Ulysses

Key facts

Mission & specifications

Mission

Ulysses was the first and only spacecraft to study the Sun from above its poles, surveying our star from a vantage point no other mission has reached. A joint venture of the European Space Agency and NASA, it was deployed from the Space Shuttle Discovery on 6 October 1990. The problem it had to solve was that everything in the Solar System orbits in roughly the same flat plane, and no rocket was powerful enough to heave a spacecraft straight up out of it. So Ulysses went the long way round: it flew all the way out to Jupiter, in February 1992, and used the giant planet's gravity to wrench its orbit almost perpendicular to the planets, looping it back over the Sun's north and south poles. Over the next 17 years it made three sets of passes across the solar poles, discovering how the fast and slow streams of the solar wind are arranged by latitude, mapping the Sun's magnetic field, and sampling cosmic rays and even interstellar dust drifting into the Solar System. Designed to last five years, Ulysses operated for more than eighteen before declining power and the freezing of its fuel lines forced its shutdown on 30 June 2009.

1. 1990Deployed from Shuttle DiscoveryLaunch

   Released in Earth orbit and boosted toward Jupiter on a unique solar mission.

2. 1992Jupiter gravity assistFlyby

   Uses Jupiter's gravity to swing its orbit almost perpendicular to the planets.

3. 1994First pass over a solar poleObserved from afar

   Becomes the first spacecraft to fly over the Sun's pole, sampling the solar wind from above.

4. 1995Mapping the solar wind by latitudeMilestone

   Completes the first pole-to-pole survey, charting how the solar wind varies with latitude.

5. 2009Mission shutdownMission end

   Switched off after more than eighteen years, as its power wanes and fuel lines freeze.

Images

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