Galileo (spacecraft)

Galileo

Artist's concept of Galileo at Io; the high-gain antenna is fully deployed
Names	Jupiter Orbiter Probe
Mission type	Jupiter orbiter
Operator	NASA
COSPAR ID	1989-084B
SATCAT no.	20298
Website	solarsystem.nasa.gov/galileo/
Mission duration	Planned: 8 years, 1 month, 19 days In orbit: 7 years, 9 months, 13 days Final: 13 years, 11 months, 3 days
Distance travelled	4,631,778,000 km (2.88 billion mi)
Spacecraft properties
Manufacturer	Jet Propulsion Laboratory Messerschmitt-Bölkow-Blohm General Electric Hughes Aircraft Company
Launch mass	Total: 2,562 kg (5,648 lb) Orbiter: 2,223 kg (4,901 lb) Probe: 339 kg (747 lb)
Dry mass	Orbiter: 1,884 kg (4,154 lb) Probe: 339 kg (747 lb)
Payload mass	Orbiter: 118 kg (260 lb) Probe: 30 kg (66 lb)
Power	Orbiter: 570 watts Probe: 730 watt-hours
Start of mission
Launch date	October 18, 1989, 16:53:40 (1989-10-18UTC16:53:40) UTC
Rocket	Space Shuttle Atlantis STS-34 / IUS
Launch site	Kennedy LC-39B
Entered service	December 8, 1995, 01:16 UTC SCET
End of mission
Disposal	Deorbited
Decay date	September 21, 2003, 18:57:18 (2003-09-21UTC18:57:19) UTC SCET
Jupiter orbiter
Spacecraft component	Orbiter
Orbital insertion	December 8, 1995, 01:16 UTC SCET
Jupiter atmospheric probe
Spacecraft component	Probe
Atmospheric entry	December 7, 1995, 22:04 UTC SCET
Impact site	06°05′N 04°04′W / 6.083°N 4.067°W / 6.083; -4.067 (Galileo Probe) at entry interface
Instruments SSI Solid-State Imager NIMS Near-Infrared Mapping Spectrometer UVS Ultraviolet Spectrometer PPR Photopolarimeter-Radiometer DDS Dust Detector Subsystem EPD Energetic Particles Detector HIC Heavy Ion Counter MAG Magnetometer PLS Plasma Subsystem PWS Plasma Wave Subsystem
NASA Flagship Program ← Voyager program Cassini–Huygens →

Galileo was an American unmanned spacecraft that studied the planet Jupiter and its moons, as well as several other Solar System bodies. Named after the astronomer Galileo Galilei, it consisted of an orbiter and entry probe. It was launched on October 18, 1989, carried by Space Shuttle Atlantis, on the STS-34 mission. 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. The data Galileo collected supported the theory of a liquid ocean under the icy surface of Europa, and there were indications of similar liquid-saltwater layers under the surfaces of Ganymede and Callisto. Ganymede was shown to possess a magnetic field and the spacecraft found new evidence for exospheres around Europa, Ganymede, and Callisto.Galileo also discovered that Jupiter's faint ring system consists of dust from impacts on the four small inner moons. The extent and structure of Jupiter's magnetosphere was also mapped.