Rob Lewis monitors Space Shuttle Endeavour's electrical system the first time the orbiter is powered up after nearly two years.

In Orbiter Processing Facility bay 2, United Space Alliance technician Rob Lewis monitors Space Shuttle Endeavour's electrical system the first time the orbiter is powered up after nearly two years. Endeavour has been in its Orbiter Major Modification (OMM) period since December 2003. Engineers and technicians spent 900,000 hours performing 124 modifications to the vehicle. These included all recommended return to flight safety modifications, bonding more than 1,000 thermal protection system tiles and inspecting more than 150 miles of wiring throughout Endeavour. Eighty five of the modifications are completed, with work on the additional 39 modifications continuing throughout the next few months. Shuttle major modification periods are scheduled at regular intervals to enhance safety and performance, infuse new technology and allow for thorough inspections of the airframe and wiring of the vehicles. This was the second of these modification periods performed entirely at Kennedy Space Center. Endeavour's previous modification was completed in March 1997.