One of the finalists for the European Space Agency's next big robotic science mission is the Europa Jupiter System Mission (EJSM) that would send a probe each to orbit Europa and Ganymede, moons of Jupiter.

Under the EJSM, NASA would build and operate the Europa orbiter and the ESA would build and operate the Ganymede orbiter.
Each mission could be conducted independently, but there would be more scientific benefit from a joint mission since each satellite would also examine Jupiter's atmosphere and magnetosphere.
Each probe would initially orbit Jupiter before inserting into orbit around their target moon and would spend several months examining the Jovian system, its satellites, and how Jupiter's moons and the planet itself interact.
The Jupiter Europa Orbiter, after a 30-month Jupiter orbit phase in which it would encounter the moons Io, Ganymede, and Callisto as well as Europa, would settle into Europa orbit in a 200-kilometer orbit.
The JEO would examine Europa's ice shell, its ocean, as well as its chemistry, geology and potential habitability for a nine-month mission.
The Jupiter Ganymede Orbiter would spend 11 months orbiting Jupiter, conducting similar observations of the Jovian system as the Jupiter Europa Orbiter. Then the JGO would insert into orbit around Ganymede to study its geology and its potential for habitability in a 13-month mission.
Exact launch times are dependent on funding. A sample mission would have both the JEO and the JGO launching in 2020 and arriving in the Jovian system in 2025 or 2026 after a trajectory that would allow the two probes to use Venus and Earth as gravity assists to boost their speed.
The Jupiter Europa Orbiter would enter Europa orbit in July 2028. The Jupiter Ganymede Orbiter would enter Ganymede Orbit in May 2028.
Each probe would impact its target moon after running out of orbiting maneuvering fuel.
The Europa Jupiter System Mission follows an overreaching goal of finding extraterrestrial life, almost certainly microbial, that has been pursued by NASA and the ESA for decades. So far that search has focused on Mars, with somewhat inconclusive results. Should either Europa or Ganymede or both moons be found to be habitable, then the next step would be an attempt to land some kind of probe.
Ganymede would likely get some kind of lander/rover similar to those sent to Mars. Europa, which is covered with ice below which is surmised to be an ocean, might get some kind of penetrator that would attempt to break through to the subsurface ocean and examine its characteristics first hand.
(Source: ContributorNetwork)