EchoStar V

Summary: The satellite was originally designed with a minimum 12-year design life. Momentum wheel failures in prior years, together with relocation of the satellite between orbital locations, resulted in increased fuel consumption. These issues have not impacted commercial operation of the satellite, but have reduced the remaining spacecraft life to less than two years as of 30 June 2007.


Momentum wheels: In July 2001, EchoStar V experienced the loss of one of its three momentum wheels. Two momentum wheels are utilized during normal operations and a spare wheel was switched in at the time. A second momentum wheel experienced an anomaly in December 2003 and was switched out resulting in operation of the spacecraft in a modified mode utilizing thrusters to maintain spacecraft pointing. While this operating mode provides adequate performance, it results in an increase in fuel usage and a corresponding reduction of spacecraft life.


Thrusters: During August 2001, one of the thrusters on EchoStar V experienced an anomalous event resulting in a temporary interruption of service. The satellite was quickly restored to normal operations mode. The satellite is equipped with "a substantial number" of backup thrusters.


TWTAs: Unlike almost every other satellite operator, EchoStar even gives details about the health of its satellites' travelling-wave-tube amplifiers (TWTAs). Until 30 June 2001, two of them had to be replaced with spares. During the third quarter 2001, another TWTA "experienced unusually high telemetry readings and as a precaution, during September 2001 EchoStar substituted that TWTA with a spare."

EchoStar V is equipped with 48 TWTAs, including 16 spares.


Solar arrays: The satellite has a total of approximately 96 solar array strings. Prior to 2007, EchoStar V experienced anomalies resulting in the loss of seven solar array strings. In June 2007, the satellite lost an additional solar array string. The solar array anomalies have not impacted commercial operation of the satellite until mid-2007. Since the satellite only has a remaining life of less than two years, the solar array failures (which would normally have resulted in a reduction in the number of transponders to which power can be provided in later years), are not expected to reduce the current remaining life of the satellite.


Telemetry: During January 2003, EchoStar V experienced an anomaly in a spacecraft electronic component which affects the ability to receive telemetry from certain on-board equipment. Other methods of communication have been established to alleviate the effects of the failed component.

EchoStar SEC Filings

Last modified: 12 August 2007