/ 12 May 2009

Atlantis lifts off on final repair mission to Hubble

Space shuttle Atlantis and seven astronauts blasted off on Monday on an ambitious 11-day mission to refurbish the Hubble Space Telescope, an icon of modern astronomy that has changed scientists’ understanding of the universe.

Atlantis bolted off its seaside launch pad at 6.01pm GMT on Nasa’s 126th shuttle mission and the second of five planned for this year. The spaceship tore through partly cloudy skies, riding atop a flame-tipped pillar of smoke as it headed for Hubble’s orbit 560km above the planet.

”It’s a great day to go fly,” launch director Mike Leinbach radioed to Atlantis commander Scott Altman shortly before lift-off. ”Enjoy the ride, pal.”

Altman and his crew — pilot Greg Johnson, flight engineer Megan McArthur and spacewalkers John Grunsfeld, Michael Massimino, Michael Good and Andrew Feustel — are scheduled to catch up with Hubble on Wednesday.

McArthur will use Atlantis‘ robot arm to pluck the 13-tonne observatory from orbit and anchor it on to a work platform in the shuttle’s cargo bay.

Five consecutive days of spacewalks will follow to equip Hubble with two new science instruments, six positioning gyroscopes, batteries and fresh thermal insulation.

Astronauts also will attempt to revive two broken cameras, one of which is needed to probe the atmospheres of planets circling in other solar systems.

”On this mission, we’re going for broke,” said Hubble project scientist David Leckrone. ”We set the bar extraordinarily high for ourselves.”

Rescue shuttle ready
Nasa has dispatched space shuttle crews to repair and upgrade the 19-year-old telescope four times previously, but Atlantis‘ mission is the first since the 2003 Columbia accident, which changed the way Nasa did business.

Because the Atlantis astronauts will be too far to reach the International Space Station in case their ship sustained major damage during launch, Nasa has a second shuttle at the launch site ready to mount a rescue mission if necessary.

Nasa hopes that with the upgrades Hubble, which has cost about $10-billion so far, will last until at least 2014, at which time its replacement, the infrared-sensitive James Webb Space Telescope, should be in orbit and operational.

Hubble’s observations have been important in all areas of astronomical research, including the still-unexplained discovery that the universe is expanding at an increasingly faster rate and that galaxies formed quite early after the Big Bang explosion that created the universe 13,7-billion years ago.

If the upgrades are successful, Nasa’s highest priority is to use the new wide-field camera to take a long, deep look at the light streaming from objects formed when the universe was just about 500-million years old.

The targets are so far away that their light has shifted from visible wavelengths to the infrared, much like the shift in the sound of a train as it recedes into the distance.

Nasa also will be laying the stage for Hubble’s eventual demise. Astronauts plan to install a docking ring that can be used to automatically attach a rocket motor or other spacecraft to drive the telescope from orbit at the end of its life.

Hubble has no maneuvering engines of its own to steer away from populated areas during its eventual plunge back to Earth.

Atlantis‘ mission to Hubble is the only flight remaining in the 28-year-old shuttle programme that is not devoted to International Space Station construction and assembly.

The shuttles are scheduled to be retired in 17 months after eight more missions to the orbiting outpost. – Reuters