A fifth system, Leo One, received a license on February 13. Volunteers in Technical Assistance BIG LEOs Iridium , the now-defunct system originated by Motorola. More information is available here . Globalstar , another struggling system.
More information is available here .
Ellipso has issued a lot of press releases but hasn't gotten off the ground. Constellation is basically shutdown awaiting more money. Even their website appears to be defunct. TRW's planned system, Odyssey, was scrapped right out of the starting gate. A news report regarding this decision can be found here .