High frequency: Navy upbeat about communications spacecraft, despite radio troubles.

• Author: Erwin, Sandra I.
• Position: SPACE TECHNOLOGY

The Navy is building a dazzling satellite constellation that promises frontline troops and sailors at sea access to a multimedia wonderland.

But while the satellites are on a fast track toward a 2009 launch, the tactical radios that ground troops would need in order to receive the spacecraft's digital signals may not be ready on time.

The $6 billion mobile user objective system, or MUOS, is scheduled to replace aging ultra-high frequency communications satellites that, by information-age standards, are severely outdated. The new system will offer voice, data and video services.

Unlike other big-ticket space programs in the Defense Department, the MUOS spacecraft, military officials said, are on course to meet their launch deadlines and have not experienced cost overruns.

One unforeseen glitch, however, emerged in recent months, when program officials realized that the portable digital radio terminals that are required to receive the MUOS signals will be taking much longer than previously anticipated.

When the MUOS program got under way in 2004, the plan was for the terminals to be developed as part of the Defense Department's Joint Tactical Radio System. The JTRS program would deliver handheld and backpack-size radios, as well as larger terminals for ships and aircraft, that could be programmed to run the MUOS software. But JTRS has been derailed by a series of technical setbacks, budget cuts and Pentagon turf battles.

The Army--expected to be the largest user of MUOS communications services--earlier this year decided to curtail funds for the JTRS MUOS terminals, which effectively will delay the project by several years.

As a result, the JTRS program office published a solicitation in late May, that sought industry proposals for an "interim" radio that could be programmed to operate the MUOS waveform. Contractors were asked to submit "white papers" by June 4.

MUOS program officials at the Space and Naval Warfare Systems Command in San Diego said they are hopeful that the Army will be able to acquire new radios by the time the first MUOS satellite reaches orbit. Ground troops, including soldiers and Marines, account for 85 percent of the users of ultra-high frequency satellite communications.

While the Air Force oversees most of the Defense Department's space systems, the Navy is responsible for narrowband satellite communications. UHF is the only radio frequency that can penetrate clouds, foliage and urban structures.

The MUOS constellation...