The Venus Emissivity Mapper (VEM) - Obtaining Global Mineralogy of Venus from Orbit

Abstract

The Venus Emissivity Mapper is the first flight instrument designed to focus on mapping the surface of Venus using atmospheric windows around 1 micron. After several years of development, VEM has a mature design with an existing laboratory prototype verifying an achievable instrument SNR of well above 1000, as well as predicted error in retrieval of relative emissivity of better than 1%, assuming the availability of an improved Venus topography. It will provide a global map of rock type, iron contents and redox state of the surface by observing the surface with six narrow band filters, ranging from 0.86 to 1.18 micron. Three additional windows allow corrections for cloud composition and variability, two measure water abundance, and three compensate for stray light. Continuous observation of Venus' thermal emission will also place tighter constraints on current day volcanic activity. Eight of the channels provide measurements of atmospheric water vapor abundance as well as cloud microphysics and dynamics and permit accurate correction of atmospheric interference on the surface data. Combining VEM with a high-resolution radar mapper, such as on the ESA EnVision or NASA VERITAS mission proposals, will provide key insights into the divergent evolution of Venus and Earth.