The Hubble Space Telescope, which was launched twenty-five years ago on April 25, 1990 aboard the Endeavor space shuttle, the replacement for the Challenger shuttle that exploded shortly after launch four years earlier, has greatly expanded our knowledge of the universe. Launched with a flawed mirror, the successful attempt by NASA to repair it help show the capabilities of human astronauts in space, a fact that is important to remember at a time when some point to the achievements of our robotic space explorers as a reason why it isn’t necessary to send human beings into space, admittedly exposing them to danger and even possible death, as in the case of the brave astronauts aboard the Challenger and Columbia shuttles. The Hubble telescope has allowed up to peer billions of light-years into space to see the universe as it existed only a few billion years after the Big Bang, and has helped astrophysicists and other scientists see whether or not their theories of its origin were correct , but this, in my opinion, is not its most important achievement. More importantly.it has shown the power of the human imagination, for it was humans and not machines that first conceived the idea of putting a telescope into space (an idea first proposed by Arthur C. Clarke, the award-winning author of such science-fiction classics as 2001:A Space Odyssey and Childhood’s End) back in 1950, when the first satellite was still an idea on some engineer’s drawing board. It has allowed all of us, scientist and non-scientist alike, to see images of vast stellar nurseries in our galaxy and beyond, and to wonder whether life will someday exist on a planet orbiting one of the stars we see being born. One wonders what Galileo would think if he had the opportunity to see the Hubble pictures of the planets of our solar system, and compare them with the crude images he saw through the telescopes he built four centuries ago. Did he imagine, when he saw Saturn looking like a teacup with handles, that we would one day be able to see each of its thousands of rings, or the features of its moons? One can only wonder.
The useful life of the Hubble Space Telescope is by no means over over; scientists expect it to remain operational at least another ten years, until the year 2025, and if the longevity of the Martian rovers Spirit and Opportunity is any indication, perhaps much longer. However, because the Space Shuttle is no longer available to service it, inevitably one day its instruments will fail or lose power and the inexorable drag of the Earth’s atmosphere will cause Hubble’s orbit to decay until it is incinerated as it plunges earthwards. By that time it will probably have been superceded both in size and capacity by the Webb Space Telescope, currently scheduled to be launched in 2018. Superceded perhaps, but not replaced. Though it would nice if we could go into space and bring it back, so we could put it in the Air and Space Museum, where it belongs.