline landed operations period will provide a complete set of landed measurements from asingle location.