Glossary — C
19 terms
Control
The systems that execute steering commands by actuating effectors.
Example: The control loop responded to disturbances in milliseconds.
Control moment gyroscope
A spinning wheel on gimbals that provides large torque for attitude control.
Example: Control moment gyroscopes slew large space stations.
Cryogenic propellant
Propellant stored at very low temperatures, such as liquid hydrogen and liquid oxygen.
Example: Cryogenic propellant tanks need insulation and venting to manage boil-off.
Crewed mission
A mission carrying human astronauts.
Example: The crewed mission docked after a two-day transit.
Combustion chamber
The engine section where propellants mix and burn to produce hot gas.
Example: Regenerative cooling lines the combustion chamber wall to prevent melting.
Closed-loop control
Control that continuously compares output to a reference and corrects.
Example: Closed-loop control reacted to each guidance update.
Communications mission
A mission relaying voice, data, or broadcast signals.
Example: The communications mission beams television to millions.
Countdown
The sequence of checks and steps leading to launch.
Example: The countdown held at T-10 minutes for a readiness review.
Communications blackout
Loss of signal during reentry due to the plasma sheath.
Example: The capsule entered a communications blackout over the horizon.
CubeSat mission
A mission using small, standardized cube-shaped satellites.
Example: The CubeSat mission tested a novel propulsion system.
Crew rotation
A flight exchanging crew members on a space station.
Example: The crew rotation delivered four astronauts to the station.
Crossrange
The lateral distance a reentering vehicle can steer off its track.
Example: The vehicle's crossrange allowed it to reach alternate runways.
Command uplink
Sending instructions from the ground to a spacecraft.
Example: A command uplink triggered the software update.
Cryogenic loading
Loading very-low-temperature propellants just before launch.
Example: Cryogenic loading required frost-resistant connections.
Command and data handling
The subsystem that routes commands and processes telemetry.
Example: Command and data handling logged every subsystem state change.
Circularization burn
A burn at apogee or perigee that makes an elliptical orbit circular.
Example: The final GEO circularization burn occurred over the target longitude.
Commercial crew
Crew transport provided by private companies to a station.
Example: Commercial crew flights restored domestic astronaut launch.
CubeSat
A miniature satellite built to a standardized cube form factor.
Example: The CubeSat was deployed from the dispenser into orbit.
Control law
The mathematical rule mapping errors to actuator commands.
Example: The control law damped oscillations in pitch.