Ganymede (moon) Ganymede. The most recent close observations of Ganymede were made by "New Horizons", which recorded topographic and compositional mapping data of Europa and Ganymede during its flyby of Jupiter in 2007 en route to Pluto. The Europa Jupiter System Mission (EJSM) had a proposed launch date in 2020, and was a joint NASA and ESA proposal for exploration of many of Jupiter's moons including Ganymede. In February 2009 it was announced that ESA and NASA had given this mission priority ahead of the Titan Saturn System Mission. EJSM consisted of the NASA-led Jupiter Europa Orbiter, the ESA-led Jupiter Ganymede Orbiter,
Mercury (planet) into an elliptical orbit, then chemical rockets will fire to deposit the mapper probe into a circular orbit. Both probes will operate for one terrestrial year. The mapper probe carries an array of spectrometers similar to those on "MESSENGER", and will study the planet at many different wavelengths including infrared, ultraviolet, X-ray and gamma ray. Mercury (planet) Mercury is the smallest and innermost planet in the Solar System. Its orbital period around the Sun of 87.97 days is the shortest of all the planets in the Solar System. It is named after the Roman deity Mercury, the messenger of the