NASA Mission Update: ULYSSES

The sun is the source of life-sustaining energy here on Earth. Much of how it works - and affects us -- remains a source of scientific mystery. Sunspots were first recorded by humans in the 16-hundreds. Astrophysicists have since linked heightened sunspot activity with the solar wind. It's a million-mile-an-hour force of magnetically-charged particles emanating from the sun's upper atmosphere. Ebbing and flowing in minimum and maximum intensities over eleven year cycles, this so-called space weather can seriously affect how things work here on Earth, such as disrupting satellite communications, telephone service and personal electronics.

Arik Posner, Program Scientist: "It would help our technology, to safeguard the technology by knowing when and in what intensity space weather occurs and where these effects might show up"

Launch Announcer : "2 -1 ignition and liftoff of Discovery and the Ulysses spacecraft bound for the polar regions of the sun."

Until the launch of Ulysses from space shuttle Discovery in 1990, data for understanding and predicting space weather had come from a limited sampling area: the plane extending from the suns equator. Ulysses has since made three orbits above and below the poles of the sun, vastly expanding the territory from where raw space weather data are gathered.

Arik Posner: "So Ulysses was really the first spacecraft that leaped out of this confinement, and it gives us a view of the global heliosphere."

Ulysses has found that the solar minimum were in right now is producing the lowest levels of solar wind seen since accurate readings became available a half-century ago. But for heliophysicists, these data raise as many questions as they answer.

Arik Posner: "The Space Age is only 50 years now, and the Sun just operates on longer time scales than these 50 years. So we might have just glimpsed just the surface of what is really going on."

By expanding its reach, both in time and space, Ulysses is helping the discipline of space weather prediction grow beyond its infancy for the betterment of life here on Earth.

For more about Ulysses, the heliosphere, and space weather, log onto: www.nasa.gov/missions and click on 'Ulysses.'