dscc9726.jpg

Detail of one of the yaw thrusters. It reads

[unintelligible, but perhaps "V"]36-417011-89
S/C 107

Columbia was Apollo spacecraft (aka "S/C") #107 (the "1" indicating that it was a Block II, rather than Block I spacecraft, and "07" indicating that it was the seventh spacecraft in the series).

Michael Collins, Apollo 11 Command Module Pilot, was fond of S/C 107; he wrote the following on a spacecraft panel:

Spacecraft 107 - alias Apollo 11
alias "Columbia"
The Best Ship to Come Down the Line
God Bless Her