One of the longest space missions ever made came to an end on 30 June 2009 when the final command was sent to the ESA/NASA Ulysses spacecraft. Ulysses was named after a legendary Greek hero who survived numerous adventures during a 20-year “odyssey” away from home. Launched in October 1990, the spacecraft also experienced many adventures along the way, and spent almost as long exploring the unknown.
During more than 18 years in space, Ulysses achieved many breakthroughs. During a flyby of Jupiter in February 1992, the giant planet’s powerful gravity flung the spacecraft into a unique orbit which carried it far above and below the orbits of the planets. For the first time, scientists were able to make detailed studies of the Sun’s polar regions and their links with the supersonic solar wind.
Ulysses orbit animation
Ulysses’ mission was expected to end in 1995, but the tough little spacecraft just kept on going, eventually completing three passes over the Sun’s poles. Two of these took place when the Sun was in a quiet mood, while the 2000-2001 visit saw the Sun at its most violent.
Unfortunately, the nuclear power source on Ulysses gradually ran down until the intrepid voyager was struggling to operate. The shut-down of the satellite was expected to happen in 2008, but operators were able to stop it from freezing by performing a short thruster burn every two hours. However, Ulysses was moving further from Earth, and by mid-2009 poor communications meant that very few scientific data were being returned. It was time to say goodbye to the space pioneer.