LightSquared Delivers Notice to Inmarsat Triggering Re-banding of L-Band Radio Spectrum in North America

RESTON, Virginia, August 18, 2010 - LightSquared, the nation's first wholesale-only integrated wireless
broadband and satellite network, today announced it has delivered notice to
Inmarsat triggering Phase 1 of a Cooperation Agreement between Inmarsat and
LightSquared.

Under the Cooperation Agreement originally signed in December 2007,
Inmarsat and SkyTerra (now LightSquared), designed a phased plan aimed at
addressing growing wireless broadband demand. The agreement increases the
amount of contiguous spectrum available to both parties and provides
LightSquared enhanced operational flexibility for deployment of its 4G-LTE
integrated terrestrial and satellite network.

"Implementation of this agreement represents a significant milestone in
LightSquared's plan to build the nation's first wholesale only 4G-LTE
wireless broadband network," said Sanjiv Ahuja, chairman and chief executive
officer of LightSquared. "Triggering this agreement will now give us the
contiguous spectrum we need to support additional network capacity to meet
the growing demand for wireless data."

To implement Phase 1, Inmarsat will immediately begin a process of
transition to a modified spectrum plan to increase spectrum contiguity. This
process is expected to take 18 months and will require Inmarsat to incur the
cost of certain network modifications. During implementation of Phase 1,
LightSquared will make a series of payments to Inmarsat totalling $337.5
million (USD):

    - Upon exercise, LightSquared made an initial payment of $81.25 million
      (USD) ($31.25 million (USD) plus first installment of $50 million
      (USD)).
    - Following the initial payment of $81.25 million (USD), LightSquared
      will pay $40 million (USD) every three months until the final $40
      million (USD) installment is paid 15 months from the trigger date.
    - At the Phase 1 completion date (targeted for 18 months following the
      trigger date), LightSquared will pay another $56.25 million (USD).

Additionally, LightSquared has an option to implement Phase 2 which will
add further capacity to its network. Phase 2 may be exercised at any time
through January 1, 2013 and provides that Inmarsat would make additional
spectrum available at an annual cost of $115 million (USD) per year. The
Phase 2 process is expected to take 30 months following the exercise by
LightSquared of the Phase 2 option.

About Inmarsat

Inmarsat plc (LSE: ISAT) is the leading provider of global mobile
satellite communications services. Since 1979, Inmarsat has been providing
reliable voice and high-speed data communications to governments, enterprises
and other organizations, with a range of services that can be used on land,
at sea or in the air. The company's services are delivered through a global
network of more than 400 distribution partners and service providers
operating in 100 countries. For the year ended 31 December 2009, Inmarsat plc
had total revenue of US$1,038.1m (2008: US$996.7m) with an EBITDA of
US$594.2m (2008: US$531.2m). For more information, please visit
www.inmarsat.com.

About LightSquared

LightSquared's mission is to revolutionize the U.S. wireless industry.
Through the creation of the first-ever wholesale-only nationwide 4G-LTE
network complemented by satellite coverage, LightSquared offers people the
speed, value, and reliability of universal broadband connectivity, wherever
they are in the United States. Through its wholesale-only business model,
those without their own wireless network or who have limited geographic
coverage or spectrum can develop and sell their own devices, applications,
and services using LightSquared's open 4G network–at a competitive cost and
without retail competition from LightSquared.

For further information about LightSquared, please go to
www.LightSquared.com.

    CONTACTS:       Amy Rosenberg              Tom Surface
                    Burson-Marsteller          LightSquared
                    Tel: +1-212-614-4558       Tel: +1-703-390-1579

Forward Looking Statement:

This release contains forward-looking statements and information
regarding LightSquared and its business. Such statements are based on the
current expectations and certain assumptions of LightSquared's management and
are, therefore, subject to certain risks and uncertainties. The
forward-looking statements expressed herein relate only to information as of
the date of this release. LightSquared has no obligation to update these
forward-looking statements to reflect events or circumstances after the date
of this release, nor is there any assurance that the plans or strategies
discussed in this release will not change.

Amy Rosenberg of Burson-Marsteller, +1-212-614-4558; or Tom Surface of LightSquared, +1-703-390-1579