Hubble at 20
One of the most famous spacecraft ever launched will celebrate its 20th birthday today: Hubble Space Telescope. Astronauts aboard space shuttle Discovery deployed the observatory on April 25th, 1990. It was the first big telescope designed to escape the blurring effects of Earth's atmosphere -- to see the universe more clearly than any other telescope.
What happened next is a saga of failure and redemption. First, Hubble became a national embarrassment when early tests showed that its primary mirror had a flaw. Its shape was off by about one millionth of an inch, so it couldn't bring light to a sharp focus.
But engineers designed corrective lenses, which a later shuttle crew installed. With its vision sharpened, Hubble became a national treasure. Its observations showed that the universe is about 13.7 billion years old. They also provided the first evidence of "dark energy" -- a force that's causing the universe to expand faster as it ages. And Hubble's pictures have adorned magazine covers, filled books, and inspired millions.
Over the years, astronauts have upgraded Hubble several times. They've switched out its batteries, computers, solar panels, and gyroscopes. And they've installed new and improved instruments that have sharpened Hubble's view even more. With a little luck, these upgrades will keep the telescope going for several more years -- perhaps long enough to celebrate its silver anniversary in 2015.
Script by Damond Benningfield, Copyright 2010
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