I just saw this article posted on FierceWireless. (points to FT). The irony is that this is a business that the modern cell phone nearly killed (I actually thought it had. I mean, I knew there were still a bunch of satellites orbiting the earth, but didn't know there was still a wireless service play).
In theory one should not consider sunk costs when looking forward, but it's hard to ignore the fact that investors paid only $25M for 66 satellites that Motorola and Co. spent $5 billion putting into space.
Among a host of other problems the service encounter, cost/size of handsets, cost of service and in-building coverage were a few of the more prominent ones. Competing services/technologies were also an issue. Basic physics haven't changed so it's hard to believe that all of these problems have been solved. Will be an interesting one to watch especially in light of the fact that new, high speed terrestrial networks (e.g., UMB, LTE, WiMax) are in the works.