The U.S. Air Force has begun design work on a pair of satellite payloads that will launch around 2013 or 2014 to provide secure communications to U.S. forces — primarily Navy ships and submarines — operating in extreme northern latitudes.

The extremely high frequency (EHF) payloads are to be hosted aboard unspecified satellites operating in polar orbits and will be interoperable with terminals designed for the Advanced EHF and Transformational Satellite (T-Sat) communications systems under development by the Air Force, according to service and industry officials. The Advanced EHF and T-Sat systems are slated to begin launching in 2008 and 2014, respectively.

Like the Air Force’s current Milstar secure communications satellites, the Advanced EHF and T-Sat satellite systems will operate in geostationary orbit, which is ill-suited for covering the world’s extreme northern and southern latitudes. U.S. submarines, particularly those carrying missiles tipped with nuclear warheads, often operate in far-northern waters.

Continuity of service is the top priority as the Air Force embarks on the Enhanced Polar System program, said Air Force Brig. Gen. Ellen Pawlikowski, director of the military satellite communications joint program office at the Air Force Space and Missile Systems Center in Los Angeles. She said having two such payloads in orbit will provide 24-hour-a-day coverage in the world’s northernmost regions.

With a 2006 budget of $8 million for the Enhanced Polar System, the Air Force awarded study contracts for the payload April 28 to Boeing Integrated Defense Systems of St. Louis and Northrop Grumman Space Technology of Redondo Beach, Calif. Under the six-month contracts, worth $1.5 million each, the companies will design communications payloads whose signals are difficult to detect, jam and intercept and would serve forces operating above 65 degrees north latitude.

“This study contract represents the first step in defining a robust and secure satellite payload needed for Extremely High Frequency communications for Air Force and Navy warfighters in remote regions of the world,” Michael Gianelli, Boeing vice president of navigation and communications systems, said in a press release July 6.

Boeing and Northrop Grumman both supplied payloads for the Air Force’s Milstar satellite system. Boeing also supplied three payloads for the Interim Polar Satellite program, formerly known as the Milstar Polar Adjunct. These payloads are based on the Milstar-compatible EHF payloads that are included on the Navy’s Boeing-built Ultra High Frequency Follow-On system, a constellation of geostationary satellites that provide communications links to ships at sea and to mobile ground forces in remote regions of the world.

The Interim Polar Satellite payloads are hosted by classified satellites operating in polar or near-polar orbit. The first satellite carrying such a payload was launched in 1998, according to the ” Aeronautics and Space Report of the President FY 98,” which is posted online at NASA’s Web site.

According to documents submitted to Congress in February with the Air Force’s 2007 budget request, the second Interim Polar payload is slated for availability in 2006, with the third becoming available in 2007.

In the press release, Gianelli said Boeing’s experience with digital signal processing technology and the legacy Interim Polar Satellite program positioned the company for work on the Enhanced Polar System.

Boeing spokesman Dave Garlick referred questions for this story to Air Force Space and Missile Systems Center, which did not respond by press time to follow up questions.

The Enhanced Polar System payloads need not be as powerful or complex as those planned for the T-Sat satellites because the user base is much smaller, Pawlikowski said in a June 20 interview.

Bill Harding, program manager for protected communications in the military satellite communications office, said during the June 20 interview that the Enhanced Polar System will primarily serve “strategic requirements.”

Boeing and Northrop Grumman are competing for work on the T-Sat program, with Boeing angling for the prime contract and Northrop serving as payload provider to a Lockheed Martin-led team. Northrop Grumman is supplying the payloads for the Advanced EHF satellites, which are being built by Lockheed Martin Space Systems of Sunnyvale, Calif.

Stuart Linsky, Northrop Grumman vice president for satellite communications, said in a written statement that the company is leveraging its work on the Advanced EHF payloads as it develops its concept for the Enhanced Polar System.

Boeing’s press release said the company’s study contract includes a 14-month Phase 2 option, worth $8 million, that “would include delivery of a completed system architecture, a system engineering master plan and a final risk management plan.”

The Air Force has requested $35 million for the Enhanced Polar System program for 2007. The House and Senate armed services panels, as well as the House Appropriations Committee, have approved that amount in their respective Pentagon oversight and spending bills for 2007. The Senate Appropriations Committee has yet to mark up its version of the defense spending bill.

Comments: jsinger@space.com