The Discover site has a link to KEO...
Ark de triomphe
Wanted: Your message in a time capsule designed to last 50,000 years
If there are human beings on Earth in the year 52,001, and they happen to
look to the northern sky one evening and find it filled with a shimmering aurora, they can thank
Jean-Marc Philippe for the light show. Philippe, an artist in Paris, is the creator of KEO, a
satellite designed to stay in orbit for 50,000 years. When KEO finally plunges back into the atmosphere, an ice age
or so from now, its disintegrating heat shield will generate spectacular streamers of
light--"to alert our descendants that something abnormal has happened," says Philippe. As the northern lights
fade, KEO's core, a small titanium sphere, will fall to Earth somewhere, intact. Inside will be
letters from us. Full text of this article appears in Discover magazine.