The Boeing Tracking and Data Relay Satellite (TDRS-I) has been stranded in an 8,000 x 35,800km (4,970 x 22,240 mile) transfer orbit following a problem with the craft's onboard propulsion system, which is designed to boost it into geostationary orbit.

The satellite was launched on 8 March and suffered the problem on 22 March. It is the second Boeing TDRS satellite to experience a malfunction in orbit. A third satellite, the TDRS-J, has been ordered. Boeing says it is "continuing orbit-raising manoeuvres and is confident that it can resolve this anomaly", indicating that the propulsion system was performing a series of shorter, low-thrust bursts. A loss of pressure has been found in one of the four propellant tanks on the Boeing 601 bus-based spacecraft. The TDRS-I propulsion system had successfully made three burns, raising the 247 x 29,135km orbit to 433 x 29,146km, then to 429 x 35,800km. This was raised to 3,521 x 35,789km on 19 March. The problem may have occurred on an aborted fourth propulsion burn. The TDRS-I's predecessor, the TDRS-H, experienced an antenna problem after launch in 2000. Meanwhile, Boeing plans to spend $100 million developing a smaller version of its 702 communications satellite platform, to fill the gap between the smaller 601 bus and large 702 craft, which has experienced a series of technical problems, damaging the reputation of the former Hughes Space and Communications business unit.


Source: Flight International