The first Advanced Extremely High Frequency (Advanced EHF) military communications satellite is now undergoing final thermal vacuum testing, Lockheed Martin Corp. [LMT] announced.

The second AEHF satellite completed thermal vacuum tests, Lockheed stated.

And the third spacecraft has been mated with the spacecraft core structure and the payload module. Preparations for the successful mate milestone were accomplished in one-third of the time needed for the previous AEHF satellite.

In vacuum testing, the satellite is stressed at the extreme hot and cold temperatures it will experience in space throughout its 14-year design life.

Following completion of spacecraft thermal vacuum testing, the team of prime contractor Lockheed Martin and Northrop Grumman Corp. [NOC] Space Technology, Redondo Beach, Calif., the payload supplier, will perform final integrated spacecraft and system test activities to prepare the vehicle for flight.

The first spacecraft is planned for delivery to the Air Force in early 2010 in preparation for launch aboard an Atlas V launch vehicle. The second and third Advanced EHF satellites are planned for launch in 2011 and 2012 respectively.

The Air Force AEHF system will provide global, highly secure, protected, survivable communications for all warfighters serving under the U.S. Department of Defense.

A single Advanced EHF satellite will provide greater total capacity than the entire Milstar constellation currently on-orbit. Individual user data rates will be five times improved. The higher data rates will permit transmission of tactical military communications, such as real-time video, battlefield maps and targeting data. In addition to its tactical mission, Advanced EHF will also provide the critical survivable, protected, and endurable communications to the National Command Authority including presidential conferencing in all levels of conflict.

Lockheed Martin is currently under contract to provide three Advanced EHF satellites and the Mission Control Segment to its customer, the Military Satellite Communications Systems Wing, located at the Space and Missile Systems Center, Los Angeles Air Force Base, Calif. The program is in the early stages of adding a fourth spacecraft to the planned constellation.