Space Security 2011
2010 Development Software failure leaves Galaxy 15 adrift in the GEO belt, but it is eventually recovered On 4 April, Intelsat General’s Galaxy 15 communications satellite experienced a malfunction in GEO, which left it unresponsive to commands from ground operators.12 As a result, the satellite could not perform the station-keeping maneuvers required to maintain its orbital slot at 133W over the Pacific Ocean between Hawaii and South America. The gravitational forces from Earth’s bulge under the American landmass caused the satellite to slowly drift eastward through the active GEO belt and past other satellites. Throughout April, Intelsat sent over 200,000 commands to the satellite in an attempt to either turn off its communications payload or maneuver it to stop the drift.13 All attempts failed and, in early May, Intelsat announced that Galaxy 15 was too close to another active satellite, AMC 11, to attempt further interventions. Intelsat was concerned that the interventions would interfere with AMC 11. Galaxy 15’s communications payload was powered by the satellite’s solar panels. As long as the panels remained pointed at the Sun, the satellite had electrical power to retransmit any C-Band broadcasts it picked up. The satellite’s ability to keep its antennas pointed at the Earth and solar panels pointed at the Sun depended on the function of its momentum wheels. Without periodic commands from the ground, these momentum wheels would eventually saturate and the satellite would be unable to maintain its attitude pointing. Intelsat originally predicted this “loss of Earth lock” would happen in late July or early August.14 However, this estimate was revised repeatedly as time went on.15 On 29 December, Intelsat announced that it had regained full control of Galaxy 15.16 The satellite’s onboard battery had fully drained on 23 December, which caused the system to perform a software reset and restored ground control. The satellite was placed in safe mode, which prevented its payload from receiving or transmitting any signals. On 13 January 2011, Intelsat announced that it would be moving Galaxy 15 to an orbital slot at 93W for a full systems checkout.17 After that, the satellite could be put back into service in its original slot. On 20 April, Orbital Sciences, the company that built the satellite, suggested that the malfunction could have been caused by severe space weather.18 On the day of the failure, the U.S. National Oceanographic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center released a space weather advisory warning bulletin that detailed significant solar activity.19 However, on 13 January 2011, Intelsat announced that a failure review board had concluded that the malfunction was caused by an electrostatic discharge (ESD) event, and ruled out solar activity as the trigger.20 The ESD caused a software glitch, which resulted in the satellite’s inability to accept commands.
2010 Development Cataloged debris field from the 2007 intentional destruction of a Chinese satellite passes 3,000 objects In October, NASA announced that more than 3,000 pieces of trackable debris (>10 cm in diameter) from the intentional destruction of the Chinese Fengyun-1C weather satellite in January 2007 had been officially cataloged.21 In January 2011, four years after the event, more than 95 per cent of this debris was still in orbit, where much of it is expected to remain for several more decades.22 The debris from the destruction of the Fengyun-1C represents more than one-fifth of all cataloged objects below 2,000 km.23
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