Space and Solar Definitions - T
TAU - Thousand AU Mission.
TCM - Trajectory Correction Maneuver, spacecraft propulsive maneuver.
TDM - Time-division multiplexing.
Termination shock - Shock at which the solar wind is thought to slow to subsonic speed, well inside the heleopause.
Terrestrial planet - One of the four inner Earth-like planets.
Three-way - Coherent communications mode wherein a DSS receives a downlink whose frequency is based upon the frequency of an uplink provided by another DSS.
THz - Terahertz (1012 Hz).
TLM - DSN Telemetry System. Also, telemetry data.
TMOD - PL's Telecommunications and Mission Operations Directorate.
TOS - Transfer Orbit Stage, upper stage.
Transducer - Device for changing one kind of energy into another, typically from heat, position, or pressure into a varying electrical voltage or vice-versa, such as a microphone or speaker.
Transponder - Electronic device which combines a transmitter and a receiver.
TRC - NASA's Teacher Resource Centers. Obsolete, now called Educator Resource Centers, ERC.
TRK - DSN Tracking System. Also, Tracking data.
TRM - Transmission Time, UTC Earth time of uplink.
True anomaly - The angular distance of a point in an orbit past the point of periapsis, measured in degrees.
TWNC - Two-Way Non-Coherent mode, in which a spacecraft's downlink is not based upon a received uplink from DSN.
Two-Ribbon Flare - A flare that has developed as a pair of bright strands (ribbons) on both sides of the main inversion ("neutral") line of the magnetic field of the active region.
Two-way - Communications mode consisting of downlink received from a spacecraft while uplink is being received at the spacecraft. See also coherent.
TWT - Traveling Wave Tube, downlink power amplifier in a spacecraft telecommunications subsystem, the final stage of amplification for downlink (same unit as TWTA).
TWTA - Traveling Wave Tube Amplifier, downlink power amplifier in a spacecraft telecommunications subsystem, the final stage of amplification for downlink (same unit as TWT).
TXR - DSN's DSCC Transmitter assembly.
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