Expanding communications: 'transformational' satellite price tag could reach $18B.

• Author: Peck, Michael

faced with a bandwidth crunch prompted in part by multiplying flocks of unmanned aerial vehicles that are transmitting multi-megabyte pictures, Defense Department planners are counting on a new generation of communications satellites to expand capacity.

A constellation of six transformational satellite or TSAT spacecraft, comprising five satellites and one in-orbit spare, currently are slated for launch around 2011, according to Christine Anderson, systems program director for the MILSATCOM joint project office in Los Angeles.

Lockheed Martin and Boeing won $472 million in risk reduction contracts. In 2006, the Air Force will select a single prime contractor to build the satellites. For the ground-based segment of the system, $3 million research contracts were awarded to Lockheed Martin, Raytheon and Northrop Grumman. This contact will be awarded in 2005.

If the laser-equipped TSATs are launched, they will combine the best features of the menagerie of radio frequency (RF) communications satellites in orbit or scheduled for launch.

Communications satellites come in three flavors: narrowband systems that are useful for voice transmissions but lack sufficient capacity for large data streams, wideband systems for sending large amounts of data, and protected satellites that are hardened against jamming and nuclear effects. By way of comparison, the current ultra high frequency follow on (UFO) narrowband satellites transmit at a rate of two to five megabits a second.

UFO's successor, MUOS (mobile user objective system), scheduled for launch in 2009, transmits at 40 megabits a second. TSAT will have 25 to 45 megabytes-per-second RF links to users on the ground, plus 20-gigabyte laser communications connecting the satellites to each other. Thus, they will combine the bandwidth of wideband systems such as the Wideband Gapfiller satellite, with the protected links of spacecraft, such as the advanced extremely high frequency (AEHF) satellites.

A 24-megabyte visual image transmitted by a reconnaissance aircraft, for example, would require two minutes to be transmitted to a current Milstar 2 satellite. A TSAT would cur transmission time to less than one second.

Particularly cutting-edge are the laser optics that will connect the geosynchronous TSAT satellites into an integrated network. If a signal is transmitted to a TSAT that is not within line-of-sight of the recipient, it forwards the message through a laser connection to another TSAT that has line...