From: JPL/ NASA Timeline: Chronicles of Discovery
August 10, 1990: Magellan enters orbit around Venus. Over the next four years, it maps 98 percent of the planet’s surface.
October 6, 1990: The U.S. – European Ulysses spacecraft launches a mission to study the Sun and its poles.
October 29, 1991: En route to Jupiter, Galileo makes the first flyby of an asteroid when it passes by Gaspra.
August 10, 1992: The U.S. – French ocean-monitoring satellite Topex/ Poseidon launches.
August 28, 1993: Galileo flies by a second asteroid, Ida, on its way to Jupiter.
December 2, 1993: Shuttle astronauts take a spacewalk to install JPL’s Wide-Field and Planetary Camera 2 in the Hubble Space telescope, compensating for a flaw in the telescope’s main mirror. The instrument allows Hubble to capture remarkable images of galaxies, nebula, planets, and many other celestial objects.
April 9, 1994: A decade after the first shuttle radar imaging mission, the third in the series launches. A JPL instrument is combined with a German-Italian radar system.
December 7, 1994: Galileo arrives at Jupiter, delivering a descent probe into the giant planet’s swirling atmosphere.
August 17, 1996: The NASA Scatterometer launches aboard Japan’s Advanced Earth Observing Satellite. The instrument studies near-surface ocean winds.
November 7, 1996: Mars Global Surveyor launches on a mission to orbit the red planet.
December 4, 1996: Mars Pathfinder launches, carrying a lander and instrumented rover.
February 12, 1997: JPL teams with a Japanese spacecraft launched under the Space Very Long Baseline Interferometry program to make radio observations of the distant Universe.
July 4, 1997: Mars Pathfinder lands, delivering the first mobile rover to another planet, By the final data transmission on September 27, the mission returns 2.3 billion bits of information, including more than 16,500 lander images and 550 rover images.
September 12, 1997: Mars Global Surveyor enters orbit.
October 15, 1997: Cassini launches to travel 6-1/2 years to Saturn, where the European-built Huygens probe will descend to the surface of the shrouded moon Titan.
February 17, 1998: Voyager 1 passes another spacecraft to become the most distant human-made object in space.
October 24, 1998: Deep Space 1 launches on a mission to flight-test advanced technologies, including an ion propulsion system.
February 7, 1999: Stardust launches on a mission to fly past a comet and return samples of comet and interstellar dust to Earth.
June 19, 1999: The Quick Scatterometer satellite launches into Earth orbit to study near-surface ocean winds around the globe.
December 18, 1999: Two JPL instruments, the Multi-angle Imaging SpectroRadiometer and the Advanced Spacebourne Thermal Emission and Reflection Radiometer, launch aboard NASA’s Terra satellite.
December 20, 1999: The Activity Cavity Irradiance Monitor Satellite launches to study the energy output of the Sun.
February 11, 2000: The Shuttle Radar Topography mission launches. The instrument uses a pair of large antennas to make a near-global map of Earth’s topography.
December 30, 2000: En route to Saturn, Cassini flies by Jupiter, making joint observations of the giant plant with the Galileo spacecraft.
April 7, 2001: Mars Odyssey launches; it enters orbit at the red planet on October 24.
August 8, 2001: Genesis launches on a mission to return samples of the solar wind to Earth.
December 7, 2001: The U.S. – French Jason 1 oceanography satellite launches.
March 17, 2002: Twin Earth-orbiting satellites are launched under the gravity Recovery and Climate Experiment mission.
May 4, 2002: JPL’s Atmospheric Infrared Sounder instrument launches aboard the Aqua satellite to study Earth’s climate and weather.
April 28, 2003: Galaxy Evolution Explorer launches to study the history of star formation.
June 10, 2003: Mars Exploration Rover “Spirit” launches to Mars.
August 25, 2003: Spitzer Space Telescope launches. It uses infrared technology to study asteroids, dust-shrouded stars, and distant galaxies.
January 3, 2004: Mars Exploration Rover “Spirit” lands at Gusev Crater on Mars.
January 24, 2004: Mars Exploration Rover “Opportunity” lands at Meridiani Planum on Mars.
March 2, 2004: JPL’s Microwave Instrument on the Rosetta Orbiter launches.
May, 2004: The Mars Exploration Rover begins the first of several extended missions.
June 30, 2004: Cassini-Huygens enters Saturn’s orbit.
July 15, 2004: JPL’s Microwave Limb Sounder and Tropospheric Emission Spectrometer launch aboard the Aura satellite to study ozone in Earth’s atmosphere.
January 12, 2005: Deep Impact launches to encounter comet Tempel 1.
January 14, 2005: The Huygens probe lands on Titan, Saturn’s mysterious smoggy moon.
July 3, 2005: Deep Impact’s impactor collides with comet Tempel 1.
August 12, 2005: Mars Reconnaissance Orbiter launches to seek out the history of water on the red planet.
July 3, 2007: Deep Impact becomes the EPOXI mission, retargeted to comet Hartley 2.
August 4, 2007: Phoenix, a Mars lander, launches to the red planet.
August 13, 2007: The Stardust spacecraft is reactivated to conduct a follow-up visit to comet Tempel 1.
September 13, 2007: Mars Exploration Rover “Opportunity” descends into Victoria Crater.
September 27, 2007: The Dawn mission to asteroid Vesta and the dwarf planet Ceres launches.
May 25, 2008: Phoenix lands near Mars’ North Pole to dig for water ice and analyze the soil.
June 20, 2008: The Ocean Surface Topography/ Jason 2 mission launches.
June 30, 2008: Cassini begins its first extended mission, called the Saturn Equinox mission.
October 22, 2008: The Moon Mineralogy Mapper launches aboard India’s Chandrayaan-1.
March 6, 2009: The Kepler mission launches on a search for Earth-like planets.
March 14, 2009: JPL technology launches on the European Space Agency’s Herschel/ Planck mission.
June 18, 2009: Diviner launches aboard Lunar Reconnaissance Orbiter to map temperatures at the lunar North Pole.
December 14, 2009: Wide-field Infrared Survey Explorer launches. It will scan the sky in infrared light, creating a vast catalog of celestial objects.
May 20, 2010: The Mars Exploration Rover project passes a historic longevity record: “Opportunity” rover surpasses the duration record set by the Viking 1 lander of 6 years and 116 days operating on the Martian surface.
September 27, 2010: Cassini begins its second extended mission, named the Cassini Solstice Mission.
November 1, 2010: The giant 70-meter (230-foot) antenna at the Goldstone Deep Space Communications goes back on line tracking deep space missions after a seven-month upgrade.
November 4, 2010: Deep Impact-EPOXI flies by comet Hartley 2.
December 25, 2010: Mars Odyssey becomes the longest-serving spacecraft at Mars – 3,340 days in orbit.
June 10, 2011: Aquarius launches to study Earth’s sea-surface salinity.
July 15, 2011: The Dawn Spacecraft enters orbit around asteroid Vesta.
August 5, 2011: Juno launches to Jupiter to explore the origin and evolution of the giant planet.
September 10, 2011: Gravity Recovery and Interior Laboratory twin spacecraft launch to explore the Moon’s gravity.
November 26, 2011: Mars Science Laboratory, “Curiosity” launches. The rover will investigate whether conditions on Mars have been favorable for life.
December 5, 2011: The Kepler Mission announces its first exoplanet in a Sin-like star’s habitable zone.