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Ulysses mission graphic

Phase: Past

Launch Date: October 06, 1990

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Program(s):Heliophysics Research

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The primary mission of the Ulysses spacecraft was to characterize the heliosphere as a function of solar latitude. The heliosphere is the vast region of interplanetary space occupied by the Sun's atmosphere and dominated by the outflow of the solar wind. The periods of primary scientific interest is when Ulysses was at or higher than 70 degrees latitude at both the Sun's south and north poles. Ulysses launched on October 6, 1990 and in June 1994 it began a four-month observation from high latitudes of the complex forces at work in the Sun's outer atmosphere-the corona.

Scientists have long studied the Sun from Earth using Earth-based sensors. More recently, solar studies have been conducted from spaceborne platforms; however, these investigations have been mostly from the ecliptic plane (the plane in which most of the planets travel around the Sun) and no previous spacecraft have reached solar latitudes higher than 32 degrees. Ulysses high latitude data helped scientists from the joint NASA and ESA mission obtain new and better understanding of the processes going on at high solar latitudes.

Original Ulysses Mission science objectives are to investigate for the first time as a function of heliographic latitude the properties of the solar wind, the structure of the Sun/wind interface, the heliospheric magnetic field, solar radio bursts and plasma waves, solar X-rays, solar and galactic cosmic rays, and both interstellar and interplanetary neutral gas and dust. Additional objectives included the Study of the Jovian magnetosphere during the Jupiter flyby, the detection of cosmic gamma ray bursts and triangulation on burst locations with other detectors and the Search for gravitational waves.

New objectives evolving since launch were to combine Ulysses in situ measurements of solar wind fields and particles, cosmic rays, and radio waves over a wide range of heliolatitudes and radial distances with remote observations of the Sun and solar corona from ongoing and upcoming missions to analyze properties and dynamics of coronal mass ejections and of sources of the solar wind in order to enhance the ability of those missions to meet their own science objectives and to construct models of the 3D Sun and heliosphere.

The spacecraft and spacecraft operations team were provided by the European Space Agency (ESA); the launch of the spacecraft, radio tracking, and data management operations are provided by NASA. Scientific experiments were provided by investigation teams both in Europe and the USA.