The observations and explorations of Venus started around 1600 BC. Observations of Venus have continued into the present, as astronomers study Venus with radar and telescopes. The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University Historically Astronomy was more concerned with the classification and description of phenomena in the sky while Astrophysics attempted to explain these phenomena The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University Radar is a system that uses electromagnetic waves to identify the range altitude direction or speed of both moving and fixed objects such as Aircraft, ships A telescope is an instrument designed for the observation of remote objects and the collection of Electromagnetic radiation. As of 1961, space probes have been launched toward Venus, starting with the Soviet probe Venera 1. Year 1961 ( MCMLXI) was a Common year starting on Sunday (link will display full calendar of the Gregorian calendar. The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University A soviet (сове́т, "council" originally was a workers' local council in late Imperial Russia. February 12 1961, 003436 UTC, the first planetary probe was launched to Venus by the Soviet Union. The first successful Venus probe was NASA's Mariner 2, which flew by the planet. The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program Mariner 2 (Mariner-Venus 1962 a space probe to Venus, was the first successful Spacecraft in the NASA Mariner program. Venera 9 performed the first successful orbiting and landing on Venus. Venera 9 (Венера-9 was a USSR Unmanned space mission to Venus. The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University Currently, the European Space Agency's Venus Express is orbiting the planet. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. The European Space Agency ( ESA) established in 1975 is an intergovernmental organisation dedicated to the exploration of space, currently with 17 member Venus Express is the first Venus exploration mission of the European Space Agency.

Contents 1 Historical observations 1.1 Asia 1.2 Maya 1.3 Greeks 2 Phases 3 Transit observations 4 Terrestrial radar mapping 5 Observation by spacecraft 5.1 Flybys 5.1.1 Recent fly bys 5.2 Landings 5.2.1 Early landings 5.2.2 Venera 9 & 10 5.2.3 Pioneer Venus 5.2.4 Further Soviet successes 5.3 Magellan 5.4 Venus Express 5.5 MESSENGER 5.6 Future missions 5.7 Proposals 6 See also 7 References 8 External links

Historical observations

Asia

One of the oldest surviving astronomical documents, from the Babylonian library of Ashurbanipal around 1600 BC, is a 21-year record of the appearances of Venus (which the early Babylonians called Nindaranna). The Venus tablet of Ammisaduqa recovered from the library at Nineveh, is a 7th century BC cuneiform tablet that bears much older ( Bronze Age) Babylon was a City-state of ancient Mesopotamia, the remains of which can be found in present-day Al Hillah, Babil Province, Iraq Ashurbanipal ( Akkadian: Aššur-bāni-apli, " Ashur has made a son" or "Ashur created an heir" (b The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University

The ancient Sumerians and Babylonians called Venus Dil-bat or Dil-i-pat; in Akkadia it was the special star of the mother-god Ishtar; and in Chinese it is Jīn-xīng (金星), the planet of the metal element. Ishtar ( D IŠTAR 𒀭𒌋𒁯 is the Assyrian and Babylonian counterpart to the Sumerian Inanna and to In traditional Chinese philosophy, Metal is classified as one of the Wu xing ( or the Five Elements, also translated as five phases In India, Venus is called Shukra Graha (the planet Shukra) which is named after a powerful saint Shukra. The word 'Shukra' is also associated with semen, or generation.

Maya

Venus was considered the most important celestial body observed by the Maya, who called it Chak ek, "the Great Star", possibly more important even than the Sun. The Maya civilization is a Mesoamerican Civilization, noted for the only known fully developed written language of the Pre-Columbian Americas The Mayans monitored the movements of Venus closely and observed it in daytime. The positions of Venus and other planets were thought to influence life on Earth, so Maya and other ancient Mesoamerican cultures timed wars and other important events based on their observations. This list of pre-Columbian civilizations includes those Civilizations and Cultures of The Americas which flourished prior to the European colonization In the Dresden Codex, the Maya included an almanac showing Venus's full cycle, in five sets of 584 days each (approximately eight years), after which the patterns repeated (since Venus has a synodic period of 583. Maya codices (singular Codex) are folding Books stemming from the Pre-Columbian Maya civilization, written in Maya hieroglyphic The orbital period is the time taken for a given object to make one complete Orbit about another object 92 days).

Greeks

Early Greeks thought that the evening and morning appearances of Venus represented two different objects, calling it Hesperus when it appeared in the western evening sky and Phosphorus when it appeared in the eastern morning sky. The term ancient Greece refers to the period of Greek history lasting from the Greek Dark Ages ca They eventually came to recognize that both objects were the same planet; Pythagoras is given credit for this realization. "Pythagoras of Samos" redirects here For the Samian statuary of the same name see Pythagoras (sculptor. In the 4th century BC, Heraclides Ponticus proposed that both Venus and Mercury orbited the Sun rather than Earth. The 4th century BC started the first day of 400 BC and ended the last day of 301 BC. "Heraclides" redirects here The former Butterfly Genus of the same name is now included in Papilio.

Phases

Because its orbit takes it between the Earth and the Sun, Venus as seen from Earth exhibits visible phases in much the same manner as the Earth's Moon. In Physics, an orbit is the gravitationally curved path of one object around a point or another body for example the gravitational orbit of a planet around a star Planetary phase is the term used to describe the appearance of the illuminated section of a Planet. Galileo Galilei was the first person to observe the phases of Venus in December 1610, an observation which supported Copernicus's then contentious heliocentric description of the solar system. Galileo Galilei (15 February 1564 &ndash 8 January 1642 was a Tuscan ( Italian) Physicist, Mathematician, Astronomer, and Philosopher In Astronomy, heliocentrism is the theory that the Sun is at the center of the Solar System. He also noted changes in the size of Venus's visible diameter when it was in different phases, suggesting that it was farther from Earth when it was full and nearer when it was a crescent. This observation strongly supported the heliocentric model. Venus (and also Mercury) is not visible from Earth when it is full, since at that time it is at superior conjunction, rising and setting concomitantly with the Sun and hence lost in the Sun's glare. Conjunction is a term used in Positional astronomy and Astrology.

Venus is brightest when approximately 25% of its disk is illuminated; this typically occurs 37 days both before (in the evening sky) and after (in the morning sky), its inferior conjunction. Conjunction is a term used in Positional astronomy and Astrology. Its greatest elongations occur approximately 70 days before and after inferior conjunction, at which time it is half full; between these two intervals Venus is actually visible in broad daylight, if the observer knows specifically where to look for it. The planet's period of retrograde motion is 20 days on either side of the inferior conjunction. In fact, through a telescope Venus at greatest elongation appears less than half full due to Schröter's effect first noticed in 1793 and shown in 1996 as due to its thick atmosphere. Johann Hieronymus Schröter ( August 30 1745 &ndash August 29 1816) was a German Astronomer.

On rare occasions, Venus can actually be seen in both the morning (before sunrise) and evening (after sunset) on the same day. This scenario arises when Venus is at its maximum separation from the ecliptic and concomitantly at inferior conjunction; then one hemisphere (Northern or Southern) will be able to see it at both times. The ecliptic is the apparent path that the Sun traces out in the sky during the year This opportunity presented itself most recently for Northern Hemisphere observers within a few days on either side of March 29, 2001, and for those in the Southern Hemisphere, on and around August 19, 1999. Events 1461 - Wars of the Roses: Battle of Towton - Edward of York defeats Queen Margaret to become King Year 2001 ( MMI) was a Common year starting on Monday according to the Gregorian calendar. Events 43 BC - Octavian, later known as Augustus compels the Roman Senate to elect him Consul. Year 1999 ( MCMXCIX) was a Common year starting on Friday (link will display full 1999 Gregorian calendar) These respective events repeat themselves every eight years pursuant to the planet's synodic cycle.

Transit observations

Transits of Venus, when the planet crosses directly between the Earth and the Sun's visible disc, are rare astronomical events. A transit of Venus across the Sun takes place when the Planet Venus passes directly between the Sun and Earth, obscuring a small portion of the The first time such a transit was observed was on December 4, 1639 by Jeremiah Horrocks and William Crabtree. The term transit or astronomical transit has three meanings in astronomy A transit is the astronomical event that occurs when one "December 4th" redirects here For the song by Jay-Z, see December 4th (song. Jeremiah Horrocks (1618 &ndash January 3, 1641) sometimes given as Jeremiah Horrox (the Latinised version that he used on the Emmanuel College register William Crabtree (1610&ndash1644 was an Astronomer, Mathematician, and merchant from Broughton, then a Township near Manchester, A transit in 1761 observed by Mikhail Lomonosov provided the first evidence that Venus had an atmosphere, and the 19th-century observations of parallax during its transits allowed the distance between the Earth and Sun to be accurately calculated for the first time. Year 1761 ( MDCCLXI) was a Common year starting on Thursday (link will display the full calendar of the Gregorian calendar (or a Mikhail Vasilyevich Lomonosov (Михаи́л Васи́льевич Ломоно́сов () was a Russian Polymath, scientist Parallax is an apparent displacement or difference of orientation of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between Transits can only occur either in early June or early December, these being the points at which Venus crosses the ecliptic (the orbital plane of the Earth), and occur in pairs at eight-year intervals, with each such pair more than a century apart. The previous pair of transits of Venus occurred in 1874 and 1882, and the current pair is in 2004 and 2012. Year 1874 ( MDCCCLXXIV) was a Common year starting on Thursday (link will display the full calendar of the Gregorian calendar (or a Common Year 1882 ( MDCCCLXXXII) was a Common year starting on Sunday (link will display the full calendar of the Gregorian calendar (or a Common "MMIV" redirects here For the Modest Mouse album see " Baron von Bullshit Rides Again " 2012 ( MMXII) will be a Leap year starting on Sunday of the Gregorian calendar.

In the 19th century, many observers stated that Venus had a period of rotation of roughly 24 hours. The 19th century of the Common Era began on January 1, 1801 and ended on December 31, 1900, according to the Gregorian calendar Italian astronomer Giovanni Schiaparelli was the first to predict a significantly slower rotation, proposing that Venus was tidally locked with the Sun (as he had also proposed for Mercury). Honors and Awards Awards Gold Medal of the Royal Astronomical Society (1872 Bruce Medal (1902 Named A separate article treats the phenomenon of Tidal resonance in Oceanography. While not actually true for either body, this was still a reasonably accurate estimate. The near-resonance between its rotation and its closest approach to Earth helped to create this impression, as Venus always seemed to be facing the same direction when it was in the best location for observations to be made. The rotation rate of Venus was first measured during the 1961 conjunction, observed by radar from a 26 m antenna at Goldstone, California, the Jodrell Bank Radio Observatory in the UK, and the Soviet deep space facility in Eupatoria, Crimea. Year 1961 ( MCMLXI) was a Common year starting on Sunday (link will display full calendar of the Gregorian calendar. The Goldstone Deep Space Communications Complex ( GDSCC) &mdashcommonly called the Goldstone Observatory &mdash is located in California 's Mojave Desert The Jodrell Bank Observatory (originally the Jodrell Bank Experimental Station, then the Nuffield Radio Astronomy Laboratories from 1966 to 1999 is an Observatory The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located The Union of Soviet Socialist Republics (USSR was a constitutionally Socialist state that existed in Eurasia from 1922 to 1991 For the lake Kerkinitis see Kerkini Eupatoria or Yevpatoria (Євпаторія Евпатория Kezlev Eupatoria Kerkinitis is a city in Crimea Crimea (kraɪˈmiːə or the Autonomous Republic of Crimea (Крим Автономна Республіка Крим Avtonomna Respublika Krym; Крым Accuracy was refined at each subsequent conjunction, primarily from measurements made from Goldstone and Eupatoria. The fact that rotation was retrograde was not confirmed until 1964. Year 1964 ( MCMLXIV) was a Leap year starting on Wednesday (link will display full calendar of the 1964 Gregorian calendar.

Before radio observations in the 1960s, many believed that Venus contained a lush, Earth-like environment. The 1960s decade refers to the years from the beginning of 1960 to the end of 1969 This was due to the planet's size and orbital radius, which suggested a fairly Earthlike situation as well as to the thick layer of clouds which prevented the surface from being seen. Among the speculations on Venus were that it had a junglelike environment or that it had oceans of either petroleum or carbonated water. Petroleum ( L petroleum, from Greek πετρέλαιον, lit However, microwave observations in 1956, by C. Year 1956 ( MCMLVI) was a Leap year starting on Sunday (link will display full calendar of the Gregorian calendar. Mayer et al, indicated a high-temperature source (600 K). Strangely, millimetre-band observations made by A. D. Kuzmin indicated much lower temperatures. Two competing theories explained the unusual radio spectrum, one suggesting the high temperatures originated in the ionosphere, and another suggesting a hot planetary surface.

Terrestrial radar mapping

After the Moon, Venus was the second object in the solar system to be explored by radar from the Earth. The Solar System consists of the Sun and those celestial objects bound to it by Gravity. The first studies were carried out in 1961 at NASA's Goldstone Observatory, part of the Deep Space Network. Year 1961 ( MCMLXI) was a Common year starting on Sunday (link will display full calendar of the Gregorian calendar. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program The Goldstone Deep Space Communications Complex ( GDSCC) &mdashcommonly called the Goldstone Observatory &mdash is located in California 's Mojave Desert The Deep Space Network, or DSN, is an international network of communication facilities that supports Interplanetary Spacecraft missions and At successive inferior conjunctions, Venus was observed both by Goldstone and the National Astronomy and Ionosphere Center in Arecibo. Conjunction is a term used in Positional astronomy and Astrology. The Arecibo Observatory is a very sensitive Radio telescope located approximately south-southwest from the town of Arecibo in Puerto Rico. Arecibo (ah-re-SEE-boh is a municipality in the northern midwest coast of Puerto Rico and located by the Atlantic Ocean north of Utuado and Ciales The studies carried out were similar to the earlier measurement of transits of the meridian, which had revealed in 1963 that the rotation of Venus was retrograde (it rotates in the opposite direction to that in which it orbits the Sun). This article is about the astronomical concept For other uses of the word see Meridian. Direct motion is the motion of a Planetary body in a direction similar to that of other bodies within its system and is sometimes called prograde motion. The radar observations also allowed astronomers to determine that the rotation period of Venus was 243. The rotation period of an astronomical object is the time it takes to complete one revolution around its Axis of rotation relative to the background stars 1 days, and that its axis of rotation was almost perpendicular to its orbital plane. A rotation is a movement of an object in a circular motion A two- Dimensional object rotates around a center (or point) of rotation The orbital plane of an object orbiting another is the geometrical plane in which the orbit is embedded. It was also established that the radius of the planet was 6,052 kilometres (3761 mi), some 70 kilometres (43 mi) less than the best previous figure obtained with terrestrial telescopes. Remote Authentication Dial In User Service ( RADIUS) is a networking protocol that provides centralized access authorization and accounting management for people or computers

Interest in the geological characteristics of Venus was stimulated by the refinement of imaging techniques between 1970 and 1985. Planetary geology, alternatively known as astrogeology or exogeology, is a Planetary science discipline concerned with the Geology of the Year 1970 ( MCMLXX) was a Common year starting on Thursday (link shows full calendar of the Gregorian calendar. Year 1985 ( MCMLXXXV) was a Common year starting on Tuesday (link displays 1985 Gregorian calendar) Early radar observations suggested merely that the surface of Venus was more compacted than the dusty surface of the Moon. The first radar images taken from the Earth showed very bright (radar-reflective) highlands christened Alpha Regio, Beta Regio, and Maxwell Montes; improvements in radar techniques later achieved an image resolution of 1–2 kilometres. Alpha Regio is a region of the planet Venus extending for about 1500 kilometers centered at 22°S 5°E Beta Regio is a region of the planet Venus known as a volcanic rise. Maxwell Montes is a Mountain Massif on the planet Venus, part of which contains the highest point on the planet's surface

Observation by spacecraft

There have been numerous unmanned missions to Venus. Ten Russian probes have included a soft landing on the surface, with up to 110 minutes of communication from the surface, all without return. Launch windows occur every 19 months, and from 1962 to 1985, every window was utilized to launch reconnaissance probes. Launch window is a term used in Aerospace to describe a time period in which a particular Rocket must be launched Year 1962 ( MCMLXII) was a Common year starting on Monday (the link is to a full 1962 calendar of the Gregorian calendar. Year 1985 ( MCMLXXXV) was a Common year starting on Tuesday (link displays 1985 Gregorian calendar)

Flybys

On February 12, 1961, the Soviet spacecraft Venera 1 was the first probe launched to another planet. Events 1429 - English Forces under Sir John Fastolf defend a supply convoy carrying rations to the army besieging Orleans from attack by the Year 1961 ( MCMLXI) was a Common year starting on Sunday (link will display full calendar of the Gregorian calendar. The Soviet space program consisted of initiatives within the Soviet Union by competing design groups February 12 1961, 003436 UTC, the first planetary probe was launched to Venus by the Soviet Union. A robotic spacecraft is a Spacecraft with no humans on board that is usually under Telerobotic control An overheated orientation sensor caused it to malfunction, but Venera-1 was first to combine all the necessary features of an interplanetary spacecraft: solar panels, parabolic telemetry antenna, 3-axis stabilization, course-correction engine, and the first launch from parking orbit.

The first successful Venus probe was the American Mariner 2 spacecraft, which flew past Venus in 1962. The United States of America —commonly referred to as the Mariner 2 (Mariner-Venus 1962 a space probe to Venus, was the first successful Spacecraft in the NASA Mariner program. Year 1962 ( MCMLXII) was a Common year starting on Monday (the link is to a full 1962 calendar of the Gregorian calendar. A modified Ranger Moon probe, it established that Venus has practically no intrinsic magnetic field and measured the planet's thermal microwave emissions. The Ranger program was a series of Unmanned space missions by the United States in the 1960s whose objective was to obtain the first close-up images of the surface In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges

• The Soviet Union launched the Zond 1 probe to Venus on April 2, 1964, but it malfunctioned sometime after its May 16 telemetry session. The Union of Soviet Socialist Republics (USSR was a constitutionally Socialist state that existed in Eurasia from 1922 to 1991 Zond 1 was a member of the Soviet Zond program. It was the second Soviet research spacecraft to successfully reach Venus although communications had failed by that time Events 68 - Galba, Governor of Hispania, names himself legatus senatus populique Romani, breaking the line of Year 1964 ( MCMLXIV) was a Leap year starting on Wednesday (link will display full calendar of the 1964 Gregorian calendar.
• In 1965, Venera 3 became the first space probe to actually impact into another planet. Venera 3 ( Russian:Венера-3 was a Venera program Space probe that was built and launched by the Soviet Union to explore the surface of
• In 1967, Venera 4 became the first probe to send data from the interior of Venus's atmosphere. Venera 4 ( Russian:Венера-4 was a probe in the Soviet Venera program for the exploration of Venus. At about the same time, Mariner 5 measured the strength of Venus's magnetic field. Mariner 5 (Mariner Venus '67 was a spacecraft of the Mariner program that carried a complement of experiments to probe Venus ' atmosphere by radio occultation In Physics, a magnetic field is a Vector field that permeates space and which can exert a magnetic force on moving Electric charges
• In 1974, Mariner 10 swung by Venus on its way to Mercury and took ultraviolet photographs of the clouds, revealing the extraordinarily high wind speeds in the Venusian atmosphere. Mariner 10 was a robotic Space probe launched on November 3, 1973 to fly by the planets Mercury and Venus.

Recent fly bys

Several space probes en route to other destinations have used flybys of Venus to increase their speed via the gravitational slingshot method. In Orbital mechanics and Aerospace engineering, a gravitational slingshot, gravity assist or swing-by is the use of the relative movement and These include the Galileo mission to Jupiter and the Cassini-Huygens Mission to Saturn (two flybys). Galileo was an Unmanned spacecraft sent by NASA to study the Planet Jupiter and its moons Named after the Astronomer Cassini–Huygens is a joint NASA / ESA / ASI Robotic spacecraft mission currently studying the planet Saturn and its Rather curiously, during Cassini's examination of the radiofrequency emissions of Venus with its radio and plasma wave science instrument during both the 1998 and 1999 flybys, it reported no high-frequency radio waves (0. Radio frequency ( RF) is a Frequency or rate of Oscillation within the range of about 3 Hz to 300 GHz 125 to 16 MHz), which are commonly associated with lightning. This was in direct opposition to the findings of the Soviet Venera missions 20 years earlier. It was postulated that perhaps if Venus did have lightning, it might be some type of low-frequency electrical activity, due to the fact that radio signals cannot penetrate the ionosphere at frequencies below about 1 megahertz. An examination by physicist Donald Gurnett of the University of Iowa of radio emissions of Venus by the Galileo spacecraft during its gravity assist flyby in 1990 did reveal what were interpreted at the time to be indicative of lightning. However the Galileo probe was over 60 times as distant to Venus as was Cassini during its flyby, making its observations substantially less significant. The mystery as to whether or not Venus does in fact have lightning in its atmosphere was not solved until 2007, when the scientific journal Nature published a series of papers giving the initial findings of the Venus Express. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Nature is a prominent Scientific journal, first published on 4 November 1869 Venus Express is the first Venus exploration mission of the European Space Agency. It confirmed the presence of lightning on Venus and that it is more common on Venus than it is on Earth^{[1] [2]}.

Landings

Early landings

On March 1, 1966 the Venera 3 Soviet space probe crash-landed on Venus, becoming the first spacecraft to reach the planet's surface. Events 86 BC - Lucius Cornelius Sulla, at the head of a Roman Republic army enters in Athens, removing the Tyrant Year 1966 ( MCMLXVI) was a Common year starting on Saturday (link will display full calendar of the 1966 Gregorian calendar. Venera 3 ( Russian:Венера-3 was a Venera program Space probe that was built and launched by the Soviet Union to explore the surface of A space probe is a scientific Space exploration mission in which a Robotic spacecraft leaves the Gravity well of Earth and approaches the Its sister craft Venera 2 had failed from overheating shortly before completing its flyby mission. Venera 2 (Венера-2 was a probe in the Soviet Venera program for the exploration of Venus.

The descent capsule of Venera 4 entered the atmosphere of Venus on October 18, 1967. Venera 4 ( Russian:Венера-4 was a probe in the Soviet Venera program for the exploration of Venus. Events 1009 - The Church of the Holy Sepulchre, a Christian church in Jerusalem, is completely destroyed by the Fatimid Year 1967 ( MCMLXVII) was a Common year starting on Sunday (link will display full calendar of the 1967 Gregorian calendar. The first probe to return direct measurements from another planet, the capsule measured temperature, pressure, density and performed 11 automatic chemical experiments to analyze the atmosphere. It showed 95% carbon dioxide, and in combination with radio occultation data from the Mariner 5 probe, it showed that surface pressures were far greater than expected (75 to 100 atmospheres). Mariner 5 (Mariner Venus '67 was a spacecraft of the Mariner program that carried a complement of experiments to probe Venus ' atmosphere by radio occultation

These results were verified and refined by the Venera 5 and Venera 6 missions on May 16 and 17 of 1969. Venera 5 (Венера-5 was a probe in the Soviet space program ''Venera'' for the exploration of Venus. Venera 6 ( Russian:Венера-6 was a Soviet Spacecraft, launched from a Tyazheliy Sputnik (69-002C on January 10 1969 Events 1204 - Baldwin IX Count of Flanders is crowned as the first Emperor of the Latin Empire. Events 1521 - Edward Stafford 3rd Duke of Buckingham, is executed for Treason. Year 1969 ( MCMLXIX) was a Common year starting on Wednesday (link will display full calendar of the Gregorian calendar. But thus far, none of these missions had reached the surface while still transmitting. Venera 4's battery ran out while still slowly floating through the massive atmosphere, and Venera 5 and 6 were crushed by high pressure 18 km (60,000 ft) above the surface.

The first successful landing on Venus was by Venera 7 on December 15, 1970. The Venera 7 (Венера-7 was a Soviet Spacecraft part of the Venera series of probes to Venus. Events 533 - Byzantine general Belisarius defeats the Vandals, commanded by King Gelimer, at the Battle of Year 1970 ( MCMLXX) was a Common year starting on Thursday (link shows full calendar of the Gregorian calendar. It relayed surface temperatures of 455 °C to 475 °C (855 °F to 885 °F). Venera 8 landed on July 22, 1972. Venera 8 (Венера-8 was a probe in the Soviet Venera program for the exploration of Venus. Events 1099 - First Crusade: Godfrey of Bouillon is elected the first Defender of the Holy Sepulchre of The Kingdom of Year 1972 ( MCMLXXII) was a Leap year starting on Saturday (link will display full calendar of the Gregorian calendar. In addition to pressure and temperature profiles, a photometer showed that the clouds of Venus formed a layer, ending over 22 miles above the surface. A gamma ray spectrometer analyzed the chemical composition of the crust. A Gamma-Ray Spectrometer, or (GRS is an instrument for measuring the distribution (or Spectrum —see figure) of the intensity of gamma radiation versus the energy

Venera 9 & 10

The Soviet probe Venera 9 entered orbit on October 22, 1975, becoming the first artificial satellite of Venus. Venera 9 (Венера-9 was a USSR Unmanned space mission to Venus. Events 202 BC - Hannibal Barca, leader of the Carthaginians, is defeated by the Roman legions under Scipio Africanus Year 1975 ( MCMLXXV) was a Common year starting on Wednesday (link will display full calendar of the Gregorian calendar. A battery of cameras and spectrometers returned information about the planet's clouds, ionosphere and magnetosphere, as well as performing bistatic radar measurements of the surface.

The 660 kg (1,455 lb) descent vehicle[2] separated from Venera 9 and landed, taking the first pictures of the surface and analyzing the crust with a gamma ray spectrometer and a densitometer. During descent, pressure, temperature and photometric measurements were made, as well as backscattering and multi-angle scattering (nephelometer) measurements of cloud density. A nephelometer is an instrument for measuring suspended particulates in a Liquid or Gas Colloid. It was discovered that the clouds of Venus are formed in three distinct layers. On October 25, Venera 10 arrived and carried out a similar program of study. Events 1147 - The Portuguese, under Afonso I, and Crusaders from England and Flanders conquer Lisbon after a Venera 10 (Венера-10 was a USSR Unmanned space mission to Venus.

Pioneer Venus

In 1978, NASA sent two Pioneer spacecraft to Venus. Year 1978 ( MCMLXXVIII) was a Common year starting on Sunday (link displays the 1978 Gregorian calendar) The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program The Pioneer mission to Venus consisted of two components launched separately The Pioneer mission consisted of two components, launched separately: an Orbiter and a Multiprobe. The Pioneer Venus Multiprobe carried one large and three small atmospheric probes. The Pioneer mission to Venus consisted of two components launched separately The large probe was released on November 16, 1978 and the three small probes on November 20. Events 534 - A second and final revision of the Codex Justinianus is published Year 1978 ( MCMLXXVIII) was a Common year starting on Sunday (link displays the 1978 Gregorian calendar) Events 284 - Diocletian was chosen as Roman Emperor. 762 - Bögü Khan of the Uyghurs, All four probes entered the Venus atmosphere on December 9, followed by the delivery vehicle. Events 536 - Byzantine General Belisarius enters Rome while the Ostrogothic garrison peacefully leaves the city Although not expected to survive the descent through the atmosphere, one probe continued to operate for 45 minutes after reaching the surface. The Pioneer Venus Orbiter was inserted into an elliptical orbit around Venus on December 4, 1978. The Pioneer mission to Venus consisted of two components launched separately "December 4th" redirects here For the song by Jay-Z, see December 4th (song. Year 1978 ( MCMLXXVIII) was a Common year starting on Sunday (link displays the 1978 Gregorian calendar) It carried 17 experiments and operated until the fuel used to maintain its orbit was exhausted and atmospheric entry destroyed the spacecraft in August 1992. Year 1992 ( MCMXCII) was a Leap year starting on Wednesday (link will display full 1992 Gregorian calendar)

Further Soviet successes

Also in 1978, Venera 11 and Venera 12 flew past Venus, dropping descent vehicles on December 21 and December 25 respectively. Year 1978 ( MCMLXXVIII) was a Common year starting on Sunday (link displays the 1978 Gregorian calendar) The Venera 11 (Венера-11 was an USSR Unmanned space mission part of the Venera program to explore the planet Venus. The Venera 12 (Венера-12 was an USSR Unmanned space mission to explore the planet Venus. Events 69 - The end of the Year of the four emperors: Following Galba, Otho and Vitellius, Vespasian Events 274 - Roman Emperor Aurelian The landers carried colour cameras and a soil drill and analyzer, which unfortunately malfunctioned. Each lander made measurements with a nephelometer, mass spectrometer, gas chromatograph, and a cloud-droplet chemical analyzer using X-ray fluorescence that unexpectedly discovered a large proportion of chlorine in the clouds, in addition to sulfur. A nephelometer is an instrument for measuring suspended particulates in a Liquid or Gas Colloid. Mass spectrometry is an analytical technique that identifies the chemical composition of a compound or sample based on the Mass-to-charge ratio of charged particles Gas-liquid chromatography (GLC, or simply gas chromatography (GC, is a type of Chromatography in which the mobile phase is a carrier gas usually an Inert X-ray fluorescence (XRF is the emission of characteristic "secondary" (or fluorescent X-rays from a material that has been excited by bombarding with high-energy Strong lightning activity was also detected. Lightning is an atmospheric discharge of Electricity, which typically occurs during Thunderstorms and sometimes during volcanic eruptions or

In 1981, the Soviet Venera 13 sent the first colour image of Venus's surface and analysed the X-ray fluorescence of an excavated soil sample. Year 1981 ( MCMLXXXI) was a Common year starting on Thursday (link displays the 1981 Venera 13 (Венера-13 was a probe in the Soviet Venera program for the exploration of Venus. X-ray fluorescence (XRF is the emission of characteristic "secondary" (or fluorescent X-rays from a material that has been excited by bombarding with high-energy The probe operated for a record 127 minutes on the planet's hostile surface. Also in 1981, the Venera 14 lander detected possible seismic activity in the planet's crust. Venera 14 (Венера-14 was a probe in the Soviet Venera program for the exploration of Venus. Seismology (from Greek grc σεισμός seismos, "earthquake" and grc -λογία -logia) is the scientific study of Earthquakes

On October 10 and October 11, 1983, Venera 15 and Venera 16 entered polar orbits around Venus. Events 680 - Battle of Karbala: Shia Imam Husayn bin Ali, the grandson of the Prophet Muhammad, is decapitated Events 1138 - A massive earthquake struck Aleppo, Syria. 1531 - Huldrych Zwingli is killed Year 1983 ( MCMLXXXIII) was a Common year starting on Saturday (link displays the 1983 Gregorian calendar) Venera 15 (Венера-15 was a Spacecraft sent to Venus by the Soviet Union. Venera 16 (Венера-16 was a Spacecraft sent to Venus by the Soviet Union. The images had a 1–2 kilometre (0. 6–1. 2 mile) resolution, comparable to those obtained by the best Earth radars. Venera 15 analyzed and mapped the upper atmosphere with an infrared Fourier spectrometer. The Planetary Fourier Spectrometer ( PFS) is an Infrared Spectrometer built by the Istituto Nazionale di Astrofisica (Italian National Institute From November 11 to July 10, both satellites mapped the northern third of the planet with synthetic aperture radar. Events 308 - The Congress of Carnuntum: Attempting to keep peace within the Roman Empire, the leaders of the Tetrarchy declare Events 48 BC - Battle of Dyrrhachium, Julius Caesar barely avoids a catastrophic defeat to Pompey in Macedonia. Synthetic-aperture radar (SAR is a form of Radar in which the highly-directional (and thus very large rotating antenna used by conventional radar is replaced with many low-directivity These results provided the first detailed understanding of the surface geology of Venus, including the discovery of unusual massive shield volcanoes such as coronae and arachnoids. In Astrogeology, an arachnoid is a large structure of unknown origin and they have been found only on the surface of the Planet Venus. Venus had no evidence of plate tectonics, unless the northern third of the planet happened to be a single plate. The altimetry data obtained by the Venera missions had a resolution four times better than Pioneer's. In 1985, during the euphoria of Halley's comet, the Soviet Union launched two Vega probes to Venus. Year 1985 ( MCMLXXXV) was a Common year starting on Tuesday (link displays 1985 Gregorian calendar) Halley's Comet, officially designated 1P/Halley and also referred to as Comet Halley after Edmond Halley, is a Comet that can be seen every Vega program were a series of Venus missions which also took advantage of the appearance of Comet Halley in 1986 Vega 1 and 2 each sent an instrumented helium balloon to a height of 50 kilometres (31 mi) above the surface, allowing scientists to study the dynamics of the most active part of Venus's atmosphere. Atmospheric physics is the application of Physics to the study of the atmosphere.

The Soviet Vega 1 and Vega 2 probes encountered Venus on June 11 and June 15 of 1985. Vega 1 (along with its twin Vega 2) is a Soviet Space probe part of the Vega program. Vega 2 (along with Vega 1) is a Soviet Space probe part of the Vega program. Events 1184 BC - Trojan War: Troy is sacked and burned according to the calculations of Eratosthenes. Events 763 BC - Assyrians record a Solar eclipse that will be used to fix the Chronology of Mesopotamian history Year 1985 ( MCMLXXXV) was a Common year starting on Tuesday (link displays 1985 Gregorian calendar) Landing vehicles carried experiments focusing on cloud aerosol composition and structure. Each carried an ultraviolet absorption spectrometer, aerosol particle-size analyzers, and devices for collecting aerosol material and analyzing it with a mass spectrometer, a gas chromatograph, and an X-ray fluorescence spectrometer. The upper two layers of the clouds were found to be sulfuric acid droplets, but the lower layer is probably composed of phosphoric acid solution. The crust of Venus was analyzed with the soil drill experiment and a gamma ray spectrometer. As the landers carried no cameras on board, no images were returned from the surface.

The Vega missions also deployed balloon-borne aerostat probes that floated at about 53 km altitude respectively for 46 and 60 hours, traveling about 1/3 of the way around the planet. Gallery Types of aerostats See also Aerodyne Aerostatics Airship Balloon These measured wind speed, temperature, pressure and cloud density. More turbulence and convection activity than expected was discovered, including occasional plunges of 1 to 3 km in downdrafts. The Vega spacecraft continued to rendezvous with Halley's Comet nine months later, bringing an additional 14 instruments and cameras for that mission. Halley's Comet, officially designated 1P/Halley and also referred to as Comet Halley after Edmond Halley, is a Comet that can be seen every

Magellan

On August 10, 1990, the US Magellan probe arrived at its orbit around the planet and started a mission of detailed radar mapping. Events 612 BC - Killing of Sinsharishkun, King of Assyrian Empire Year 1990 ( MCMXC) was a Common year starting on Monday (link displays the 1990 Gregorian calendar) The Magellan spacecraft was a space probe sent to the planet Venus, the first post- Voyager unmanned spacecraft to be launched by NASA Radar is a system that uses electromagnetic waves to identify the range altitude direction or speed of both moving and fixed objects such as Aircraft, ships 98% of the surface was mapped with a resolution of approximately 100 m. After a four-year mission, Magellan, as planned, plunged into the atmosphere on October 11, 1994, and partly vaporized; some sections are thought to have hit the planet's surface. Events 1138 - A massive earthquake struck Aleppo, Syria. 1531 - Huldrych Zwingli is killed Year 1994 ( MCMXCIV) was a Common year starting on Saturday (link will display full 1994 Gregorian calendar)

Venus Express

Venus Express is a mission prepared by the European Space Agency to study the atmosphere and surface characteristics of Venus from orbit. Venus Express is the first Venus exploration mission of the European Space Agency. The European Space Agency ( ESA) established in 1975 is an intergovernmental organisation dedicated to the exploration of space, currently with 17 member The probe successfully assumed orbit around Venus on April 11, 2006. Events 491 - Flavius Anastasius becomes Byzantine Emperor, with the name of Anastasius I. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. The mapping mission is expected to last for two Venusian years (about 500 Earth days). One of the first results emerging from Venus Express is the discovery that a huge double atmospheric vortex exists at the south pole of the planet. The polar vortex is a persistent large-scale Cyclone located near the Earth's Poles, in the middle and upper Troposphere and the Stratosphere

MESSENGER

MESSENGER, on its way to Mercury passed by Venus twice. The MErcury Surface Space ENvironment GEochemistry and Ranging ( MESSENGER) probe is a NASA Spacecraft, launched August 3, 2004 The first time, it flew by on October 24, 2006, passing 1,860 miles from Venus. Events 69 - Second Battle of Bedriacum, forces under Antonius Primus the commander of the Danube armies loyal to Vespasian, defeat Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. The VENUS ( V ictoria E xperimental N etwork U nder the S ea project is a cabled sea floor observatory operated by the University As Earth was on the other side of the Sun, no data was recorded. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 The Sun (Sol is the Star at the center of the Solar System. ^[3] The second flyby was on July 6, 2007, where the spacecraft passed only 200 miles from the cloudtops. Events 1044 - The Battle of Ménfő takes place 1189 - Richard the Lionheart is crowned King of England Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. ^[4]

Future missions

Future fly-bys en route to other destinations include BepiColombo to Mercury. BepiColombo is a joint Cornerstone mission of the European Space Agency (ESA and the Japan Aerospace Exploration Agency (JAXA to the planet Mercury Two other spacecraft are also proposed to orbit and possibly deploy another lander on Venus; PLANET-C (JAXA) and Venera-D (Roskosmos). PLANET-C, also known as Venus Climate Orbiter (VCO is a planned Japanese Unmanned spacecraft to explore Venus. The, or JAXA, is Japan's national Aerospace agency JAXA was formed on October 1 2003 as an Independent Administrative Institution through the The Venera-D (Венера-Д probe is a proposed Russian space probe to Venus, to be launched around 2016 The Russian Federal Space Agency ( Russian: Федеральное космическое агентство России Federal'noe kosmicheskoe agentstvo Rossii

Proposals

To overcome the hellish surface conditions, a team led by Geoffrey Landis of NASA's Glenn Research Center in Ohio has proposed a Venus Rover mission that includes a tough surface rover in communication with a solar-powered aircraft. Geoffrey A Landis works as a scientist and writer of Science fiction. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program NASA John H Glenn Research Center at Lewis Field (see History for previous names is a NASA center located within the cities of Brook Park Ohio ( is a Midwestern state of the United States. As part of the Great Lakes region, Ohio has long been a cultural and geographical crossroads The aircraft would carry the mission's sensitive electronics in the relatively mild temperatures of Venus' upper atmosphere. ^[5] Another more recent rover design proposal by Landis uses a Stirling cooler powered by a nuclear power source to keep an electronics package at a relatively comfortable 200°C. A Stirling engine is a closed-cycle regenerative Heat engine with a Gaseous working fluid ^[6]

Landis also makes a case for Venus as a target for human colonization. The colonization of Venus has been a subject of much speculation and many works of science fiction since before the dawn of Spaceflight, and is still much discussed At 50 km above the surface, the temperature range is 0-50°C, the air pressure drops to 1 atmosphere, the gravity is 0. 9 that of Earth, and the resources for life are plentiful. ^[7]

See also

• Venus
• Aspects of Venus
• Manned Venus Flyby

References

External links

• Double vortex at Venus South Pole unveiled!
• Planetary Missions at National Space Science Data Center (NASA)

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