An experimental satellite that launched in 1974 disappeared from ground-based sensors in the 1990s, only to be found again this week. Some defunct satellites or debris can often go missing for years,

A small, experimental satellite launched in failure in 1974 and lost to ground-based sensors for a quarter century has suddenly reappeared. On April 10, 1974, the large reconnaissance satellite KH-9 Hexagon ejected a much smaller,