Solar probe Ulysses ends historic mission of discovery

A statement from NASA's Jet Propulsion Laboratory in Pasadena, California, said Ulysses followed programmed commands and switched off its transmitter completely at 4:15 p.m. EDT (2015 GMT).

    When Ulysses was launched from the space shuttle Discovery on Oct. 6, 1990, it had an expected lifetime of five years. However, the mission gathered unique information about the heliosphere, the bubble in space carved by the solar wind, for nearly three times longer than expected.

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 them to observe the sun over a longer period of time than ever before.

  In addition to measuring the solar wind and charged particles, Ulysses instruments measured small dust particles and neutral gases from local interstellar space that penetrate into the heliosphere. The spacecraft had an unprecedented three chance encounters with comet tails, registered more than 1,800 cosmic gamma-ray bursts, and provided findings for more than 1,000 scientific articles and two books.

    The extended mission also presented significant challenges to the NASA-European operations team. In particular, critical parts of the spacecraft became progressively colder with time. In recent years, a major effort was made to prevent the onboard hydrazine fuel from freezing. The operations team continually created methods to allow the aging space probe to continue its scientific mission, Kazinform cites Xinhua. See www.chinaview.cn for full version.