All partner nations are now using the Advanced Extremely High Frequency (AEHF) protected communications satellite system after the United Kingdom connected earlier this year. Four nations will use the Lockheed Martin-produced satellites for their most important transmissions, from commanders-in-chief to troops in the field.

The U.K. connection follows Canada's first successful call in May, 2013, and The Netherlands' initial connection came two months later. Over the past year AEHF facilitated many connections between international users, and U.S.-led tests in April included all four partners.

"AEHF is a keystone in global security. It is the only system that can provide highly-protected communications, circumventing our adversaries' jammers in most wartime operations," said Mark Calassa, vice president of Protected Communication Systems at Lockheed Martin.

"We are committed to driving this capability forward. All four partners are connected, and we are marching steadily toward Multi-Service Operational Test and Evaluation."

U.K. armed forces started to connect over the course of several weeks beginning Feb. 25. They used two terminal variants to communicate with AEHF-2: One made for connections on land and another designed for users at sea. Service members contacted the satellite at Colerne Airfield, Wiltshire, with the shore variant of the Navy Multiband Terminal (NMT). In separate tests, U.K. users connected via the NMT ship variant from Telemetry and Command Station Oakhanger, Hampshire.

"AEHF not only delivers higher-bandwidth communications for the U.K., it makes communications with allies faster and easier," Calassa said.

"AEHF is showing it can handle the demands of protected coalition communications at high speeds, connecting nations with their own users and allied users across the globe."

The four-nation AEHF program is led by the U.S. Air Force Space and Missile Systems Center at Los Angeles Air Force Base, California. Lockheed Martin is under contract to deliver the Mission Control Segment and six AEHF satellites, which are assembled at the company's Sunnyvale, California, facility.