First polar orbit around the sun (8 february 1992)
Ulysses is a decommissioned robotic space probe that was designed to study the Sun as a joint venture of NASA and theEuropean Space Agency (ESA). Originally scheduled for launch in May 1986 aboard the Space Shuttle Challenger. Due to the loss of Challenger, the launch of Ulysses was delayed until October 6, 1990 aboard Discovery (mission STS-41). The spacecraft's mission was to study the Sun at all latitudes. To do this required a major orbital plane shift. Due to velocity change limitations of the Shuttle and the Inertial Upper Stage (IUS), this was accomplished by using an encounter with Jupiter to effect the plane change instead of an engine burn. The need for a Jupiter encounter meant that Ulysses could not be powered by solar cells and was powered by a radioisotope thermoelectric generator (RTG) instead.
First mission into atmosphere of jupiter (7 december 1995)
Galileo was an unmanned NASA spacecraft which 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.
First orbit of saturn (1 july 2004)
Cassini–Huygens is a Flagship-class NASA-ESA-ASI robotic spacecraft sent to the Saturn system. It has studied the planet and its many natural satellites since arriving there in 2004, also observing Jupiter, the Heliosphere, and testing the theory of relativity. Launched in 1997 after nearly two decades of gestation, it includes a Saturn orbiter and an atmospheric probe/lander for the moon Titan called Huygens, which entered and landed on Titan in 2005. Cassini is the fourth space probe to visit Saturn and the first to enter orbit, and its mission is ongoing as of 2013.
First soft landing on titan (14 january 2005)
The Cassini-Huygens also became the first spacecraft to land on Titan (Saturn's largest moon) in January 2005. For more information about Cassini-Huygens, look directly above.