From Rise: The Vieneo Province - The Space Simulator MMO from Unistellar Industries, LLC
Indicated air speed is a measurement of the difference between the pressure of ram air and the static (surrounding or ambient) pressure. As the outside air pressure decreases, indicated air speed will drop. In space there is very little air and therefore little or no indicated air speed. The air data is gathered by air data probes; the ram air reading is gathered by one or more "pitot tubes" (which are oriented in the normal direction of travel and therefore only register forward air speed) and one or more "static ports" that sit flush on the fuselage.
True Air Speed is the speed a vehicle is passing through the air corrected for pressure. A simple way of thinking about this, TAS is your ground speed plus or minus any winds.
Ground speed is the rate you are traveling over the ground in Km/Sec.
Is the speed you are climbing or descending measured in Km/sec
All these speeds can be found on calculated from the main instruments
rana 15:32, 14 March 2007 (HKT)