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,
Orbit of the Moon Orbit of the Moon The Moon orbits Earth in the prograde direction and completes one revolution relative to the stars in about 27.32 days (a sidereal month) and one revolution relative to the Sun in about 29.53 days (a synodic month). Earth and the Moon orbit about their barycenter (common center of mass), which lies about from Earth's center (about of the radius of Earth). On average, the distance to the Moon is about from Earth's center, which corresponds to about 60 Earth radii. With a mean orbital velocity of 1.022 km/s (0.635 miles/s), the Moon covers a distance approximately