That is Periapsis or PeD on the Orbit MFD. PeD is the periapsis distance (closest point in the orbit) to the planetary body's
centre of gravity. If you are using the latest version of Orbiter this will be PeR or PeA, distance from orbit focus or
altitude from planetary surface. You can switch between these modes with Shift-D (page 49 of Orbiter Manual) or the second button down on the right of the MFD.
In either case, when you bring up the Orbit MFD, you will notice a column of green numbers on the left and (if you have your
target selected) a column of yellow numbers on the right. PeR (or PeA or used to be PeD) is the third item down in the list.
The periapsis point of your orbit is indicated on the MFD orbit diagram by the solid circle.
Editted: Oh, and don't feel dumb. This one caught a lot of people, when Martin released the new version. I don't think it has been changed yet in some of the older tutorials, so it is still catching people.
Happy flying.
Post Edited ( 09-04-05 09:27 )