Arrived at Venus in April 2006. ESA announced on December 16, 2014 that the mission had ended.
Sent to orbit Mercury. Flew by Venus twice on its way. Instructed to impact on the surface on April 30, 2015. Since Mercury is so close to the Sun it’s not that easy to send a probe there. It needs a lot of fuel to slow down the spacecraft when reaching the planet. Mercury has not enough atmosphere for aerobraking. Only Mariner 10 has been there before MESSENGER. At one time MESSENGER shut down to safe mode but recovered after a couple of hours, losing some of the collected data and images. In total MESSENGER took 100 000 pictures and 10 terabyte of data was collected. One of the discoveries on this warm planet was ice at the north pole and a complete map of Mercury.
Target: Saturn and moon Titan. The Cassini spacecraft is the first probe to orbit around Saturn which it reached on July 1, 2004. On December 25 the Huygens probe separated and reached Saturn’s moon Titan on January 14 2005 and descended to the surface. ESA website for Cassini here. ASI website for Cassini here.
In 2008 Cassini flew by moon Enceladus and discovered plumes of water coming from the moon.
Target: Gaspra / Ida / Jupiter. Reached Jupiter in December 1995. Mission ended on September 21, 2003 when the spacecraft was sent into Jupiter’s atmosphere. Galileo was the second spacecraft to be launched from the Space Shuttle (STS-34). After a Venus (and Earth) flyby Galileo passed asteroid 951 Gaspra and discovered the first asteroid moon, Dactyl, around asteroid 243 Ida. Galileo also observed comet Shoemaker-Levy 9‘s collision with Jupiter. It also studied Jupiter’s moons: Io, Europa, Ganymede and Callisto. Even though Galileo was built to resist radiation instruments started to behave strange when getting close to Jupiter. Pictures went white, a radio transmitter shifted frequency and the gyro wasn’t working properly. One antenna also failed because the spacecraft had been in storage for more than four years after the Challenger disaster. With one failed antenna and reduced transmitting capacity data had to be put on tape before it could be sent back to Earth. But the 114 megabyte tape recorder also suffered from issues. It was repaired remotely but part of the tape was damaged. To make space for Jupiter data most of the data from the moons were erased. When studying another moon, Amalthea, the tape recorder stopped responding and later radiation made the instruments on Galileo to shut down. It was later discovered that the moon data had been written to the tape anyway.
On 7 December 1995 when Galileo reached Jupiter, a probe was released from the spacecraft to descent through Jupiter’s atmosphere. It lasted for 78 minutes. The probe was followed by the Galileo spacecraft in 2003.