Venus is the second planet from the Sun. It is a terrestrial planet and is the closest in mass and size to its orbital neighbour Earth. Venus is notable for having the densest atmosphere of the terrestrial planets,composed mostly of carbon dioxide with a thick,global sulfuric acid cloud cover. At the surface it has a mean temperature of 737 K and a pressure of 92 times that of Earth's at sea level. These conditions are extreme enough to compress carbon dioxide into a supercritical state close to Venus's surface.
The Venera program was the name given to a series of space probes developed by the Soviet Union between 1961 and 1984 to gather information about the planet Venus.
The Discovery Program is a series of Solar System exploration missions funded by the U.S. National Aeronautics and Space Administration (NASA) through its Planetary Missions Program Office. The cost of each mission is capped at a lower level than missions from NASA's New Frontiers or Flagship Programs. As a result,Discovery missions tend to be more focused on a specific scientific goal rather than serving a general purpose.
Venera 9,manufacturer's designation:4V-1 No. 660,was a Soviet uncrewed space mission to Venus. It consisted of an orbiter and a lander. It was launched on June 8,1975,at 02:38:00 UTC and had a mass of 4,936 kilograms (10,882 lb). The orbiter was the first spacecraft to orbit Venus,while the lander was the first to return images from the surface of another planet.
Venera 6,or 2V (V-69) No.331,was a Soviet spacecraft,launched towards Venus to obtain atmospheric data. It had an on-orbit dry mass of 1,130 kg (2,490 lb).
Venus Express (VEX) was the first Venus exploration mission of the European Space Agency (ESA). Launched in November 2005,it arrived at Venus in April 2006 and began continuously sending back science data from its polar orbit around Venus. Equipped with seven scientific instruments,the main objective of the mission was the long term observation of the Venusian atmosphere. The observation over such long periods of time had never been done in previous missions to Venus,and was key to a better understanding of the atmospheric dynamics. ESA concluded the mission in December 2014.
Venera 4,also designated 4V-1 No.310,was a probe in the Soviet Venera program for the exploration of Venus. The probe comprised a lander,designed to enter the Venusian atmosphere and parachute to the surface,and a carrier/flyby spacecraft,which carried the lander to Venus and served as a communications relay for it.
Venera 5 was a space probe in the Soviet space program Venera for the exploration of Venus.
Venera 13 was part of the Soviet Venera program meant to explore Venus.
Venera 14 was a probe in the Soviet Venera program for the exploration of Venus.
Observations of the planet Venus include those in antiquity,telescopic observations,and from visiting spacecraft. Spacecraft have performed various flybys,orbits,and landings on Venus,including balloon probes that floated in the atmosphere of Venus. Study of the planet is aided by its relatively close proximity to the Earth,compared to other planets,but the surface of Venus is obscured by an atmosphere opaque to visible light.
The atmosphere of Venus is the very dense layer of gasses surrounding the planet Venus. Venus's atmosphere is composed of 96.5% carbon dioxide and 3.5% nitrogen,with other chemical compounds present only in trace amounts. It is much denser and hotter than that of Earth;the temperature at the surface is 740 K,and the pressure is 93 bar (1,350 psi),roughly the pressure found 900 m (3,000 ft) under water on Earth. The atmosphere of Venus supports decks of opaque clouds of sulfuric acid that cover the entire planet,making optical Earth-based and orbital observation of the surface impossible. Information about surface topography has been obtained exclusively by radar imaging.
Venera-D is a proposed Russian space mission to Venus that would include an orbiter and a lander to be launched in 2029. The orbiter's prime objective is to perform observations with the use of a radar. The lander,based on the Venera design,would be capable of operating for a long duration on the planet's surface. The "D" in Venera-D stands for "dolgozhivuschaya," which means "long lasting" in Russian.
The possibility of life on Venus is a subject of interest in astrobiology due to Venus' proximity and similarities to Earth. To date,no definitive evidence has been found of past or present life there. In the early 1960s,studies conducted via spacecraft demonstrated that the current Venusian environment is extreme compared to Earth's. Studies continue to question whether life could have existed on the planet's surface before a runaway greenhouse effect took hold,and whether a relict biosphere could persist high in the modern Venusian atmosphere.
James B. Garvin served as NASA's Chief Scientist from October 2004 to September 2005 and is known for his foundational work in NASA's Mars explorational programs.
Lori Glaze is an American scientist and the director of NASA's Science Mission Directorate's Planetary Science Division. She was a member of the Inner Planets Panel during the most recent Planetary Science Decadal Survey,and has had a role on the Executive Committee of NASA's Venus Exploration Analysis Group (VEXAG) for several years,serving as the group's Chair from 2013–2017.
SPRITE was a proposed Saturn atmospheric probe mission concept of the NASA. SPRITE is a design for an atmospheric entry probe that would travel to Saturn from Earth on its own cruise stage,then enter the atmosphere of Saturn,and descend taking measurements in situ.
Venus Origins Explorer (VOX) is a concept orbiter mission to Venus.
EnVision is an orbital mission to Venus being developed by the European Space Agency (ESA) that is planned to perform high-resolution radar mapping and atmospheric studies. EnVision is designed to help scientists understand the relationships between its geological activity and the atmosphere,and it would investigate why Venus and Earth took such different evolutionary paths. The probe was selected as the fifth medium mission (M5) of ESA's Cosmic Vision programme in June 2021,with launch planned for 2031. The mission will be conducted in collaboration with NASA,with the potential sharing of responsibilities currently under assessment.
