Lockheed Martin Space Systems of Sunnyvale, Calif., has delivered the first of a new generation of highly secure military communications satellites to Cape Canaveral Air Force Station, Fla., in preparation for a scheduled July 30 launch on an Atlas 5 rocket, the company announced May 24.

The Advanced Extremely High Frequency (AEHF) constellation will replace the U.S. Air Forceโ€™s Milstar communications satellites, over which the most sensitive and critical military signals travel. Lockheed Martin is under contract for three of the spacecraft, with a contract for the fourth satellite expected this summer, company officials have said.

AEHF was originally planned to be a constellation of three satellites, to be followed by the next-generation Transformational Satellite, or T-Sat, communications system. Cost estimates for T-Sat reached as high as $26 billion for the life of the program, and the Pentagon canceled it in 2009. The Air Force now plans to buy a total of six AEHF craft, some of which may incorporate some next-generation technologies developed under the T-Sat program.

The second and third AEHF satellites are planned to be launched eight and 16 months after the first craft.