大象传媒

In this week鈥檚 Frontiers, Andrew Luck-Baker goes to NASA鈥檚 Goddard Space Flight Centre to report on preparations for the fourth - and final - Servicing Mission to the Hubble Space Telescope.

Since its launch in 1990, Hubble has revolutionised our understanding of deep space and the universe. Its high quality images have captured the imagination of the world.

But the telescope is beginning to show its age, and NASA has announced an ambitious Servicing Mission to refurbish and upgrade Hubble.

As well as replacing batteries and gyroscopes, the astronauts will repair two instruments that have stopped working.

The Space Telescope Imaging Spectrograph (STIS) failed in 2004. The spectrograph separates light into its component colours. This allows scientists to examine a distant planet鈥檚 temperature, chemical composition, density and motion.

The Advanced Camera for Surveys (ACS) stopped working in 2007. The ACS is a wide field camera and is able to conduct broad surveys of the universe. A million second exposure on this camera produced the Hubble Ultra Deep Field Image, NASA's deepest view of the cosmos.

The astronauts will also install two new instruments. A more powerful wide field camera, Wide Field Camera 3, will carry out wide field imaging across the whole spectral range, from ultraviolet to infrared. A new spectrograph, the Cosmic Origins Spectrograph (COS), will improve Hubble's sensitivity to the spectrum.

Andrew talks to two crew members who will be part of the mission. Scott Altman will command the space shuttle. John Grunsfeld, an astronaut and astronomer, will be one of the space walkers. Both men have visited Hubble on previous servicing missions.

Andrew also talks to ex-astronaut Jeff Hoffmann and members of the support team at the Goddard Space Flight Centre.

The mission is scheduled for August 7, 2008.

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