For 1-way communications link to be viable, you can adjust a variety of parameters. There is the transmitter and receiver antenna gains (which are usually propo

For 1-way communications link to be viable, you can adjust a variety of parameters. There is the transmitter and receiver antenna gains (which are usually proportionate to antenna size), there's the datarate, and the transmit power. If you want a voice link, that means your datarate will be ion the order of ~10kbps If you want a cell phone as your transmitter, that means your antenna gain is very low, and your transmit power is also very low. The remaining free variable is the receive antenna gain. So if you put up a satellite with a large receiver antenna, then this sort of thing can work. For an example, take a look at terrestar networks' phone and satellite (http://www.terrestarnetworks.com/ http://www.terrestarnetworks.com/) . They've gone bankrupt (I think over spectrum allocation issues?) but the did functional demonstrations of their technology before going under. They had the worlds largest space-based phased array antenna system deployed.