Glossary — R
22 terms
Rendezvous
The maneuver that brings two spacecraft into close proximity.
Example: The resupply craft performed a rendezvous with the station.
Rocket
A vehicle propelled by expelling mass, used to reach space.
Example: The rocket climbed away from the launch site.
Reentry
The return of a spacecraft through the atmosphere to Earth's surface.
Example: Reentry heating raised the capsule's surface to extreme temperatures.
Reaction wheel
A spinning flywheel used to rotate a spacecraft by conservation of angular momentum.
Example: Reaction wheels point the spacecraft without expending propellant.
Rover
A wheeled vehicle that traverses a planetary surface.
Example: The rover drilled into the regolith to collect samples.
Roll
Rotation about a vehicle's longitudinal axis.
Example: Roll stabilized the vehicle on its flight azimuth.
Radiator
A surface that rejects waste heat into space by thermal radiation.
Example: Radiators keep the electronics within thermal limits.
Resupply mission
A flight delivering supplies, equipment, or fuel to a destination.
Example: The resupply mission delivered oxygen and water to the station.
Regenerative cooling
Circulating fuel through chamber walls to absorb heat before combustion.
Example: Regenerative cooling keeps the nozzle from melting during the burn.
Reconnaissance mission
A mission collecting intelligence or surveillance imagery.
Example: The reconnaissance mission imaged the region in high resolution.
RAAN
Right Ascension of the Ascending Node: the angle from the vernal equinox to the ascending node, fixing an orbit's orientation in space.
Example: Sun-synchronous orbits require a specific RAAN to hold their lighting.
RCS
Reaction Control System: small thrusters that provide attitude control and small translations.
Example: The reaction control system fired to hold the vehicle's orientation.
Rate gyro
A gyroscope measuring angular rate about an axis.
Example: Rate gyros sensed roll during reentry.
Range
The area and associated infrastructure used to conduct launch operations.
Example: The range issued a no-go for the boat in the hazard zone.
Reentry mission
A flight returning a spacecraft through the atmosphere.
Example: The reentry mission splashed down in the Pacific.
Range safety
The discipline of ensuring public safety during launch.
Example: Range safety monitors tracked the vehicle in real time.
Restart
The ability of an engine to be reignited after shutdown.
Example: Upper stages need restart capability for multi-burn missions.
Redundancy
Duplicating critical systems to tolerate failures.
Example: Triple redundancy protected the flight computer.
Roll program
The early maneuver orienting the vehicle onto its flight azimuth.
Example: The vehicle began its roll program shortly after clearing the tower.
Robotic arm
A mechanical limb on a spacecraft used to grapple and move objects.
Example: The robotic arm captured the visiting cargo vehicle.
Reusability
The capability to recover and fly a rocket or stage again.
Example: Reusability has dramatically lowered launch costs.
Recovery
Retrieving a landed booster or capsule after flight.
Example: Recovery crews towed the capsule to the ship.