Why military satellites matter.

• Author: Mazzei, James

(*) A debate about what should constitute the essential structure of the military's mobile communications satellites started in 1999. The debate is now entering a new chapter and history is repeating itself.

At issue is the next generation of the Navy's Mobile User Objective System (MUOS], a narrowbandtactical satellite communications system that is designed to improve secure voice, video and data services communications for U.S. forces on the move. MUOS provides a tenfold increase in transmission throughput over the current ultra high frequency (UHF) military satellite system. ManufacturerLockheed Martin Corp. has built five satellites so far.

In November 1999, a MUOS concept study was initiated and a number of architectures were evaluated. The one that appeared most practical to Navy acquisition officials was something akin to having the Defense Department become an anchor tenant on one of the commercial L-band systems, principally INMARSAT, Iridium or Globalstar.

But the program manager of the UHF Follow On (UFO) project, which was heading the study, thought differently. He argued that the risk of command-and-control communications interruptions - when forces might be under fire in dense foliage or in heavy rainstorms - demanded the use of the lowest possible satellite frequency. That frequency would have a larger corresponding wavelength, and the larger wavelength would be inhibited less by rain or by tree leaves.

The program manager proposed that the Navy build a satellite in the same frequency range as theUFO satellite system that was then being used. A vigorous debate ensued. With military UHF, the Navy would own the system and therefore be obligated to program the money up front. With L-band leases, the services could have a pay-as-you-go approach to mobile communications and avoid upfront costs. The decision was made to use military UHF.

A similar discussion is now unfolding with regard to a MUOS follow-on system. One aspect of thediscussion has changed to include not only where the money is spent but the question of whether the money be made available at all. In an environment of tight budgets, is a military satellite program simply too expensive?

These are decisions that have real-world implications for forces in the field that depend on timely and reliable communications. The realities of war are not functions of abstract considerations.

From the standpoint of physics, military UHF must be the preferred option to connect war...