23-06-2007 Space telescopes (Article 91)

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Simon Kenny
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Location: Shannon, Co. Clare, Ireland

23-06-2007 Space telescopes (Article 91)

Post by Simon Kenny » Wed Feb 04, 2009 11:03 am

Space telescopes (Article 91)

As stated in an earlier article, there are unavoidable limitations on the size of ground based telescopes. However, the dawn of the space age has created new possibilities. The development of rocket science has inspired huge leaps in the advancement of electronics and robotics. This, in turn, has had an explosive effect on the development of the tools of astronomy, especially the telescope and hence upon the recent rapid expansion of our knowledge of the cosmos.

Since its invention by the Chinese in the Middle Ages, the impetus on rocket development was slow, as it was seen as an exotic curiosity, of little practical value except for the entertainment and spectacle of fireworks. As rocket science advanced in the second half of the Twentieth Century, astronomers quickly saw the advantage of putting a telescope completely above the Earth’s atmosphere, but before this could happen, several problems needed addressing. The first was that the powerful rockets needed to launch a sizable telescope were an expensive and scarce resource and were kept for projects that had greater public impact, such as landing men on the Moon. Over time, the long term benefits of sending astronomical observatories into space were recognised. This in turn led to the development, first of the space probes like the Pioneer series in the 1970s in the US and the Venera series in the Soviet Union. Inevitably, advancing technology made the option of putting a permanent telescope in Earth orbit a serious possibility.

Getting a telescope into space was only one problem. It also needed to be precisely controlled and directed. Controlling and pointing a sensitive instrument orbiting the Earth at several kilometres per second posed huge problems initially. The development of other space technology, such as inertial guidance, to precisely control the pointing of the telescope and the advancement of electronics, eventually made the creation of stable, robotically controlled space telescopes a reality in early 1990s when the Hubble Space Telescope was launched into earth orbit. How well the scientists overcame these difficulties is attested to in the wealth of wonderful images Hubble has captured since its launch, many of which can be viewed on its website: http://hubblesite.org . The Hubble telescope also proved that it was possible to perform maintenance and upgrades to orbiting observatories. The first and most spectacular was a performed by Space Shuttle astronauts to Hubble’s main mirror. The upgrade enabled Hubble to photograph the cosmos with awesome clarity. This maintenance work on Hubble eventually became routine, increasing its powers and longevity. The age of the Great Space Observatories had finally arrived.
Clear skies!

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