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GIOVE (satellites)
GIOVE, short for Galileo In-Orbit Validation Element, was a pair of ESA experimental satellites launched in 2005 and 2008 to secure Galileo's frequencies and test its atomic clocks.
GIRD-09
GIRD-09 (ГИРД-09), also called rocket 09, was the first Soviet rocket to fly on liquid propellant, launched on 17 August 1933 near Moscow; modern sources classify it as a hybrid rocket.
Global Positioning System
The Global Positioning System (GPS) is a US satellite navigation system providing position and time worldwide, operated by the Space Force and fully operational since 1993.
Globalsat Group
Globalsat Group, also known as Globalsat, is a Pan-American mobile and fixed satellite services consortium founded in 1999 in Bolivia and headquartered in Boca Raton, Florida.
Globalstar
Globalstar is an American satellite telecommunications company headquartered in Covington, Louisiana, providing mobile satellite and IoT services from a low Earth orbit constellation that has carried Apple's Emergency SOS via satellite since 2022.
GLONASS (Глобальная навигационная спутниковая система)
GLONASS, or ГЛОНАСС, is Russia's global navigation satellite system, operated by the Russian Ministry of Defense as a counterpart to GPS and restored to 24 satellites in 2011.
GLONASS-K (ГЛОНАСС-К)
GLONASS-K (ГЛОНАСС-К), also designated Uragan-K, is a third-generation Russian navigation satellite built by ISS Reshetnev for GLONASS, first launched in 2011. It introduced an L3 CDMA civil signal and a COSPAS-SARSAT search-and-rescue payload.
GNSS augmentation
GNSS augmentation is the family of systems and techniques that improve the accuracy, integrity, and availability of satellite navigation such as GPS, chiefly through satellite-based and ground-based correction systems.
GOCE
GOCE, the Gravity field and steady-state Ocean Circulation Explorer, was a European Space Agency satellite launched in 2009 that measured Earth's gravity field and mapped the geoid.
GOES
GOES (Geostationary Operational Environmental Satellite) is a series of NOAA weather satellites parked in geostationary orbit, providing continuous imagery, lightning mapping, and space weather monitoring of the Western Hemisphere since 1975.
GOLD (instrument)
GOLD (Global-scale Observations of the Limb and Disk) is a NASA far-ultraviolet imaging spectrograph launched in 2018 on a commercial communications satellite to study Earth's upper atmosphere.
Goldstone Deep Space Communications Complex
The Goldstone Deep Space Communications Complex is a NASA satellite tracking facility in California's Mojave Desert, the US station of the Deep Space Network, managed by the Jet Propulsion Laboratory.
Google Lunar X Prize
The Google Lunar X Prize (GLXP) was a $30 million competition, funded by Google and launched in 2007, challenging private teams to land robotic spacecraft on the Moon.
Gordon Cooper
Leroy Gordon Cooper Jr., known as Gordo, was an American Air Force officer and NASA astronaut, one of the original seven Mercury astronauts selected in 1959.
Gorizont
Gorizont (Горизонт) was a series of Soviet and Russian geostationary communications satellites built by NPO PM, carrying television, telephone, and maritime traffic, including Intersputnik service, from 1978 to 2000.
GPS Block IIA
GPS Block IIA was the second operational generation of GPS satellites, with 19 launched from 1990 to 1997; the last served until 2019, over three times its 7.5-year design life.
GPS Block IIF
GPS Block IIF is a generation of twelve Global Positioning System satellites built by Boeing and launched from 2010 to 2016, first to broadcast the L5 civil signal.
GPS Block III
GPS Block III is the third generation of GPS satellites built by Lockheed Martin for the US Space Force, offering greater accuracy and jam-resistant M-code signals.
GPS Block IIR
GPS Block IIR is a generation of GPS navigation satellites built by Lockheed Martin for the United States Air Force, launched between 1997 and 2004 to replenish the constellation.
GPS satellite blocks
GPS satellite blocks are the successive generations of US Global Positioning System satellites, from the experimental Block I of 1978 to GPS III and GPS III Follow-On.
GPS signals
GPS signals are the radio transmissions from Global Positioning System satellites, each combining a carrier wave, pseudorandom ranging codes, and a navigation message used to determine position, velocity, and time.
GPS tracking unit
A GPS tracking unit, also called a GPS tracker, is a device that determines its own location via satellite and transmits it over cellular or satellite links.
GPS week number rollover
The GPS week number rollover is the periodic reset of GPS's 10-bit week counter to zero every 19.7 years, which can make receivers report dates decades wrong.
GRACE and GRACE-FO
GRACE (Gravity Recovery and Climate Experiment) and GRACE-FO are twin-satellite NASA missions, launched in 2002 and 2018, that measure Earth's changing gravity field to track water and ice.
Gravity assist
A gravity assist, also known as a swing-by or gravity slingshot, is a maneuver in which a spacecraft flies close past a moving planet to gain or lose speed without spending propellant.
Gravity loss
Gravity loss is the reduction in a rocket's velocity gain caused by gravity during powered flight, typically the largest loss in an ascent to orbit.
Gravity Recovery and Interior Laboratory (GRAIL)
The Gravity Recovery and Interior Laboratory (GRAIL) was a NASA mission that used twin spacecraft, Ebb and Flow, to map the Moon's gravity field from 2011 to 2012.
Gravity turn
A gravity turn, also called a zero-lift turn, is a rocket ascent maneuver where gravity bends the trajectory from vertical flight toward the horizontal velocity needed for orbit.
Gravity well
A gravity well is the region around a mass within which objects are bound by its gravity, visualized as a depression in gravitational potential energy.
Gravity-1
Gravity-1 (Yinli-1) is a Chinese solid-propellant orbital launch vehicle developed by Orienspace, the world's largest solid rocket, capable of 6.5 tonnes to low Earth orbit.