Svein Hartwig Djaerff Oct 21, 2011:

Se f.eks. Wikipedia: http://en.wikipedia.org/wiki/Countdown: In the context of a rocket launch, the "T minus Time" is the time before launch, e.g. "T minus 3 minutes and 40 seconds". The last ten seconds are usually counted down aloud "10, 9, 8, 7, 6, 5, 4, 3, 2, 1, Lift off!" After a launch, most countdown clocks begin to show Mission Elapsed Time, which is typically shown as "T plus." The picture to the right shows "+ 00:00:00:07", approximately seven seconds after liftoff.