page_title: Galileo (spacecraft)
section_title: Jupiter science
hierarchical_section_title: Galileo (spacecraft) / Jupiter science
caption_attribution_description: Nederlands: Afbeeldingen van de vulkaan Tvashtar Catena op Io ongever een half jaar na elkaar genomen. Het vulkanisme op Io is erg dynamisch; merk op hoe de afbeeldingen verschillen. English: This pair of images taken by NASA's Galileo spacecraft captures a dynamic eruption at Tvashtar Catena, a chain of volcanic bowls on Jupiter's moon Io. They show a change in the location of hot lava over a period of a few months in 1999 and early 2000. The image on the left uses data obtained on Nov. 26 and July 3, 1999, at resolutions of 183 meters (600 feet) and 1.3 kilometers (0.8 miles) per pixel, respectively. The red and yellow lava flow itself is an illustration based upon imaging data. The image on the right is a composite using a five-color observation made on Feb. 22, 2000, at 315 meters (1030 feet) per pixel.
context_page_description: Galileo was an American uncrewed spacecraft that studied the planet Jupiter and its moons, as well as several other Solar System bodies. Named after the Italian astronomer Galileo Galilei, it consisted of an orbiter and an entry probe. It was delivered into Earth orbit on October 18, 1989 by Space Shuttle Atlantis. Galileo arrived at Jupiter on December 7, 1995, after gravitational assist flybys of Venus and Earth, and became the first spacecraft to orbit Jupiter. It launched the first probe into Jupiter, directly measuring its atmosphere. Despite suffering major antenna problems, Galileo achieved the first asteroid flyby, of 951 Gaspra, and discovered the first asteroid moon, Dactyl, around 243 Ida. In 1994, Galileo observed Comet Shoemaker–Levy 9's collision with Jupiter.
  Jupiter's atmospheric composition and ammonia clouds were recorded, the clouds possibly created by outflows from the lower depths of the atmosphere. Io's volcanism and plasma interactions with Jupiter's atmosphere were also recorded.
context_section_description: After arriving on December 8, 1995 (UTC), and completing 35 orbits around Jupiter throughout a nearly eight-year mission, the Galileo orbiter was destroyed during a controlled impact with Jupiter on September 21, 2003. During that intervening time, Galileo changed the way scientists saw Jupiter and provided a wealth of information on the moons orbiting the planet which will be studied for years to come. Culled from NASA's press kit, the top orbiter scientific results were:
  Galileo made the first observation of ammonia clouds in another planet's atmosphere. The atmosphere creates ammonia ice particles from material coming up from lower depths.
  The moon Io was confirmed to have extensive volcanic activity that is 100 times greater than that found on Earth. The heat and frequency of eruptions are reminiscent of early Earth.
  Complex plasma interactions in Io's atmosphere create immense electrical currents which couple to Jupiter's atmosphere.
  Several lines of evidence from Galileo support the theory that liquid oceans exist under Europa's icy surface.
  Ganymede possesses its own, substantial magnetic field – the first satellite known to have one.
  Galileo magnetic data provided evidence that Europa, Ganymede and Callisto have a liquid salt water layer under the visible surface.
  Evidence exists that Europa, Ganymede, and Callisto all have a thin atmospheric layer known as a 'surface-bound exosphere'.
  Jupiter's ring system is formed by dust kicked up as interplanetary meteoroids smash into the planet's four small inner moons. The outermost ring is actually two rings, one embedded with the other. There is probably a separate ring along Amalthea's orbit, as well.
  The Galileo spacecraft identified the global structure and dynamics of a giant planet's magnetosphere.
caption: Tvashtar Catena on Io, showing changes in hot spots between 1999 and 2000
exif: {}