(09/24/1999) -- The Boeing 747 Shuttle Carrier Aircraft is cast in morning shadows as it backs away from the Mate/Demate Device with the orbiter Columbia strapped to its back. The oldest of four orbiters in NASA's fleet, Columbia is being ferried to Palmdale, Calif., where it will undergo extensive inspections and modifications in Boeing's Orbiter Assembly Facility. The nine-month orbiter maintenance down period (OMDP) is the second in Columbia's history. Orbiters are periodically removed from flight operations for an OMDP. Columbia's first was in 1994. Along with more than 100 modifications on the vehicle, Columbia will be the second orbiter to be outfitted with the multifunctional electronic display system, or 'glass cockpit.' Columbia is expected to return to KSC in July 2000