Glossary - R

Radio broadcasting
transmission of radio programmes intended for reception by the general public
(broadcasting)

Radio distribution
transmission of radio programmes (or parts of programmes such as news or advertising) from a central location for reception by local radio stations which then rebroadcast the transmissions, usually terrestrially
(broadcasting)

Radiation hardening
designing equipment (usually electronics) and materials to make them less susceptible to damage and spurious behaviour due to exposure to radiation (such as during spaceflight)
(technology)

Radio waves
a form of electromagnetic radiation with a frequency lower than 1 GHz
(physics)

Rain outage
loss of signal due to absorption and increased sky noise temperature caused by heavy rainfall
(communications)

Rake receiver
a receiver having a number of individual digital channels (called tines or fingers) which can combine these channels to form a stronger received signal
(technology)

Rapid Unscheduled Disassembly (RUD)
the unintended disintegration or explosion of a launch vehicle or spacecraft
(technology)

Red dwarf
a small, cool type of main sequence star
(astronomy, astrophysics)

Re-entry
the return of a spacecraft, through the Earth’s atmosphere, of a spacecraft originally launched from Earth
(spacecraft technology)

Reflection coefficient
numerical ratio of the reflected voltage to the incident voltage
(technology)

Registration
in a mobile satellite system the locating of a user terminal to determine which gateway should serve it
(satellite communications)

Regolith
a layer of unconsolidated, loose, heterogeneous material covering solid rock and created by weathering on planets with an atmosphere and by meteorite impact on planets, moons, asteroids and comets
(planetary science)

Repeater
signal path through a communications satellite payload which receives, amplifies and retransmits a channel; another name for repeater is transponder
(satellite communications)

Rideshare
a rocket launch shared between several spacecraft; the launch may be primarily for a large spacecraft along with several smaller rideshare secondary spacecraft, or may just be for several rideshare spacecraft; on a particular launch the rideshare spacecraft often have different owners
(launcher technology)