This is what is out there for satcom now;
http://www.af.mil/factsheets/factsheet.asp?id=118
http://www.fas.org/spp/military/prog...m/milstar2.htm
http://www.globalsecurity.org/space/...s/milstar3.htm
The capabilities of todays communications satellites are phenomenal and stagger the imagination. New protocols for faster and more reliable transmissions are developed every 5 years or so. However, satellites are also extremely vulnerable to external forces and evironmental phenomena among other things. Their use as a primary means of communications has become (in my opinion) to dependant. The volume of traffic is tremendous (there's not alot of bandwith out there). To much communication can be just as detrimental as not enough (micro-mangement is one thing that comes to mind). In other words satcom on the battlefield can easily become the weak link.
Before I retired there was an experimental obital system that allowed to upload/download messages on the bird every 12 hours or so... but that would't help you if you needed air support NOW... There was a pretty good HF system out there as I recall and probably shouldn't elaborate.
smitty