The U.S. space shuttle Atlantis blasted off from its Florida launch pad on Monday just after 2p.m. ET on a mission to repair the Hubble Space Telescope, an important tool for scientists probing the origins of the universe.

The 11-day mission will include five spacewalks that can last up to 7 hours each. Astronauts will, for the first time, open up instruments and replace circuit boards in space. The last maintenance mission was in March 2002.

This will be the most challenging servicing mission that's been faced by our astronauts in terms of the total amount of work, said mission manager, Preston Burch.

If the mission succeeds, it will add up to five years onto the life of the 19-year-old telescope.

The space shuttle is commanded by Scott D. Altman and the crew includes Gregory C. Johnson, as pilot, and John M. Grunsfeld, Michael J. Massimino, Michael T. Good, Andrew J. Fuestel and K. Megan McArthur, as mission specialists.

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