(12/08/1999) -- Workers in the Vehicle Assembly Building move orbiter Endeavour's main engine No. 3 (in front) out of the way before moving the replacement engine into place. Following routine testing procedures on a separate test engine, analysis revealed delamination on the wall of the engine's main combustion chamber. When data revealed that one of Endeavour's engines had undergone similar testing procedures, managers opted to replace the suspect engine as a precaution. Space Shuttle Endeavour is targeted for launch on mission STS-99 on Jan. 13, 2000, at 1:11 p.m. EST. STS-99 is the Shuttle Radar Topography Mission