Satmex’s Solidaridad HS 601 Fails

Satelites Mexicanos SA (Satmex) announced that Solidaridad I ceased transmitting on August 27 at 1545 UTC. Service was restored to most customers, other than rural school TV education programs by mid-week. The satellite carried signals for some 107 Mexican and international clients, accounting for US$20 million in annual income for Satmex.

Satmex began contingency operations immediately, providing space on Satmex V, Solidaridad II and Loral Skynet’s Telstar 5, 6 and 7 satellites, for all of the companies that were on Solidaridad I. Some users were able to move over quickly, but some were not prepared with their own contingency plans, such as pre-programmed antenna adjustments, to be able to move signals rapidly to another satellite. Most of the companies have contracts under which they do not pay if they receive no service, most of them do not have provisions regarding restoration of service. The failure of the satellite caused problems with automatic bank tellers, credit card verification services, radio and television stations, beepers, and rural telephone operations.

The failure stopped television service for 12,000 mostly rural secondary schools across Mexico that depend on satellite signals for some or all of their teaching. It will take technicians three weeks to restore service to some of the schools, whose antennas must be reoriented to capture signals from other satellites. The missed classes will be rebroadcast at a later date.

Mexico City’s newspaper El Universal reported that the satellite failure had knocked out service to 50 subscribers of its news service. El Universal turned to the internet to distribute its news in place of the satellite. The satellite's customers also included 28 companies, primarily in the television and radio broadcasting and telecommunications businesses, about half of which are Mexican companies.

Mexico's 17,000 bank branches reported no problems, as operations were switched last year to the Solidaridad 2, and to a digital network operated by Telefonos de Mexico SA. Last year's satellite shutdown affected financial transactions throughout Mexico, prompting banks to switch to back up networks and move communications to a newer satellite.

Satmex made 65 attempts to reestablish communication with the central processors of the satellite. Technicians from Hughes recommended the satellite's operations be terminated based on the loss of electric energy stored in the batteries at reaching their minimal acceptable level. The satellite was switched off at 2335 UTC August 29. Ninety four percent of users who represented 86 percent of utilized capacity have had their services restored or have been assigned available satellite space. 

Satmex indicated the failure could have been caused by a short circuit in the back-up computer. Although the Solidaridad I failure is still being investigated, an earlier HS 601 processor defect could be the problem. The previous failure resulted from electrical shorts caused by internal tin-plated relay latching switches that act as on/off switches within the Spacecraft Control Processor. Hughes found that under certain conditions, a tiny, crystalline structure, less than the width of a hair, can grow and bridge a relay terminal to its case, causing an electrical short. Hughes is now using nickel-plated switches and improved processes, which appear to have corrected the processor defect on newer satellites. Engineers are currently studying data received from Solidaridad I to determine if the failure occurred in a similar fashion to previously recorded incidents.

Solidaridad I, a Hughes built HS 601, was launched November 20, 1993 and was designed to operate until 2006 or 2007, at a cost of US$250 million (which includes manufacture, launch and insurance). The satellite was already running on a back-up computer, after its main computer failed permanently in April 2000. The satellite also had a major technical problem in May 1999. Income from the satellite was not insured. It is expected it will take about 30 months for Satmex to get a replacement satellite into orbit.

  

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