Galileo (spacecraft)

Artwork Galileo-Io-Jupiter.JPG
Artist's concept of Galileo at Io with Jupiter in the background; the high-gain antenna is fully deployed
NamesJupiter Orbiter Probe
Mission typeJupiter orbiter
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 travelled4,631,778,000 km (2.88 billion mi)[1]
Spacecraft properties
Launch mass
  • Total: 2,562 kg (5,648 lb)[2]
  • Orbiter: 2,223 kg (4,901 lb)[2]
  • Probe: 339 kg (747 lb)[2]
Dry mass
  • Orbiter: 1,884 kg (4,154 lb)[2]
  • Probe: 339 kg (747 lb)[2]
Payload mass
  • Orbiter: 118 kg (260 lb)[2]
  • Probe: 30 kg (66 lb)[2]
  • Orbiter: 570 watts[2]
  • Probe: 730 watt-hours[2]
Start of mission
Launch dateOctober 18, 1989, 16:53:40 (1989-10-18UTC16:53:40) UTC[4]
RocketSpace Shuttle Atlantis
STS-34 / IUS
Launch siteKennedy LC-39B
Entered serviceDecember 8, 1995, 01:16 UTC SCET[3]
End of mission
DisposalControlled entry into Jupiter
Decay dateSeptember 21, 2003, 18:57:18 (2003-09-21UTC18:57:19) UTC SCET[1]
Jupiter orbiter
Spacecraft componentOrbiter
Orbital insertionDecember 8, 1995, 01:16 UTC SCET[3]
Jupiter atmospheric probe
Spacecraft componentProbe
Atmospheric entryDecember 7, 1995, 22:04 UTC SCET[3]
Impact site06°05′N 04°04′W / 06°05′N 04°04′W / Galileo Probe)
at entry interface
Galileo mission patch.png 

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 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.[5] 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.[5]

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.[5] 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.[5]

On September 21, 2003, after 14 years in space and 8 years in the Jovian system, Galileo's mission was terminated by sending it into Jupiter's atmosphere at a speed of over 48 kilometers per second (30 mi/s), eliminating the possibility of contaminating local moons with terrestrial bacteria.


Jupiter was rated as the number one priority in the Planetary Science Decadal Survey published in the summer of 1968.[6] In the early 1970s the first flybys of Jupiter were achieved by Pioneer 10 and Pioneer 11, and before the decade was out it was also visited by the more advanced Voyager 1 and Voyager 2 spacecraft.

Other Languages
Alemannisch: Galileo (Raumsonde)
azərbaycanca: Qalileo (kosmik gəmi)
čeština: Galileo (sonda)
Bahasa Indonesia: Galileo (wahana antariksa)
italiano: Sonda Galileo
Lëtzebuergesch: Galileo (Raumsond)
magyar: Galileo
norsk nynorsk: Romsonden Galileo
Simple English: Galileo (spacecraft)
slovenščina: Galileo (sonda)
srpskohrvatski / српскохрватски: Galileo (svemirska letjelica)
Tiếng Việt: Galileo (tàu vũ trụ)