Aug 27 2000
From The Space Library
In the second on-orbit failure of Hughes Electronic Corporation's HS601-model satellite, the Spacecraft Control Processor (SCP) of Mexico's Solidaridad I communications satellite malfunctioned, disrupting television, radio, and pager services. The first incident had occurred on the Galaxy IV satellite, causing similar communications disruptions in the United States during 1998. In the current malfunction, operators in Iztapalapa and Hermosillo received a series of alarms indicating that the only functioning SCP on board the Satmex-owned craft had turned itself off. The satellite had two SCPs on board and needed only one to carry out its communications relay properly, but Solidaridad I already was running on its backup SCP, having lost its first processor a year ago. Engineers suspected that the cause of the incident was the growth of a tiny crystalline structure that leads to electrical shorts. Hughes investigators had identified this type of malfunction in their satellites containing tin-plated relay switches and, therefore, had begun to use nickel-plated switches in new satellites to prevent future occurrences of such electrical shorts. However, Solidaridad I, designed for 14 years of service in space, had launched in 1993 before the conversion to nickel-plated switches. The Solidaridad series, comprising two satellites, provided service to all of Mexico, also extending to the southwestern United States, the Caribbean, and Central and South America. The malfunction led to the loss of educational television programming in 12,000 schools in Mexico, mostly in remote rural areas where some students rely entirely on televised courses. Satmex was transferring Solidaridad I users to the three other satellites in its fleet.
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