Landsat 4 was able to resume science operations when the Tracking and Data Relay Satellite System (TDRS) came online, then was placed in standby in January 1986. Landsat 4 was brought back online to provide international coverage in 1987, when Landsat 5 lost its TDRS link, and thus the ability to image areas beyond line of sight to a ground station, and continued to do so until it, too, lost its TDRS link in 1993, ending science data return. Landsat 4 continued to broadcast telemetry, tracking, and command data, which was transmitted on the still-functional S-band, until the satellite was decommissioned June 15, 2001.