(AP) - A NASA spacecraft ... erupting from the surface. Discovered by Galileo in 1610, Europa is one of the four so-called Galilean moons of Jupiter, along with Ganymede, Io and Callisto.

Europa is the sixth largest satellite in our Solar System and the smallest of Jupiter’s four Galilean moons. Discovered by ...

NASA’s Galileo spacecraft gave us our best look at Ganymede’s surface. It showed icy plains, craters, and a mix of grooves and ridges which means there was probably some past geological activity.

Ganymede's surface in more detail, also compliments of Juno. Credit: NASA/JPL-Caltech/SwRI/MSSS Obviously, the 10-year-old Juno wasn't around during the previous closest flyby. The Jupiter orbiter ...

Jupiter’s Moon Ganymede: This image presents Jupiter's moon Ganymede as seen by the NASA's Hubble Space Telescope in 1996. In 1998, Hubble's Space Telescope Imaging Spectrograph took the first ...

When conducting measurements, GALA sends short laser pulses down to the surface of the icy moon currently under investigation, Europa, Ganymede or Callisto. At the surface, the pulses are reflected ...