Galileo Orbiter
NASA's Galileo Orbiter mission was launched from NASA's Space Shuttle while orbiting the Earth in October 1989, and arrived at Jupiter after getting gravity assists from a fly-by past Venus, then twice past Earth, an was inserted in an orbit around Jupiter in 1995. It carried the first entry Probe destined for an outer planet. The Galileo Probe was deployed six months before arrival at Jupiter and entered the atmosphere while the Orbiter went around Jupiter.
Galileo Orbiter became the first unmanned spacecraft to witness a celestial event - the impact of multiple fragments of comet Shoemaker Levy-9 into Jupiter in July 1994, months before it arrived at the giant planet.
Galileo Orbiter orbited Jupiter for xx years, finally ending its mission by diving into the Jupiter atmosphere on November 2003. Although its High Gain Antenna never deployed successfully, engineers were able to program the on-board computers to use data compression techniques to reduce the data volume that needed to be communicated back to Earth, enabling the return of much of the crucial science data.
