BATSAT (Teledesic T1)

BATSAT (Teledesic T1) [OSC]

The T1 satellite, previously passing under the pseudonym BATSAT (Broadband Advanced Technologies Satellite), is purely a demonstration satellite for the Teledesic constellation. The satellite is significantly different in size and design from the final constellation of 288 satellites. However, T1 will support two-way communications at speeds up to E1 rates. "This is a broadband satellite," he said.

T1 was placed in at low earth orbit at a 565-kilometer altitude via a Pegasus-XL air-launched booster, dropped from Orbital's Stargazer, L-1011 carrier aircraft. The satellite will become part of research already underway on the ground into software simulation and hardware development.

Key areas under scrutiny from Orbital's ground-control station in Dulles, Va., are atmospheric drag, radio frequency uplink and downlink power control, Ka-band atmospheric propagation delay, global positioning system synchronization analysis, laser-link stability, and sun and moon interference.

The payload was supplied by Boeing, with Orbital contributing its light-weight, low-cost MicroStar bus specifically designed for use with the Pegasus launcher. The MicroStar was scaled up by a factor of three for T1 from the standard model.

Teledesic and Boeing are keeping progress under wraps on the largest of their projects. They will not issue status reports on the experimental satellite, but confirmed that more demonstration "birds" will be launched in the coming months.

T1 is the first Ka-band satellite in orbit owned by a commercial enterprise, and one important area of testing will be frequency performance in the 28.6-GHz-to-29.1-GHz band. Teledesic officially won the right to Ka bandwidth frequencies last November after a long political struggle with rival satellite-communications consortia. Some analysts have questioned the downlink performance of such high frequencies during rainfall, however, saying Teledesic's rainfade margin will not be sufficient for users with small receiver dishes.