Congressional budget reductions have forced the U.S. Air Force to defer integrated design work on its futuristic Transformational Satellite (T-Sat) Communications System, making the testing of key component technologies the main focus for this year, according to a senior program official.

Testing is under way on prototype hardware for the T-Sat laser-optical communications payload and Internet Protocol-based data processor-router, according to Brig. Gen. Ellen Pawlikowski, director of the Air Force-led Military Satellite Communications Program Office. The hardware was designed and built by the industry teams competing for the T-Sat space segment contract, she said.

Teams led by Lockheed Martin Space Systems of Sunnyvale, Calif., and Boeing Integrated Defense Systems of St. Louis are competing for the multibillion-dollar T-Sat contract.

Defense Department officials said it is premature to speculate on the total potential value of that contract. Press briefing documents released Feb. 6 with the Air Force’s 2007 budget request indicate that the service plans to spend a total of $9.8 billion on the T-Sat program from 2006 through 2011.

Last year, Congress slashed $400 million from the Air Force’s $836 million 2006 request for the T-Sat program, which is expected to go a long way toward quenching the military’s growing thirst for bandwidth. That budget cut forced the Air Force to move its target date for the first T-Sat launch from early 2013 to late 2014.

In addition , Congress roped off $120 million of the funds approved for T-Sat this year pending a report on the viability of slowing down the program and launching upgraded versions of the Advanced Extremely High Frequency (EHF) and Wideband Gapfiller satellites in the interim. The Air Force’s counterproposal, unveiled with its 2007 funding request, is to take an incremental approach to T-Sat technology deployment in which some of the more advanced capabilities envisioned for the system would be left off the first two satellites.

Pawlikowski said she studied the possibility of upgrading the Advanced EHF and Wideband Gapfiller satellites over the past six months, but decided to focus instead on a so-called spiral-development path for T-Sat. Upgrading the Advanced EHF and Wideband Gapfiller systems is feasible, but that strategy would be almost as expensive as the latest T-Sat plan, and the resulting satellites would be far less capable and be ready for launch only a year sooner than the initial T-Sat craft.

The less-aggressive T-Sat approach will open the door to the use of less complex, lighter components in the satellites, giving engineers more weight margin, Pawlikowski said. It also would allow the service to use less sophisticated software , thereby reducing program risk , she said.

One of the major technical challenges to T-Sat is its planned laser-optical communications payload, which would provide far greater capacity and speed than radio-frequency systems. But Air Force Undersecretary Ronald Sega said the technology is not so exotic, noting that laser-optical communications payloads have been the focus of multiple space demonstrations to date.

During a Feb. 14 briefing for reporters in his Pentagon office, Sega, a key proponent of the T-Sat spiral-development strategy, pointed to the Dec. 9 demonstration of two-way laser-optical communications between Japan’s Kirari and Europe’s Artemis spacecraft.

Laser communications also were successfully demonstrated in 2001 using the National Reconnaissance Office’s GeoLITE experiment, Sega said. During that experiment, the GeoLITE spacecraft exchanged data with another U.S. government spacecraft through laser cross-links.

The concept can be further refined and demonstrated in laboratories, a Defense Department official told reporters during a Feb. 6 briefing at the Pentagon.

Some of that work is going on right now with the T-Sat program. The Military Satellite Communications Program Office recently supervised the successful testing of prototype laser-communications hardware developed by Northrop Grumman and Lockheed Martin, who are competing as a team to build the T-Sat satellites, Pawlikowski noted. That testing was completed in early January at the Massachusetts Institute of Technology’s Lincoln Laboratory in Lexington, Mass.

These tests involved transmitting laser beams between two telescopes in laboratory conditions that simulate the distance between two geostationary-orbiting satellites, according to a Jan. 26 news release from the Air Force Space and Missile Systems Center in Los Angeles. The testing allowed the program office to assess the ability of Lockheed Martin’s design to acquire and track laser cross-link transmissions, according to the news release.

The Lincoln Laboratory is performing similar tests on Boeing’s prototype payload hardware, and those tests are scheduled to wrap up by the end of February, Pawlikowski said.

Also expected to undergo testing starting in 2006 is prototype hardware for T-Sat’s next-generation processor-router, Pawlikowski said. She likened this hardware to the “brains” of T-Sat, saying it will orchestrate the encryption, processing and transmission of data using Internet Protocol technology.

Lockheed Martin’s team is expected to complete testing of its prototype processor-router before the end of February , with the Boeing’s team scheduled to follow in April, Pawlikowski said.

Demonstrations of laser-payload and processor-router hardware that is “closer to flight-quality” are planned for later this year and next year, Pawlikowski said.

Meanwhile, despite postponing the T-Sat contract award, procurement of the ground segment is proceeding on schedule. The Air Force in January awarded Lockheed Martin Integrated Systems and Solutions of Gaithersburg, Md., a $2 billion contract to design and develop the T-Sat Mission Operations System, which will be used to manage the satellites’ operations and plug them into the Pentagon’s overarching communications network.

The advantage of awarding that contract first is that Lockheed Martin and Boeing can now focus their satellite design work on a single, known ground-segment concept, rather than planning for compatibility with any one of three competing ground-segment architectures, Pawlikowski said.