WASHINGTON — Facing a looming gap in its mobile satellite communications coverage, the U.S. Navy plans to tap a new service developed by commercial provider Iridium Communications LLC as it waits for its next-generation constellation to come on line.

The Defense Information Systems Agency (DISA), which buys commercial satellite capacity on behalf of Pentagon users, plans to spend about $20 million this year on the Netted Iridium service, Bruce Bennett, DISA’s director of satellite communications, teleports and services, said in a Dec. 14 interview. DISA spent about $70 million on Iridium mobile satellite services in 2009, and the total amount should increase to about $80 million this year with the addition of the Netted Iridium service, he said.

The Navy today relies on its UHF Follow-On satellites — the last of which launched in 2003 — and leased capacity on older satellites for so-called narrow-band communications capacity. Several of the UHF Follow-On satellites failed earlier than expected, and others are operating on backup systems and could fail without warning. Even if no further failures occur, the UHF Follow-On system could degrade to an unacceptable level of performance by May 2010, government documents show.

Meanwhile, the Navy’s next-generation Mobile User Objective System (MUOS) continues to hit development snags, and the launch of the first satellite in the series has slipped to early 2011.

In 2008, the Navy began looking for opportunities to fly a UHF payload on a commercial satellite, but that idea was scrapped last year when it became clear that a commercial solution could not be operational until around 2012. Instead, the Navy has turned to Netted Iridium, a retooled variant of the traditional Iridium service the military has used for years.

Until recently, Iridium’s constellation of 66 low-orbiting satellites had only supported point-to-point telephony. The Netted Iridium service will enable mobile warfighters, primarily in Afghanistan, to broadcast voice or data signals via satellite to multiple users simultaneously. It will also connect much faster than the standard Iridium service, said Scott Scheimreif, vice president of government programs at Bethesda, Md.-based Iridium Communications.

“It’s acting as a bridge,” Bennett said. “We don’t have a MUOS system yet. If we had one, and it was up and operational and we had handsets for it, the need for Netted Iridium may not exist. This is a fairly inexpensive way to fill that void.

“All the other alternatives require us to build, launch and support them and develop handsets for them. Even at the most rapid urgency, that’s 36 months. That’s really not going to be any benefit to the guys in Afghanistan. What we’re doing with Netted Iridium, we’re deploying in three to six months.”

The Netted Iridium radios are built by NexGen Communications LLC of Dulles, Va., a subsidiary of ITT Corp. The company has built about 500 Netted Iridium radios that are being deployed to Afghanistan following an urgent-need request from U.S. Central Command to senior Pentagon brass. NexGen Communications in November was awarded a $9.7 million Navy contract to deliver 1,450 more Netted Iridium radios by March.

Meanwhile, the U.S. government continues to rely on commercial satellite operators to provide for the majority of its satellite connectivity around the world. DISA spent a total of around $400 million on commercial satellite communications services in 2009, up from about $350 million the year before, Bennett said. As new terminals and upgrade kits continue to be deployed, DISA is also beginning to use commercial bands it has not used extensively in the past.

While Ku-band terminals are the most widely deployed commercially, satellite operators are increasingly deploying Ka-band capacity, Bennett noted, adding that DISA’s use of commercial X-band capacity will grow this year. DISA bought the equivalent of two commercial X-band transponders in 2009, and Bennett expects that amount to roughly triple in 2010. The two likely beneficiaries of this increase are Xtar LLC of Rockville, Md., which operates one dedicated X-band satellite and leases capacity on another, and Paradigm Secure Communications of the United Kingdom, which offers the X-band services of its Skynet satellite fleet through U.S. partner CapRock Communications of Houston.

Big changes also are coming for the way DISA buys satellite communications capacity. Most capacity for the military is now purchased through a vehicle called the Defense Satellite Transmission Services-Global contract, which relies on companies known as integrators to buy capacity from satellite operators and resell it to the government. A new contracting vehicle called the Future Comsatcom Services Acquisition will allow the government far greater flexibility in its contracting. For example, if the government has a simple commercial bandwidth requirement and does not need any additional networking services, it will be able to contract directly with a satellite operator such as Intelsat or SES for that bandwidth, which the current contract does not allow.

“Our requirements are changing so fast, I really can’t tell you what they will look like two years from now,” Bennett said. “I will now have a vehicle in place where I can lease anything from a megabit to a whole satellite.”

The final request for proposals for the Future Comsatcom Services Acquisition is expected in the spring, with contracts expected to be awarded late in the year.