Space Shuttle Atlantis Preps for Return to Earth

The crew of the Space Shuttle Atlantis released the Hubble Space Telescope back into its orbit May 19, backed away from the telescope with a slow separation burn and then hit the thrusters to begin its return to Earth. Atlantis is scheduled for a May 22 landing at the Kennedy Space Center, from which it took off on May 11 for the 11-day mission to Hubble.

Free of Hubble, the crew stowed the equipment system that provided interfaces between the telescope and Atlantis and also served as the maintenance platform that held Hubble in place in Atlantis' bay during upgrades and repairs. The crew then began inspection of Atlantis' heat shields, which suffered what NASA called minor damage on takeoff.

According to NASA, the liftoff damaged about 25 square feet of the shuttle's launch pad flame trench, and debris from the damage apparently nicked Atlantis. NASA said Atlantis suffered minor dents along an area of about 21 inches spanning four of the shuttle's thermal tiles located on the starboard side of the spacecraft. The Atlantis crew reported May 12 they found a scratch across several heat-resistant ceramic tiles.

Heat shield damage has been a major concern for NASA since the 2003 Space Shuttle Columbia accident that killed seven crew members due to a damaged shield. Since the Columbia disaster, NASA has built in emergency plans for shuttles damaged during takeoff to seek shelter in the International Space Station. However, the flight plan to Hubble is located too far away from the ISS. Throughout the Atlantis mission to Hubble, the Space Shuttle Endeavour has been standing by on a launch pad at Kennedy Space Center in case an emergency rescue is needed.

Arriving at Hubble May 13, the crew executed five spacewalks to install a new wide-field camera, replace Hubble's six gyroscopes and install a new Science Instrument Command and Data Handling Unit, the computer that sends commands to Hubble's scientific instruments and formats scientific data for transmission to Earth.

In addition, the makeover for 19-year-old Hubble included new battery packs, a new power supply circuit board and a Cosmic Origins Spectrograph, an instrument that breaks light into component colors, revealing information about an object emitting light.

"Houston, Hubble has been released," Atlantis Commander Scott Altman radioed Mission Control at midmorning. "It's safely back on its journey of exploration as we begin the steps to conclude ours. Now Hubble can continue on its own, exploring the cosmos and bringing them home to us as we head for home in a few days."