Glossary — T
28 terms
Thrust
The force produced by a rocket engine by expelling mass at high velocity.
Example: The first stage develops over seven hundred kilonewtons of thrust at liftoff.
Transporter erector
The machine that moves a rocket to the pad and raises it vertical.
Example: The transporter erector rolled the rocket to the pad upright.
Thermal control system
The systems that regulate a spacecraft's temperature within safe bounds.
Example: The thermal control system uses blankets, radiators, and heaters.
Thermal protection system
The integrated materials shielding a vehicle from entry heating.
Example: The thermal protection system was inspected for damage post-flight.
Trajectory
The path a vehicle follows through space and time.
Example: The trajectory was tweaked to hit the planned orbit.
Turbopump
A pump driven by a turbine that feeds propellant into the engine at high pressure.
Example: The turbopump spins tens of thousands of revolutions per minute.
Trajectory optimization
Computing the best path that meets constraints and minimizes cost.
Example: Trajectory optimization shaved propellant from the ascent.
T-0
The designed moment of liftoff in a countdown.
Example: All conditions were met as the clock reached T-0.
Thrust vector control
Steering a vehicle by angling its engine thrust.
Example: Thrust vector control provided pitch and yaw authority.
Technology demonstration
A mission testing new hardware or techniques in space.
Example: The technology demonstration proved laser communications.
Transponder
A device that receives, amplifies, and retransmits a signal.
Example: The transponder relayed uplink commands back as telemetry.
TLE
Two-Line Element set: a standard two-line format encoding a satellite's orbital elements for propagation.
Example: Tracking software ingests the latest TLE to predict a pass.
Transceiver
A unit that both transmits and receives communications signals.
Example: The radio transceiver handled both uplink and downlink.
Throttling
Adjusting engine thrust level during flight.
Example: The booster throttled down for maximum dynamic pressure.
Telemetry
The automated transmission of onboard data to the ground.
Example: Telemetry showed nominal temperatures after separation.
Thruster
A small engine used for attitude control and maneuvering.
Example: Thrusters fired to correct the spacecraft's drift.
Thrust-to-weight ratio
The ratio of engine thrust to vehicle weight, indicating launch capability.
Example: A thrust-to-weight ratio above one is needed to lift off.
Terminal guidance
The final phase of steering near a target or landing.
Example: Terminal guidance homed the lander onto the pad.
Total impulse
The integral of thrust over the full burn time.
Example: A booster's total impulse determines the energy it imparts to the stack.
Tundra orbit
A high-inclination geosynchronous orbit with high eccentricity over high latitudes.
Example: A Tundra orbit provides nearly stationary coverage over one hemisphere.
Terminal countdown
The final minutes of a countdown executed by an automated sequencer.
Example: The terminal countdown proceeded automatically after T-10 minutes.
Touchdown
The moment a returning vehicle contacts the ground or water.
Example: Touchdown was gentle, and recovery boats headed out.
Tether
A cable connecting two space objects for dynamics, power, or stability.
Example: An electrodynamic tether could generate drag or power in orbit.
Thermosphere
The atmospheric layer where temperature rises and the ISS orbits.
Example: The thermosphere hosts most low Earth orbit satellites.
Target vector
The desired state a guidance system drives the vehicle toward.
Example: The target vector pointed the vehicle toward its orbit.
Troposphere
The lowest atmospheric layer where weather occurs.
Example: Most clouds and storms live in the troposphere.
Turnaround
The process of refurbishing and preparing a vehicle for its next flight.
Example: Rapid turnaround shrank the interval between flights.
Terminal velocity
The constant speed where gravity balances atmospheric drag.
Example: The falling stage reached terminal velocity before the chute opened.