Mission Details

Landmark Dates	Craft	Destination
Galileo Launched: 18 Oct 1989 Arrived: 7 Dec 1995	Galileo	Jupiter

Jumping Jupiter!

Galileo's primary objective was to study Jupiter's atmosphere, magnetosphere and the four larget moons for two years (1995-1997). In an extended mission, for two more years (1997-1999) Galileo was to study in further detail and closer range Jupiter's icy moon Europa and its volcanic moon Io.

 

To archieve the objectives the mission comprised an orbiter which would make detailed measurements of Jupiter and its moons over a number of years. The chemistry and structure of the jovian atmosphere was to be analysed by a decending probe. The faulty deployment of the high-gain antenna has, however, caused severe problems. Galileo achieved the first atmospheric probe entering Jupiter's atmosphere in December 1995 and spent nearly and hour taking measurements before the massive pressure crashed it. Measurements showed that the outer edge of the Great Red Spot may be as much as 10 km lower than the rest of the cloud within it. The outer part appears to rotate with a period of 4 to 6 days; near the centre motions are small and more random in direction. In Europa, it found evidence of cryvolcanism, where water ice is spurted out from the interior in a similar way to lave from volcanoes on Earth. Key Mission Results: Galileo's probe discovered massive thunderstorms caused by circulation of the atmsophere from the upper to lower levels. Before it entered the atmosphere, the probe detected a very intense radiation belt. Measuring the surface temperature of Io and determining that some of the volcanoes are hot. Detection of ice rafts on Europa that are breaking apart and drifting this is accompanied with new material bubbling up from below. Discovery on Europa of a thin oxygen atmosphere and an ionosphere. Ganymede has a magnetic field associated with a liquid iron core caused by tidal heating from an earlier different orbit. Evidence of a sub-surface salty ocean on Callisto detected by a magnetic field caused by electric currents in the water which are in-turn caused by Callisto moving through the jovian magnetic fields. Magnetic reading from May 2000 are highly suggestive that a salty ocean exists 120 miles under Ganymede's crusty surface.

Galileo was the first spacecraft ever to flyby an asteroid (Gaspra).