The Ulysses spacecraft, the first to reach the poles of the Sun, accomplished its task by playing planetary billiards. Most spacecraft operate in the plane of the Earth's orbit. Getting out of the plane of the Earth's orbit requires enormous energy, and Ulysses got its energy from a gravitational bounce at Jupiter.
To enable Ulysses to reach the Sun's south pole, the NASA space shuttle launched the craft toward Jupiter in October of 1990. As Ulysses flew past Jupiter, the planet's gravity pulled it around and gave it an enormous push in the direction of the south pole of the Sun. Ulysses' journey from launch to the south pole took nearly four years. The spacecraft traveled almost five years and 1.86 billion miles from launch, over the Sun's south pole and on to the Sun's north pole. The direct distance from the Earth to the Sun is 90 million miles.
Ulysses' objective is to explore the interplanetary medium at high solar latitudes. The polar passes gave scientists valuable information on the velocity and density of the solar wind and the shape of the Sun's magnetic field. The measurements are important because they will help scientists to better understand the processes that govern the Sun and its outer atmosphere. Theories on the origin of the solar wind are being revised because of the greater density and velocity of the solar wind Ulysses found at high latitudes. Scientists will have another opportunity to confirm their findings when Ulysses completes its second flight around Jupiter and returns to the Sun's south pole in 2000, and to the north pole in 2001.
Ulysses is an international cooperative project between the European Space Agency (ESA) and NASA.
Teacher's, check out the Ulysses teacher's guide.
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