Yohkoh

Telecommunications Description

The telemetry subsystem consists of an S-band transmitter capable of transmitting realtime pulse code modulation data and a range measurement signal simultaneously as well as data dumped from the onboard recorder. There is also an x-band transmitter which is used with Japanese ground stations. The telemetry frequency is 2256.22 MHz. Mission control is performed at the ISAS Kagoshima Space Center, which also provides the facilities for spacecraft command and telemetry. The Sagamihara Space Operations Center (SSOC) provides communications support and interface to the JPL Network Operations Control Center for DSN support. The prime tracking and data acquisition station is at Kagoshima (131 deg E. Long., 31 deg N. Lat.) which is in contact with the spacecraft for 5 consecutive orbits per day. Contact duration is approximately 10 minutes, during which realtime and/or stored commands are relayed to the spacecraft and realtime and playback telemetry data are received. The NASA DSN provides data acquisition contacts via Goldstone, Madrid and Canberra, with up to ten DSN station contacts per day, for a period of three years. All telemetry data from the DSN are transmitted non-realtime to the ISAS SSOC via existing 56 kbps data lines. Approximately 50 Mbytes of data are returned per day.