In April, China launched its first tracking data relay satellite to lessen its dependency on ground satellite control and relay stations.

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Both spacecraft make use of the US space agency's Tracking and Data Relay Satellite System (TDRSS) to speak to the ground and controllers do not want any conflicts.

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The data are sent from the orbiting outpost to NASA's Tracking and Data Relay Satellites, which relay it to the satellite reception dishes at NASA's White Sands Test Facility in New Mexico.

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The primary computer that controls critical station functions defaulted to a backup computer, but it was not letting the station communicate with Nasa's Tracking and Data Relay Satellites, the US space agency said.

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