More Questions than Answers?
I write this with just a few months remaining before the end of the MESSENGER mission. The low altitude campaign has yet to bear its full fruits. These will include a wealth of NAC images at better than 10 m per pixel, some oblique upward UVVS scans from deep within the exosphere to study spatial enhancements of Ca and Mg, and a targeted search by GRNS for iron and carbon in areas surfaced by low reflectance material. Low altitude passages will also allow spatially smaller, and shallower, contributions to the gravitational field to be resolved, which may offer insights into the heterogeneity and/or thickness of the crust.