This C&P gives an update about the condition of EchoStar VIII. EB
* Operator: EchoStar
* Manufacturer: Space Systems/Loral
* Model: FS 1300
* Launched: 21 August 2002
* Orbit: Geostationary
SEU: EchoStar Corporation notified the U.S. Federal Communications Commission that the satellite incurred a single event upset (SEU) on 30 January 2011, which EchoStar believes was caused by increased space environment activity. The SEU caused the satellite to drift a few tenths of a degree west to 77.7 degrees West, outside of the 77 degrees West orbital cluster.
Upon learning of the drift, EchoStar executed braking maneuvers to stop the westerly drift and began a controlled drift of the satellite back to 77 degrees West.
EchoStar said it believes that the SEU did not cause any significant or permanent damage that will affect EchoStar 8's future operations.
Thrusters: During 2002, two of the thrusters on EchoStar VIII experienced anomalous events and are not currently in use. During March 2003, an additional thruster on EchoStar VIII experienced an anomalous event and is not currently in use. The satellite is equipped with a total of 12 thrusters that help control spacecraft location, attitude, and pointing and is currently operating using a combination of the other nine thrusters. This workaround requires more frequent maneuvers to maintain the satellite at its specified orbital location, which are less efficient and therefore result in accelerated fuel use. In addition, the workaround has resulted in certain gyroscopes being utilized for aggregate periods of time substantially in excess of their originally qualified limits. However, neither of these workarounds are expected to reduce the estimated design life of the satellite to less than 12 years. An investigation of the thruster anomalies, including the development of additional workarounds for long term operations, is continuing. None of these events has impacted commercial operation of the satellite to date.
Solar arrays: EchoStar VIII is equipped with two solar arrays which rotate continuously to maintain optimal exposure to the sun. During June and July 2003, EchoStar VIII experienced anomalies that temporarily halted rotation of one of the solar arrays. In December 2003 the other array experienced a similar anomaly. Both arrays are currently fully functional, but rotating in a mode recommended by the satellite manufacturer which allows full rotation but is different than the originally prescribed mode.
Battery: During September 2003, a single battery cell on EchoStar VIII exhibited reduced capacity. There are 72 battery cells on EchoStar VIII and all loads can be maintained for the full design life of the satellite with up to two battery cells fully failed. An investigation of the battery cell anomaly, which has not impacted commercial operation of the satellite, is underway.
EchoStar Annual Report 2003
Last modified: 08 February 2011
* Operator: EchoStar
* Manufacturer: Space Systems/Loral
* Model: FS 1300
* Launched: 21 August 2002
* Orbit: Geostationary
SEU: EchoStar Corporation notified the U.S. Federal Communications Commission that the satellite incurred a single event upset (SEU) on 30 January 2011, which EchoStar believes was caused by increased space environment activity. The SEU caused the satellite to drift a few tenths of a degree west to 77.7 degrees West, outside of the 77 degrees West orbital cluster.
Upon learning of the drift, EchoStar executed braking maneuvers to stop the westerly drift and began a controlled drift of the satellite back to 77 degrees West.
EchoStar said it believes that the SEU did not cause any significant or permanent damage that will affect EchoStar 8's future operations.
Thrusters: During 2002, two of the thrusters on EchoStar VIII experienced anomalous events and are not currently in use. During March 2003, an additional thruster on EchoStar VIII experienced an anomalous event and is not currently in use. The satellite is equipped with a total of 12 thrusters that help control spacecraft location, attitude, and pointing and is currently operating using a combination of the other nine thrusters. This workaround requires more frequent maneuvers to maintain the satellite at its specified orbital location, which are less efficient and therefore result in accelerated fuel use. In addition, the workaround has resulted in certain gyroscopes being utilized for aggregate periods of time substantially in excess of their originally qualified limits. However, neither of these workarounds are expected to reduce the estimated design life of the satellite to less than 12 years. An investigation of the thruster anomalies, including the development of additional workarounds for long term operations, is continuing. None of these events has impacted commercial operation of the satellite to date.
Solar arrays: EchoStar VIII is equipped with two solar arrays which rotate continuously to maintain optimal exposure to the sun. During June and July 2003, EchoStar VIII experienced anomalies that temporarily halted rotation of one of the solar arrays. In December 2003 the other array experienced a similar anomaly. Both arrays are currently fully functional, but rotating in a mode recommended by the satellite manufacturer which allows full rotation but is different than the originally prescribed mode.
Battery: During September 2003, a single battery cell on EchoStar VIII exhibited reduced capacity. There are 72 battery cells on EchoStar VIII and all loads can be maintained for the full design life of the satellite with up to two battery cells fully failed. An investigation of the battery cell anomaly, which has not impacted commercial operation of the satellite, is underway.
EchoStar Annual Report 2003
Last modified: 08 February 2011
