Mexican telecommunications company Satmex's Solidaridad 1 satellite has been declared a loss after the back-up spacecraft control processor failed on 27 August. The primary processor failed in April last year.
Telemetry contact with the Hughes-built satellite was re-established almost immediately, but the processor did not respond to commands and the transponder payload was turned off. The 107 customers using the satellite for television, radio and pager services were transferred to Solidaridad 2 and Satmex 5 as well as the Telstar 5, 6 and 7 satellites operated by Loral.
Spacecraft control processor (SCP) failures have occurred in other HS-601-class satellites similar to Solidaridad 1. The failure of both processors resulted in the loss of PanAmSat's Galaxy 4 in May 1998, and three other HS-601s: DirecTV's DBS 1, Galaxy 7 and PanAmSat 4 suffered single SCP failures the same year.
Hughes traced the failures to tin-plated relay switches attached to the processors. Over time, these relays can grow tiny crystalline "whiskers" which can cause an electrical short in the SCP, resulting in blown fuses. The manufacturer switched to nickel relays in 1997, but Solidaridad 1 was built and launched in 1994.
Satmex had insured the satellite for $250 million, but has yet to decide how to proceed following the failure.
Source: Flight International