You're watching a radar screen, and dispatching space fleets to intercept
incoming space aliens. When they meet, you switch to a first person
flying screen, and promptly get blown to smithereens. Maybe I just suck
at this game, but I couldn't kill a single alien before I got blasted.
1,2,3 seem to dispatch your forces. 4-6 toggles
through incoming aliens, and 7-9 switch to battle mode.