The Soviet Union’s Sputnik 1 satellite fell out of orbit long ago. So did Sputnik 2, as well as America’s first satellite, Explorer 1. Yet Vanguard I, the second satellite launched into space by the United States, is still orbiting the planet. It weighs just three pounds, a fact that inspired Soviet premier Nikita Khruschev to mock it as “the grapefruit satellite.” This little device outlived Khruschev’s Communist empire, of course. It has now zipped around the planet more than 178,000 times, and scientists still find ways to use it. Vanguard 1 went into the heavens exactly 45 years ago today.