Endeavour's replacement main engine No. 3 is moved underneath the orbiter for installation.

Endeavour's replacement main engine No. 3 is moved underneath the orbiter for installation. 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 at 1:11 p.m. EST Jan. 13, 2000, on mission STS-99. It will be Endeavour's 14th flight. STS-99 is the Shuttle Radar Topography Mission