The Pentagon is reviewing options that include procuring an interim satellite and leasing more commercial services to deal with a potential gap in communications for troops on the move, according to military officials.

Concern about a gap in coverage between the U.S. Navy’s current UHF Follow-On (UFO) satellites and the next-generation Mobile User Objective System (MUOS) arose in June after the UFO F3 satellite, launched in June 1994, ceased operating , the officials said. The MUOS program is several years behind its original schedule.

Before the loss of that satellite, the Pentagon estimated there was a better than 70-percent likelihood that eight UFO satellites would still be operating beyond March 2010, when the first MUOS satellite is expected to enter service , according to U.S. Navy Capt. David Porter, program manager for Navy communications satellites at the Space and Naval Warfare Systems Command in San Diego.

Pentagon officials become concerned about a gap when the probability that it will have the minimum number of satellites required for a given service drops below 70 percent. With the loss of UFO F3, the calculated probability of having eight satellites on orbit drops below 70 percent by February 2009, Porter said in an Oct. 6 written response to questions.

The UFO constellation currently has nine operational satellites. The Congressional Budget Office recently said three of those satellites could stop functioning by 2008.

The last of the UFO satellites, all built by Boeing Satellite Development Center of El Segundo, Calif., was launched in December 2003.

A gap between the UFO and MUOS systems could be averted if the remaining UFO satellites last longer than expected, Porter said. Nevertheless , the Pentagon is considering holding a competition for an interim satellite , he said. Another option is asking MUOS prime contractor Lockheed Martin Space Systems of Sunnyvale, Calif., to build a gap-filler spacecraft that includes a UFO payload, Porter said. Accelerating the first MUOS launch is not an option, he said.

Porter declined to discuss cost estimates for those options, citing competition sensitivity.

Leasing commercial satellite services or relying on unmanned aerial vehicles to augment the UFO constellation also are possibilities, Porter said.

Meanwhile, Pentagon officials also are concerned about a potential gap in the Global Broadcast Service, a system that transmits maps, imagery, news programs and other bandwidth-intensive information to commanders in the field, according to Pentagon sources. The UFO constellation includes three satellites with Global Broadcast Service payloads, the last of which was launched in 1998.

The next Global Broadcast Service payload was scheduled to reach orbit in 2004 aboard the first Wideband Gapfiller communications satellite, but technical difficulties have delayed that launch until mid-2007. The satellite is not expected to become operational until it completes a planned six-month on-orbit checkout period, the sources said.

Leasing commercial bandwidth likely is the only option available for plugging a gap in the Global Broadcast Service coverage, the sources said.