KSC (or kilograms per square centimeter) was a unit of measure for pressure, equal to 1,000 GSC and approximately 1 atm or 1 bar.
In 2369, Chief of Operations Miles O'Brien requested the Deep Space 9 computer for an analysis of the operations O2 sensor readings. After the analysis, the computer reported that all sensors read between 14.3 and 14.4 KSC. (DS9: "The Forsaken")