Historical Photo of the Month - October 2005

Ulysses
Photograph Number P-35924Ac

In October, JPL celebrates the 15th anniversary of the launch of the Ulysses spacecraft. Ulysses is a joint mission between NASA and the European Space Agency (ESA) to study the Sun. The spacecraft is shown in the European assembly facility, before it was delivered to Kennedy Space Center. Ulysses was launched on October 6, 1990 aboard Space Shuttle Discovery and sent towards Jupiter with two upper stages combined -- an Inertial Upper Stage (IUS) and a Payload Assist Module-S (PAM-S). Since no rocket engines are powerful enough to boost a spacecraft out of the Ecliptic Plane (where most planets and spacecraft orbit the Sun), Ulysses used Jupiter's gravity to bend its flight path downward and guide it onto the correct trajectory.

The purpose of Ulysses was to orbit the sun, passing over the north and south poles. It used nine instruments to study magnetic fields, solar wind, solar flares, as well as cosmic rays and cosmic dust. Ulysses flew through the tail of comet Hyakutake in May 1996, an unexpected encounter that pleased astronomers.

Ulysses was designed to complete a five-year mission, but NASA and ESA have granted three extensions, the most recent one allowing spacecraft operations to continue until March 2008. The spacecraft is currently near Jupiter, on its way back to the Sun for another south polar pass. From its inception in 1978 until 1984, it was known as the International Solar Polar Mission (ISPM), when an Italian astronomer suggested the name Ulysses.

For information about Ulysses, see the Ulysses web page or the Mission Operations Team web page. For information about Ulysses archival collections or about the history of JPL,or contact the JPL Archives.

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