Galileo, named after Italian astronomer Galileo Galilei, taught us much about Jupiter and its moons. Launching into space with a Titan IV rocket, its speed increased when passing Venus and Earth; eventually reaching Jupiter in 1995.
Galileo made numerous remarkable discoveries during its two years orbiting Jupiter, including lava flows on Io and evidence for saltwater oceans below Europa’s surface. Additionally, Galileo witnessed Comet Shoemaker-Levy 9 colliding with Jupiter.
Overview of the Mission
Galileo Galilei was an Italian astronomer and this mission featured two spacecraft: an orbiter and probe. Two long-lived radioisotope thermoelectric generators converted heat from plutonium decay into electricity powering both vehicles.
Galileo’s mission has made many key discoveries about Jupiter and its moons, including confirmation that the gas giant possesses a magnetic field as well as witnessing comet Shoemaker-Levy 9 colliding into Jupiter’s clouds and shattering into pieces.
Jupiter was studied during its observations of its banded atmosphere of reds and creams, which revealed its powerful equatorial jet streams, swirling eddies, and centuries-old Great Red Spot.
Flybys of Europa have provided valuable insight into its mysterious volcanic activity, raising the possibility that liquid oceans might exist beneath its frozen surface. Furthermore, Enceladus’ detection of an ocean beneath its icy surface suggests it too may contain subsurface oceans.
Galileo’s Orbit
Galileo was the first spacecraft ever sent into orbit around and study of Jupiter. It studied Jupiter’s magnetosphere and conducted two close encounters of Europa – gathering important information on its volcanic surface while raising suspicion that liquid oceans lay beneath. Furthermore, Galileo performed its first flyby imaging of an asteroid (Gaspra) and observed a comet colliding with one of Jupiter’s atmosphere (Shoemaker-Levy 9).
Galileo has been extended three times to take full advantage of its spacecraft’s unique abilities. Passive Hydrogen Maser atomic clocks offer unmatched precision and stability, making the Galileo satellites perfect for testing new navigation and timing technologies. Furthermore, they are equipped with laser retroreflector arrays for independent orbit tracking by satellite laser ranging stations which allows verification of onboard navigation messages’ accuracy as well as disentanglement of clock errors from planetary orbit radial error sources; yet these tests do not interfere with normal operation or Search and Rescue services services in any way.
Galileo’s Instruments
Galileo was an engineer-scientist in Venetian Republic who applied his technical knowledge to solve civic, military and nautical problems. Using telescopes that magnified objects three to nine times, Galileo displayed one such instrument before the Senate for display.
Galileo completed its primary mission by visiting four of Jupiter’s moons: Ganymede, Io, Callisto and Europa in six flybys each and collecting detailed information about their sizes, composition and features.
After Galileo entered its second orbit, hardware changes improved the spacecraft’s ability to communicate with Earth, increasing the average telemetry rate by 10 times. In addition, the Galileo project developed a quadruple redundant data processing system on board that could keep functioning even if two of its three space-qualified atomic clocks failed, providing for smooth operations even if two clocks went offline simultaneously. Now this receiver is being utilized in testing new Galileo Second Generation signals and services like Quasi-Pilot and Data Signal.
Galileo’s Deorbit
Galileo finally reached Jupiter orbit after an eventful six-year journey that included gravity-assist maneuvers around Venus, Earth, and Gaspra. It completed close flybys and imaging of both these objects as well as Ida. Furthermore, Galileo observed comet Shoemaker-Levy 9 when it struck Jupiter in 1994, as well as studying its magnetic environment for the longest period yet.
Engineers had determined that two years of intense radiation had put undue strain on their spacecraft, leaving its propellant nearly depleted. Engineers determined that sending it intentionally into Jupiter’s atmosphere in an controlled crash would prevent accidental contamination by forward debris while keeping its mission viable.
Galileo recorded numerous scientific findings with its mission, such as evidence supporting the theory that Europa contains a liquid ocean; mapping Jupiter’s composition and ammonia clouds; discovering magnetic fields on Ganymede and Callisto moons, mapping its rings as they formed from impact debris from four inner moons, as well as mapping and studying their formation by impact debris from four outer moons.