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ShareWashington: The joint ESA/Nasa solar orbiter Ulysses is slated to shut down operations on June 30, which would mark the end of one of the most successful and longest missions in spaceflight history.
After more than 18 years in space and defying several earlier expectations of its demise, Ulysses will achieve 'end of mission' on June 30.
The final communication pass with a ground station will start at 17:35 CEST and run until 22:20 CEST on the above mentioned date or until the final command is issued to switch the satellite's radio communications into 'monitor only' mode.
No further contact with Ulysses is planned. Ulysses is the first spacecraft to survey the environment in space above and below the poles of the sun in the four dimensions of space and time.
Among many other ground-breaking results, the hugely successful mission showed that the sun's magnetic field is carried into the Solar System in a more complicated manner than previously believed. Particles expelled by the sun from low latitudes can climb up to high latitudes and vice versa.
This is very important as regions of the sun not previously considered as possible sources of hazardous particles for astronauts and satellites must now be taken into account and carefully monitored.
"Ulysses has taught us far more than we ever expected about the sun and the way it interacts with the space surrounding it," said Richard Marsden, ESA's Ulysses Project scientist and Mission manager.
The shut-down of the satellite is a joint decision of the two agencies and comes a year after the mission was expected to end. A year ago, the satellite's power supply had weakened to the point that it was thought the low temperatures would cause the fuel lines to freeze up, rendering Ulysses uncontrollable. It was decided to maintain the spacecraft in operation using Nasa's 70 m-diameter ground station network allocated on a 'spare-capacity' basis.
But as Ulysses has moved further from Earth, the communications bit-rate has gone down while other demands for the 70 m-diameter Deep Space Network stations have gone up. Most importantly, the overall return of scientific data has decreased to a level where it is hard to justify the cost of keeping Ulysses in operation.
