Goodbye Ulysses

Today NASA will be shutting off one of its longer missions, the Ulysses spacecraft. Never heard of it? Not surprising. It did not get a lot of publicity in the popular media. Ulysses was launched in 1990, and swung by Jupiter 1992. Jupiter's gravity was used to change its orbit so it passed over the top and bottom of the Sun as seen from Earth (or close to the Sun's north and south poles if you prefer...not quite exactly over them as the orbit was inclined about 80 degrees). Unfortunately, Ulysses didn't take lots of pretty pictures so it wasn't a media darling.

Ulysses was studying the environment, the solar wind, the magnetic fields, and cosmic rays. Since Earth orbits in a plane that goes roughly around the Sun's equator, we have never made measurments over the poles before. Ulysses provided us with a wealth of information about this environment. Ulysses lasted 18 years, well over the length of a solar cycle so we got to see the Sun at solar maximum and some data from the currnent deep solar minimum.

There is a live webcast starting at 10:35am EDT of the switching off ceremony.

Ulysses has been a very productive craft for many years. It will be missed. Wish it could have lasted for the next solar max, but its hard to ask for more than 18 years!

Reprinted with permission from the Half-Astrophysicist Blog.