Astronauts to repair Hubble telescope The launch is scheduled for 1801 GMT on Monday (0400 Tuesday AEST).

[link to news.theage.com.au]

Astronauts to repair Hubble telescopeMay 8, 2009
The fifth and last mission to repair the Hubble Space Telescope will be launched next week.

For nearly 20 years the telescope has kept its orbiting eye trained on the universe, providing clues about its origin and nature.

With the launch of space shuttle Atlantis to repair the ageing instrument, scientists hope to extend Hubble's life span until at least 2014.

The launch is scheduled for 1801 GMT on Monday (0400 Tuesday AEST).

It will be a marathon undertaking with five straight days of spacewalks involving adding two new instruments, repairing two others and replacing other hardware in frequently delicate operations.

Lead Flight Director Tony Ceccacci has characterised the operations as "more like brain surgery than construction," with one repair requiring the removal of 100 screws.

Since its launch in 1990, Hubble has helped scientists to place the age of the universe at 13.7 billion years, learn that black holes are at the centre of most galaxies, monitor planetary formation and discover that the universe is expanding at an ever-faster pace.

With the addition of new instruments and repairs of others, scientists still hope to learn about the gases between galaxies and take detailed pictures of extremely distant stars.

In this way, scientists can help to answer the big questions of astronomy.

"The big thing about Hubble are the discoveries that it's made and its ability to look out that 13-and-a-half billion light-years, pull all that in and take us places we can't actually go," flight commander Scott Altman said in an interview released by NASA.

"But all that information comes down through that series of boxes, the scientific instrument command and data handler. ... If that goes out, now none of those scientific discoveries, none of that, those pictures of galaxies, are able to get through and come down to the ground."

The seven-member crew of space shuttle Atlantis will use its time completing five spacewalks to get the telescope's instruments back in working order after they launch from the Kennedy Space Centre in Cape Canaveral, Florida.

The risky mission to repair Hubble has been plagued by delays, with NASA indefinitely postponing it because of problems with the orbiting telescope's mechanisms.

A launch scheduled for October 14, 2008, was cancelled.

NASA reluctantly scheduled the service mission under pressure from space enthusiasts who were alarmed at the prospect that Hubble would shut down for years until the planned 2011 launch of a successor, the James Webb Space Telescope.

Finally in 2006, NASA caved in to pressure from the US Congress and the scientific community and agreed to a repair mission.

The telescope will essentially piggyback atop the shuttle for the duration of the mission to allow astronauts to work on it.

New instruments to be added are a new wide-field camera, to replace an older model, allowing Hubble to take images in all three regions of the light spectrum, ultra-violet, visible and near infrared, and a cosmic origins spectrograph to monitor changes in light as it passes through the universe.

Additionally, spacewalkers will replace the gyroscopes that help keep the telescope pointed at a distant object, repair another camera, replace the telescope's batteries, repair a data-processing computer and install a device that will allow the telescope to be easily captured when it is time for its retirement.

All the action will be filmed by special IMAX cameras for a film, Hubble 3D, to be released next year worldwide.

But space enthusiasts won't have to wait that long to follow the mission - NASA and astronaut Mike Massimino will release updates on their Twitter accounts.

Preparations include contingency plans for damage to the shuttle. Another shuttle, Endeavour, has been moved to the launch pad and will be on standby just in case the Atlantis astronauts need to find another ride home.