The 3192 kg (7031 lbm) satellite was built by Boeing Satellite Systems, using a BSS 601 satellite bus. The satellite carries S-, Ku- and Ka-band transponders. Each TDRS satellite can receive data rates at 300 megabits/second (Mbps) using Ku- and Ka-band, and 6 Mbps at S band. Each spacecraft carries the additional capability for Ka-band receive rates of up to 800 Mbps. Transmit data rates are 25 Mbps for Ku- and Ka-band, and 300 kilobits/second (Kbps) for S-band. In addition, the S-band phased array antenna can receive signals from five spacecraft at once, while transmitting to one. The TDRS satellites are unique in their ability to follow the motion of fast moving spacecraft, providing nearly continuous communication with controllers and researchers on Earth. In addition to the International Space Station (ISS) and Space Shuttle, other programs using the TDRS constellation include the Hubble Space Telescope, STARlink, the Tropical Rainfall Measuring Mission (TRMM), Landsat, and Earth Observing System (EOS). TDRS also provides expendable-launch-vehicle tracking services to launch service providers.