A kilopascal is a measurement of pressure, similar to psi. It's a commonly used metric term, but for the mechanically minded it is not clear, like grams per square centimeter would be. Atmospheres (bar) is useful also. For a rocket scientist, kilopascal is more convenient when working in places other than the surface of the earth or to high precision. For me a useful number is that a psi equals about 7 kilopascals. I like the metric system, just not this particular convention.