UK-based satellite-phone firm Inmarsat said it had issued a default notice to LightSquared today, claiming the proposed new US wholesale LTE operator failed to pay a US$56.25 million instalment as part of a spectrum transfer between the two firms. Reuters reports that Inmarsat has given LightSquared 60 days to make the payment before it terminates the co-operation agreement. Some analysts have speculated that bankruptcy may be close at hand for LightSquared, especially after it had earlier warned that it would run out of money early this year. To makes matters worse, the FCC is planning to revoke LightSquared’s network licence because of GPS interference concerns.