NASA expects to spend at least $2.2 billion on space shuttle safety improvements through 2009.

The latest cost estimates, disclosed at a Senate Commerce Committee hearing Sept. 8, include $1.1 billion to $1.45 billion in changes NASA intends to complete prior to resuming space shuttle flights in 2005.

NASA spokesman Allard Beutel said the remainder is the cost associated with implementing all of the Columbia Accident Investigation Board’s recommendations — not just the 15 identified as prerequisites for returning to flight — and complying with higher safety standards NASA itself imposed on the shuttle program.