20-09-2008 Last Shuttle visit to Hubble (Article155)

Moderator: SAC Committee

Post Reply
Simon Kenny
Posts: 527
Joined: Tue Feb 12, 2008 9:17 pm
Location: Shannon, Co. Clare, Ireland

20-09-2008 Last Shuttle visit to Hubble (Article155)

Post by Simon Kenny » Tue Dec 30, 2008 8:54 pm

Last Shuttle visit to Hubble Space Telescope (Article155)

Edwin Hubble was one of the greatest astronomers of the 20th Century. In the 1920s he made the then astonishing discovery that Our Milky Way was not the entire universe, but was only one of millions of galaxies in an unimaginably large cosmos. He went on to discover that galaxies are retreating from each other and that the universe itself is expanding at a constant rate, now known as the Hubble Constant.

Today, the first of NASA’s four great orbiting observatories, named after Edwin Hubble, continues his legacy of cosmic discoveries with unprecedented insights into previously unseen and often unimagined corners of the universe. Launched in 1990, the venerable old 2.4 metre telescope is kept operating at its full powers by constant maintenance and replacement of its working parts by visiting astronauts from the Space Shuttle. While Hubble’s mirror is not big by earthly standards, its position in space above the atmospheric interference gives it unique advantages over ground based observatories and enables it to see the cosmos with breathtaking clarity. Some of its photographs can be seen on http://heritage.stsci.edu/gallery/galindex.html . Hubble was designed to observe the visual part of the electromagnetic spectrum, the part we can see and also the ultraviolet and near infrared at either side of the visual spectrum. Appropriately, the telescope was used in 2001 to confirm the discoveries of its famous namesake. The rate of the universe’s expansion, or Hubble’s constant was set at about 72 km per second per Megaparsec (Mpc) where 1 parsec equals 3.2 light years of distance. That wasn’t all. It also helped discover that the expansion of the universe is accelerating. The cause of this, the so-called ‘dark energy’ fuelling the accelerating expansion, is still a mystery.

Hubble is due its fourth, and probably its last servicing mission in October 2008 — the Shuttle launch date is scheduled for the 10 October. It will be fitted with state-of-the-art equipment to improve its image quality and operational lifespan even further. Hubble is expected to continue as a cutting edge instrument until 2013, when the James Webb space telescope replaces it.

At the end of its service life, it was originally planned that the space shuttle would bring it back to Earth where it would go on display, but due to the recent destruction of the shuttle Columbia, all non essential missions were scrapped and now the HST will fall into the Earths atmosphere where it will burn up - an ignominious end to what has been up to now the most important telescope in history.

Post Reply