Veteran astronaut Scott Altman commands the STS-125 mission, with retired Navy Capt. Gregory Johnson serving as pilot. The crew also includes veteran spacewalkers John Grunsfeld and Mike Massimino, and first-time space fliers Andrew Feustel, Michael Good and Megan McArthur.
During the 11-day mission the National Aeronautics and Space Administration astronauts will perform five spacewalks, installing two new instruments, repairing two inactive ones and making component replacements that will keep the telescope functioning until at least 2014.
The servicing mission, the fifth, is designed to update Hubble, which has been in operation for 19 years. NASA said Hubble, after it is upgraded, will be 100 times as powerful as it was when it went into orbit in April 1990.