Ganymede (moon) has an ionosphere associated with its atmosphere is unresolved. Ganymede's discovery is credited to Galileo Galilei, who was the first to observe it on January 7, 1610. The satellite's name was soon suggested by astronomer Simon Marius, after the mythological Ganymede, cupbearer of the Greek gods, kidnapped by Zeus for the purpose. Beginning with "Pioneer 10", several spacecraft have explored Ganymede. The Voyager probes, "Voyager 1" and "Voyager 2", refined measurements of its size, while "Galileo" discovered its underground ocean and magnetic field. The next planned mission to the Jovian system is the European Space Agency's Jupiter Icy Moon Explorer
Supersynchronous orbit Ariane 5 flight VA241. However, due to launch crew error resulting in anomaly and a deviation of the trajectory, the satellites were not inserted into the intended orbit, causing a reschedule of their maneuvering plan. Most natural satellites in the Solar System are in supersynchronous orbits. The Moon is in a supersynchronous orbit of Earth, orbiting more slowly than the 24-hour rotational period of Earth. The inner of the two Martian moons, Phobos, is in a subsynchronous orbit of Mars with an orbital period of only 0.32 days. The outer moon Deimos is in supersynchronous orbit around Mars. The Mars