Paris, July 1 (ANI): Ulysses, the joint ESA/NASA solar orbiter mission, one of the longest and most successful space missions ever conducted, has finally ended, with ground controllers sending commands to shut down the satellite's communications on June 30.
The mission had been predicted to end in July 2008, when the satellite's weakened power supply was expected to fall below the minimum required to keep fuel lines from freezing, without which Ulysses would be uncontrollable.
At that time, the ESA/NASA operations team planned to continue operating the spacecraft in a reduced capacity for a few more weeks.
However, through smart engineering and real time innovation, controllers determined they could keep the lines from freezing by briefly firing the thrusters every few hours.
In fact, Ulysses has continued gathering valuable scientific data throughout most of the past year - until June 30, after a decision was taken to end the mission due to continuing weak power and the unavailability of ground station time.
The joint ESA/NASA mission operations team under Nigel Angold, ESA Mission Operations Manager, monitored the final activity from the Ulysses Mission Support Area (MSA) at NASA's Jet Propulsion Laboratory (JPL), California, USA.
Launched by Space Shuttle Discovery on 6 October 1990, the 18-year, 8-month mission has returned a wealth of scientific data on the space environment above and below the poles of the Sun.
At the time of sending the last commands, Ulysses was located approximately 1.5 astronomical units from Earth and the one-way radio signal time was approximately 45 minutes.
"This has been an amazing adventure. Although we have said a sad farewell, Ulysses will remain a unique landmark in the exploration of space, something we can all be incredibly proud of," said Richard Marsden, ESA's Ulysses Project Scientist and Mission Manager.
During its life, Ulysses made nearly three complete orbits of the Sun.
The probe revealed for the first time the three-dimensional character of galactic cosmic radiation, energetic particles produced in solar storms and the solar wind.
Not only has Ulysses allowed scientists to map constituents of the heliosphere in space, its longevity enabled the Sun to be observed over a longer period of time than ever before. (ANI)