SES prepares for ‘zombie sat’ orbital manoeuvres

SES World Skies is set to carry out an intricate set of orbital manoeuvres aimed at steering its AMC-11 satellite clear of interference from Intelsat’s Galaxy-15 spacecraft, which became unresponsive and is on the verge of drifting into the SES…

SES World Skies is set to carry out an intricate set of orbital manoeuvres aimed at steering its AMC-11 satellite clear of interference from Intelsat’s Galaxy-15 spacecraft, which became unresponsive and is on the verge of drifting into the SES satellite’s orbital slot.

As the stray satellite nears AMC-11’s orbital location at 131W, SES plans to have AMC-11 match the eastward drift of Galaxy-15 in order to maintain a minimum separation between the two satellites. This synchronised drift is designed to protect AMC-11 services from any interference that could be caused by Galaxy-15. Both satellite broadcast on the same frequencies.

At the same time, SES World Skies will move its new SES-1 satellite to the opposite side of Galaxy-15, thereby enabling some customers, including cable television networks, to leapfrog their broadcasts over the potential interference that could be caused by the wandering spacecraft. Customers will either be able to maintain services on AMC-11 during its drift, or repoint antennas to SES-1 in order to best protect their services.

Among the customers that use AMC-11 are Cablevision, Comcast and Time Warner, all of whom have stated that Galaxy-15 will not interfere with their broadcasts.

SES estimates that the risk of interference will end on June 7 when Galaxy-15 exits the area about 22,000 miles above the earth’s surface. Galaxy-15 is then expected to power down by August 2010.

Galaxy 15 experienced an anomaly in April 5 following a solar storm which left Intelsat unable to direct the control of the spacecraft, which provided transmission capacity for cable programmers over North America from the 133W orbital slot.