Contractor selection near for navy satellites.

The Navy is nearly ready to select a contractor for the mobile user objective system (MUOS), a constellation of ultra high frequency communications satellites designed to replace the current UFO (UHF Follow On) system.

The multibillion dollar contract will be awarded in late June to either Lockheed Martin or Raytheon.

Slated for launch in 2009 and full operational capability in 2013, MUOS will transmit at almost 40 megabits per second versus the two to five megabits of UFO, according to program manager Robert Tarleton, with the Navy's Space and Naval Warfare Systems Command.

MUOS and UFO are narrowband--less than 64 kilobits per second communications satellites that relay tactical UHF voice and low speed data communications, which have become increasingly crowded.

"Studies on UFO that were done a couple of years ago say that the UHF is 250 percent oversubscribed," said Tarleton. Operations in Iraq and Afghanistan have only worsened the bandwidth crunch.

Just as vital as MUOS's increased bandwidth is its ability to allow troops to communicate on the move. "UFO has been described as communications on the pod. If you're moving, you have to stop. You need directional antennae. With MUOS, we're expected to have the capability to get to a unidirectional antenna with the solder in the foxhole."

MUOS and UFO are part of a broad array of communications satellites operating all along the bandwidth spectrum. High-capacity satellites such as the Wideband Gapfiller handle megabyte-rich data streams such as photos transmitted by the soaring numbers of unmanned reconnaissance aircraft. Protected satellites such as the upcoming advanced extremely high frequency spacecraft have links hardened against jamming and nuclear effects.

Narrowband satellites lack the bandwidth to handle large amounts of data, and while their signals are encrypted, they are not proofed against jamming. "UHF does not have that requirement," said Tarleton. "Our only requirement is anti-jam command links so we don't lose the satellites."

But speed isn't everything. Laser communications, for example, are much faster as long as the beam isn't blocked by clouds. "Even though it's not the fastest throughput, over half of satcom users are on UHF," said Tarleton. "It's reliable. It gets through the weather."

Narrowband also has the advantage of being able to work with mobile terminals. While MUOS is designed to work with legacy UFO terminals, each of the services is responsible for designing and procuring their own terminals, which must be joint tactical radio system compliant.

"Estimates are that there are 18,000 to 30,000 UHF terminals are out in the field," Tarleton said. "There are so many that it's hard to get a good number."

MUOS is undergoing a review of its operational requirements. For now, the MUOS constellation tentatively will comprise five satellites plus an orbiting spare, compared to the eight satellites plus two spares of UFO. The MUOS contract will include "a significant amount of ground infrastructure needed for network management, telemetry and tracking and control," Tarleton said. The satellites are expected to ride to orbit on the Air Force's evolved expendable launch vehicle.

The maximum contract award is $6.2 billion, which includes replacement satellites, operating costs until 2023, and launch vehicles. "Unlike Air Force or Navy programs, our money for our launch vehicles also comes through the program office," Tarleton added.

Compared to the UFO systems, MUOS will offer both bandwidth and power. "This will be a lifesaver for users in difficult terrain such as jungle, who lack the signal strength to communicate with a UFO satellite," said Frank Rensselaer, who manages Raytheon's MUOS program.