Laplace-P that would have studied the Jovian moon system as well as the planet Jupiter. The orbiter would have done several flybys of other Jovian moons before being placed in orbit around Europa. The lander would have researched the ocean underneath the ice sheet of Europa. However, to avoid the damaging effects of Jupiter's radiation belts, the destination of the lander was switched in 2011 from Europa to Ganymede. Ganymede is the largest moon in the Solar System and has an internal ocean that may contain more water than all of Earth's oceans together. The orbiter would perform 13 flybys of
Ganymede (moon) Relatively young craters with rays of ejecta are also visible. Ganymedian craters are flatter than those on the Moon and Mercury. This is probably due to the relatively weak nature of Ganymede's icy crust, which can (or could) flow and thereby soften the relief. Ancient craters whose relief has disappeared leave only a "ghost" of a crater known as a palimpsest. One significant feature on Ganymede is a dark plain named Galileo Regio, which contains a series of concentric grooves, or furrows, likely created during a period of geologic activity. Ganymede also has polar caps, likely composed of water frost.