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
Triton (moon) more than 99.5% of all the mass known to orbit Neptune, including the planet's rings and thirteen other known moons, and is also more massive than all known moons in the Solar System smaller than itself combined. Also, with a diameter 5.5% that of Neptune, it is the largest moon of a gas giant relative to its planet in terms of diameter, although Titan is bigger relative to Saturn in terms of mass. It has a radius, density (2.061 g/cm), temperature and chemical composition similar to those of Pluto. Triton's surface is covered with a transparent layer of annealed frozen