User:Xession/Draft3
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Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. Named after the astronomer and Renaissance pioneer Galileo Galilei, it was launched on October 18, 1989, by the Space Shuttle Atlantis on the STS-34 mission. It arrived at Jupiter on December 7, 1995, a little more than six years later, via gravitational assist flybys of Venus and Earth.
{{Infobox spacecraft | Name = ''Galileo'' Orbiter | Image = [[Image:Galileo_arrival_at_Jupiter.gif|290px]] | Caption = ''Galileo'' is prepared for mating with the [[Inertial Upper Stage|IUS]] booster | Organization = [[NASA]] | Major_Contractors = | Mission_Type = [[Orbiter]], Fly-by | Flyby_Of = [[Venus]], [[Earth]], [[951 Gaspra]], [[243 Ida]] | Satellite_Of = '''[[Jupiter]]''' | Orbital_Insertion_Date = 1995-12-08 01:20:00 UTC | Launch = 1989-10-18 16:53:00 UTC | Launch_Vehicle = [[Space Shuttle Atlantis]] <br>[[Inertial Upper Stage]] | Launch_Site = [[Kennedy Space Center Launch Complex 39|KSC Launch Complex 39B]] <br>[[Kennedy Space Center]] | Decay = | Mission_Duration = December 8, 1995 - <br>September 21, 2003 <br><br>(deorbited 2003-09-21 18:57:00 UTC) | NSSDC_ID = 1989-084B | Webpage = [http://www2.jpl.nasa.gov/galileo/ ''Galileo'' Project Home Page] | Mass = {{convert|2380|kg|abbr=on}} | Power = 570 W ([[Radioisotope thermoelectric generator|2 RTGs]]) | Orbital_elements = | Semimajor_Axis = | Eccentricity = | Inclination = | Orbital_Period = | Apoapsis = | Periapsis = | Orbits = }}
Despite antenna problems, Galileo conducted the first asteroid flyby near 951 Gaspra, discovered the first asteroid moon Dactyl around asteroid 243 Ida, was the first spacecraft to orbit Jupiter, and launched the first probe into Jupiter's atmosphere.[1]
The spacecraft measured atmospheric composition of Jupiter and directly observed ammonia clouds, which seems to be created from an outflow from lower depths. It also registered Io's volcanism and plasma interactions between the atmosphere with currents from Jupiter's atmosphere. Other studies gave support for the popular theory of liquid oceans under the icy surface of Europa. There was also indications of similar liquid-saltwater layers under the surfaces of Ganymede and Callisto, while Ganymede was shown to possess a magnetic field. New evidence was also found for existence of exospheres around Europa, Ganymede, and Callisto.[1]
It was discovered that Jupiter's faint ring system is formed by dust from impacts on the four small inner moons. The extent and structure of Jupiter's magnetosphere was also mapped.[1]
Galileo was the only direct observation point of comet Shoemaker-Levy 9's impact into the atmosphere of Jupiter.[1]
On September 21, 2003, after 14 years in space and 8 years of service in the Jovian system, Galileo's mission was terminated by sending the orbiter into Jupiter's atmosphere at a speed of nearly 50 kilometres per second to avoid any chance of it contaminating local moons with bacteria from Earth. Of particular concern was the ice-crusted moon Europa, which, thanks to Galileo, scientists now suspect harbors a salt water ocean beneath its surface.