SES World Skies personnel will be closely monitoring the path of Intelsat's "zombie" Galaxy 15 satellite this weekend to minimize any potential interference with SES's AMC-11, which handles distribution for dozens of cable networks in North America.
The Galaxy 15 spacecraft -- which stopped responding to ground controllers in early April -- is projected to be at AMC-11's assigned orbital location of 131 degrees West on Monday, May 31.
Sometime around midnight Eastern on Monday morning, AMC-11 and Galaxy 15 are expected to be at the same longitudinal position. At that point SES will execute a "leapfrog maneuver" for AMC-11, moving it from 0.3 degrees East to 0.3 degrees West of its nominal position at 131 degrees West, according to SES World Skies chief technology officer Alan Young.
"This is obviously not a routine effort," Young said. "We've had to shuffle things around. There's a large contingent of people working on this."
Cable networks delivered via AMC-11 include: The Weather Channel, Nick Jr., Nickelodeon West, MTV HD West, Bravo East, Lifetime, Showtime East, Hallmark Channel HD, C-SPAN, E! HD East, Food Network East, DIY Network, Great American Country, QVC, A&E East and West, History East and West, Military Channel, HD Theater, BBC America and Univision East.
Galaxy 15 is expected to drift out of AMC-11's orbital box by the following Monday, June 7.
SES staff will be monitoring the situation from Intelsat's teleport in Clarksburg, Md. For affected AMC-11 customers, Intelsat is providing "turnaround" services from four other SES satellites to AMC-11 via a 19-meter uplink tracking antenna.
In any case, the chance of an actual collision between the two satellites is statistically nil because they will never be less than 100 kilometers apart, according to Young. "There's no concern about a collision. But there is a concern about interference," he said.
As a contingency, SES World Skies also will maneuver the recently launched SES-1 to 0.3 degrees West of AMC-11's orbital position -- so that if there is interference from Galaxy 15 customers could cut over to SES-1.
SES has an animated representation showing the orbital manuevers it is planning to execute on its Web site, available here.
Scripps, which relies on AMC 11 to provide transmission service for all standard-definition versions of HGTV, Food Network, Travel Channel, DIY Network, Great American Country and Cooking Channel, which will debut on May 31, spoke about its own mitigation strategy.
"Scripps Networks' transmission engineers have worked closely with Intelsat, SES and other programmers to develop a comprehensive plan and take every action to avoid this potential interference," said Mark Hale, executive vice president and chief technology officer of Scripps Networks Interactive, the parent company of Scripps Networks. "We believe we have a sound strategy for mitigating the situation, and we are proactively reaching out to all of our distribution partners to provide the details of the transmission adjustments that must be made to maintain our programming signals without interruption."
Scripps' mitigation strategy involves increasing transponder sensitivity to create a greater transmit margin, between AMC-11 and Galaxy 15. Scripps has also established secondary feeds on AMC-1 and AMC-2, each of which are safe from the zone of interference, to be available to affiliates through June 8.
Intelsat's C-band Galaxy 15 was launched in October 2005 and had been expected to have remained in service until 2022. According to Intelsat, while initial reports suggested a solar storm disabled the satellite, "no definitive conclusions have been reached as to the actual source of the anomaly."
Intelsat in April moved customers from Galaxy 15 to Galaxy 12 with "minimal disruption" to services.