On April 24 1990, after almost two decades of design and development, one of the world’s largest and most versatile space telescopes was carried into orbit to begin its life as a vital astronomy research device.

Over the last twenty years, the Hubble telescope has captured some of the most beautiful and important images of the universe, including the famous –Ultra Deep Field’ image which is the most detailed visible-light image ever made of the universe’s most distant objects.

The Ultra Deep Field image shows nearly 10 000 galaxies, cuts across billions of light-years and is the deepest visible-light image of the cosmos. Credit: NASA, ESA, S. Beckwith and the HUDF Team

These images have led to many breakthroughs in astrophysics and astronomy, including determining the age of the universe, how galaxies are formed and the discovery of dark energy.

During its 20 year life, the Hubble telescope has been serviced four times, and is the only telescope ever designed to be fixed in space by astronauts. The most recent service was in 2009, which is expected to keep the telescope functioning until 2013, when its successor, the infrared James Webb Space Telescope is due to be launched shortly after.

Sadly, it seems impossible for Hubble to be brought back to Earth safely for museum storage, instead it will likely continue to orbit the Earth until it deteriorates and spirals back home.

The Hubble telescope was invented to solve a problem that astronomers had faced since the invention of the original telescope: the atmosphere.

The Earth’s atmosphere distorts the view of even the world’s largest and most advanced telescopes because of continuously shifting air pockets. It also blocks or absorbs some wavelengths of radiation such as ultraviolet, gamma and x rays before they reach the Earth.

Having a telescope in space away from the earth’s atmosphere means there is no atmospheric distortion so pictures can be clear and precise.

The Hubble telescope is a Cassegrain reflector telescope, which means it works by capturing light through a series of mirrors which direct the images into several science instruments that live within the telescope. Then, antennae send the information back to the Goddard Space Flight Centre in Maryland, USA. Astronomers from anywhere in the world can download the data from the internet, which can be enough to fill 18 DVDs every week.

The Hubble telescope completes an orbit of Earth every 97 minutes, mobbing at about 8km per second, fast enough to travel across Australia in about 11 minutes.

The new James Webb Space Telescope that is being created to replace Hubble will have many of the capabilities of Hubble, but also be able to study objects from the earliest universe, whose light has stretched into infrared light, or –red shifted’. It is due to be launched in 2014.

To learn more about Hubble or the James Webb Space Telescope, why not search The National Library of Australia’s Trove database. Simply enter the key words –Hubble Space Telescope’ or –James Webb Space Telescope’ in the box below! Or to find out more about Australian space activities visitwww.space.gov.au.

Much thanks to NASA for providing images and information for this story. Images are available at http://hubblesite.org/