A worker keeps check on the transfer of the Chandra X-ray as it is transferred to the KSC payload canister transporter left.

Inside the Vertical Processing Facility, a worker keeps check on the transfer of the Chandra X-ray Observatory (right) as it is transferred to the KSC payload canister transporter (left). The transporter will carry Chandra out to Launch Pad 39B for its scheduled launch, to take place no earlier than July 20 at 12:36 a.m. EDT aboard Space Shuttle Columbia, on mission STS-93. With the world's most powerful X-ray telescope, Chandra will allow scientists from around the world to see previously invisible black holes and high-temperature gas clouds, giving the observatory the potential to rewrite the books on the structure and evolution of our universe