Van Allen radiation belt
A Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind, that are captured by and held around a planet by that planet's magnetic field. Earth has two such belts and sometimes others may be temporarily created; the discovery of the belts is credited to James Van Allen, as a result, Earth's belts are known as the Van Allen belts. Earth's two main belts extend from an altitude of about 640 to 58,000 km above the surface in which region radiation levels vary. Most of the particles that form the belts are thought to come from solar wind and other particles by cosmic rays. By trapping the solar wind, the magnetic field deflects those energetic particles and protects the atmosphere from destruction; the belts are located in the inner region of Earth's magnetosphere. The belts trap energetic protons. Other nuclei, such as alpha particles, are less prevalent; the belts endanger satellites, which must have their sensitive components protected with adequate shielding if they spend significant time near that zone.
In 2013, NASA reported that the Van Allen Probes had discovered a transient, third radiation belt, observed for four weeks until it was destroyed by a powerful, interplanetary shock wave from the Sun. Kristian Birkeland, Carl Størmer, Nicholas Christofilos had investigated the possibility of trapped charged particles before the Space Age. Explorer 1 and Explorer 3 confirmed the existence of the belt in early 1958 under James Van Allen at the University of Iowa; the trapped radiation was first mapped by Explorer 4, Pioneer 3 and Luna 1. The term Van Allen belts refers to the radiation belts surrounding Earth; the Sun does not support long-term radiation belts, as it lacks a stable, dipole field. The Earth's atmosphere limits the belts' particles to regions above 200–1,000 km, while the belts do not extend past 8 Earth radii RE; the belts are confined to a volume. The NASA Van Allen Probes mission aims at understanding how populations of relativistic electrons and ions in space form or change in response to changes in solar activity and the solar wind.
NASA Institute for Advanced Concepts–funded studies have proposed magnetic scoops to collect antimatter that occurs in the Van Allen belts of Earth, although only about 10 micrograms of antiprotons are estimated to exist in the entire belt. The Van Allen Probes mission launched on August 30, 2012; the primary mission is scheduled to last two years with expendables expected to last four. NASA's Goddard Space Flight Center manages the Living With a Star program of which the Van Allen Probes is a project, along with Solar Dynamics Observatory; the Applied Physics Laboratory is responsible for the implementation and instrument management for the Van Allen Probes. Radiation belts exist around other planets and moons in the solar system that have magnetic fields powerful enough to sustain them. To date, most of these radiation belts have been poorly mapped; the Voyager Program only nominally confirmed the existence of similar belts around Uranus and Neptune. The inner Van Allen Belt extends from an altitude of 0.2 to 2 Earth radii or 1,000 km to 6,000 km above the Earth.
In certain cases when solar activity is stronger or in geographical areas such as the South Atlantic Anomaly, the inner boundary may decline to 200 kilometers above the Earth's surface. The inner belt contains high concentrations of electrons in the range of hundreds of keV and energetic protons with energies exceeding 100 MeV, trapped by the strong magnetic fields in the region, it is believed that proton energies exceeding 50 MeV in the lower belts at lower altitudes are the result of the beta decay of neutrons created by cosmic ray collisions with nuclei of the upper atmosphere. The source of lower energy protons is believed to be proton diffusion due to changes in the magnetic field during geomagnetic storms. Due to the slight offset of the belts from Earth's geometric center, the inner Van Allen belt makes its closest approach to the surface at the South Atlantic Anomaly. On March 2014, a pattern resembling'zebra stripes' was observed in the radiation belts by the Radiation Belt Storm Probes Ion Composition Experiment onboard Van Allen Probes.
The reason reported was that due to the tilt in Earth's magnetic field axis, the planet’s rotation generated an oscillating, weak electric field that permeates through the entire inner radiation belt. It was demonstrated that the zebra stripes were in fact an imprint of ionospheric winds on radiation belts; the outer belt consists of high energy electrons trapped by the Earth's magnetosphere. It is more variable than the inner belt as it is more influenced by solar activity, it is toroidal in shape, beginning at an altitude of three and extending to ten Earth radii 13,000 to 60,000 kilometres above the Earth's surface. Its greatest intensity is around 4–5 RE; the outer electron radiation belt is produced by the inward radial diffusion and local acceleration due to transfer of energy from whistler-mode plasma waves to radiation belt electrons. Radiation belt electrons are constantly removed by collisions with Earth's atmosphere, losses to the magnetopause, their outward radial diffusion; the gyroradii of energetic protons would be large enough to bring them into contact with the Earth's atmosphere.
Within this belt, the electrons have a high flux and at the outer edge, w
Pioneer Venus project
The Pioneer Venus project was part of the Pioneer program consisting of two spacecraft, the Pioneer Venus Orbiter and the Pioneer Venus Multiprobe, launched to Venus in 1978. The program was managed by NASA's Ames Research Center. An official Ames documentary film titled "Venus Pioneers" is visible on George Van Valkenburg's YouTube Channel; the Pioneer Venus Orbiter entered orbit around Venus on December 4, 1978, performed observations to characterize the atmosphere and surface of Venus. It continued to transmit data until October 1992; the Pioneer Venus Multiprobe deployed four small probes into the Venusian atmosphere on December 9, 1978. All four probes transmitted data throughout their descent to the surface. One probe survived landing and transmitted data from the surface for over an hour; the Pioneer mission consisted of two components, launched separately: an orbiter and a multiprobe. The orbiter was launched on 20 May 1978 with an Atlas-Centaur rocket; the orbiter's mass was 517 kg. The Pioneer Venus Orbiter was inserted into an elliptical orbit around Venus on December 4, 1978.
It carried 17 experiments: a cloud photopolarimeter to measure the vertical distribution of the clouds a surface radar mapper to determine topography and surface characteristics an infrared radiometer to measure IR emissions from the Venus atmosphere an airglow ultraviolet spectrometer to measure scattered and emitted UV light a neutral mass spectrometer to determine the composition of the upper atmosphere a solar wind plasma analyzer to measure properties of the solar wind a magnetometer to characterize the magnetic field at Venus an electric field detector to study the solar wind and its interactions an electron temperature probe to study the thermal properties of the ionosphere an ion mass spectrometer to characterize the ionospheric ion population a charged particle retarding potential analyzer to study ionospheric particles two radio science experiments to determine the gravity field of Venus a radio occultation experiment to characterize the atmosphere an atmospheric drag experiment to study the upper atmosphere a radio science atmospheric and solar wind turbulence experiment a gamma ray burst detector to record gamma-ray burst eventsIn May 1992 the orbiter began the final phase of its mission, in which the periapsis was held between 150 and 250 km until the fuel ran out and atmospheric entry destroyed the spacecraft in August 1992.
The Pioneer Venus Multiprobe was launched on August 1978 on an Atlas-Centaur rocket. It consisted of a 290 kg bus; the large probe was released on November 16, 1978 and the three small probes on November 20. All four probes entered the Venus atmosphere followed by the bus; the Pioneer Venus large probe equipped with 7 science experiments. After deceleration from initial atmospheric entry at about 11.5 km/s, a parachute was deployed at 47 km altitude. The science experiments were: a neutral mass spectrometer to measure the atmospheric composition a gas chromatograph to measure the atmospheric composition a solar flux radiometer to measure solar flux penetration in the atmosphere an infrared radiometer to measure distribution of infrared radiation a cloud particle size spectrometer to measure particle size and shape a nephelometer to search for cloud particles temperature and acceleration sensorsThe three small probes were identical to each other, 0.8 m in diameter and 90 kg each small probe. The small probes were each targeted at different parts of the planet.
The Pioneer Venus bus carried two experiments, a neutral mass spectrometer and an ion mass spectrometer to study the composition of the atmosphere. With no heat shield or parachute, the bus made measurements only to about 110 km altitude before burning up. 1978 in spaceflight Vega program Venera program NASA: Pioneer Venus Project Information Pioneer Venus Program Page by NASA's Solar System Exploration NSSDC Master Catalog: Spacecraft Pioneer Venus Probe Bus. Pioneer Venus specifications at NASA "The Pioneer Venus Orbiter: 11 years of data." Results published in May 1, 1990. Art for the mission
Sputnik 2, or Prosteyshiy Sputnik 2 was the second spacecraft launched into Earth orbit, on 3 November 1957, the first to carry a living animal, a Soviet space dog named Laika, who died, a few hours after the launch. Launched by the U. S. S. R. Sputnik 2 was a 4-meter high cone-shaped capsule with a base diameter of 2 meters that weighed around 500 kg, though it was not designed to separate from the rocket core that brought it to orbit, bringing the total mass in orbit to 89 kilos, it contained several compartments for radio transmitters, a telemetry system, a programming unit, a regeneration and temperature-control system for the cabin, scientific instruments. A separate sealed cabin contained the dog Laika. Engineering and biological data were transmitted using the Tral D telemetry system, transmitting data to Earth for a 15-minute period during each orbit. Two photometers were on board for measuring cosmic rays. A 100 line television camera provided images of Laika. Sputnik 2 was launched into space only 32 days after its predecessor Sputnik 1.
Due to the huge success of Sputnik 1, Nikita Khrushchev ordered Sergey Korolev back to work creating a Sputnik 2 that needed to be ready for space for the 40th anniversary of the Bolshevik revolution. Sputnik 2 was part of an idea that included Sputnik 1 that came from Korolev, approved in January 1957. At that time, it was not clear that the Soviets' main satellite plan would be able to get to space because of the ongoing issues with the R-7 ICBM, which would be needed to launch a satellite of that size. “Korolev proposed substituting two'simple satellites' for the IGY satellite”. The choice to launch these two instead of waiting for the more advanced Sputnik 3 to be finished was motivated by the desire to launch a satellite to orbit before the US. Sputnik 2, known to Korolev's design bureau as "Prosteyshiy Sputnik-2", meaning "Simple Satellite 2", was launched into a 212 × 1660 km orbit with a period of 103.7 minutes on a modified ICBM R-7, similar to the one used to launch Sputnik 1. Sputnik 2's launch vehicle had several modifications for the mission.
These included modifying the launch trajectory to utilize propellant more efficiently and removing some flight control components to reduce weight. In addition, the core stage would be burned to propellant depletion instead of cutting off at a preset time; the telemetry system at engine cutoff would be switched from monitoring the booster's parameters to those of the capsule. It was designed to only transmit data for ten minutes at a time every 90 minutes, so as to prevent battery power from being used up sending data while the spacecraft was out of range of Soviet tracking stations; the interstage section between the booster and capsule was polished and equipped with thermal blankets so as to reflect off sunlight and keep the latter cool several deployable reflectors were mounted on the core stage. A braking nozzle was added to the core stage to prevent it from tumbling in orbit. Several RD-107 engines were test-fired, with the best-performing units being selected for use on Sputnik 2's booster.
The launch vehicle arrived at Baikonur on October 22, along with various parts of the capsule. On November 1, the booster was erected on LC-1. Ten dogs were considered for the mission, with the final selection being narrowed down to three, Laika being the flight animal, Albina the backup, Muhka, used to test equipment. Liftoff took place at about 5:30 PM Moscow time on November 3. Booster performance was nominal and the command to terminate core stage thrust was issued at T+297 seconds, just as onboard sensors detected LOX depletion; the booster and capsule entered a 225 km × 1,671 km orbit at a 65 degree inclination. During the first two orbits, it proved difficult to reliably track Sputnik 2's flight path, but ground controllers were able to intercept theodolite data from an American tracking station in Perth, Australia. Data showed that Laika's heart rate and breathing spiked during ascent, but she otherwise reached orbit unscathed. Official Soviet press releases stated that Laika survived a week in orbit, but information released in the post-Soviet era indicated that she died only a few hours into the mission.
Other sources suggested it had been four days before the dog succumbed to overheating and carbon dioxide buildup. Telemetry data indicated that Laika's vital signs were normal for the first three orbits, but during the fourth orbit, the cabin temperature rose to 43 °C followed by movements of the dog. Data received on the second day showed no signs of breathing, heart rate, or blood pressure, but the cardio sensor was still registering a heart beat. By the morning of November 6, there were no signs of life in the capsule. On November 10, the batteries in the spacecraft ran out and all data transmission ceased, after 150 separate telemetry sessions. Sputnik 2 reentered the atmosphere on April 1958 after 162 days in space and about 2500 orbits. Reentry was sighted from the east coast of the United States and surviving debris impacted in the Amazon region of South America; the flight sparked considerable ethical debate about cruelty to animals, as Laika had been launched with the full knowledge that she could not be recovered and may have suffered a quite unpleasant death from panic and overheating, some Soviet space program officials felt sorry about her.
An anonymously-written poem criticizing the mission and the Soviet state was
Earth is the third planet from the Sun and the only astronomical object known to harbor life. According to radiometric dating and other sources of evidence, Earth formed over 4.5 billion years ago. Earth's gravity interacts with other objects in space the Sun and the Moon, Earth's only natural satellite. Earth revolves around the Sun in a period known as an Earth year. During this time, Earth rotates about its axis about 366.26 times. Earth's axis of rotation is tilted with respect to its orbital plane; the gravitational interaction between Earth and the Moon causes ocean tides, stabilizes Earth's orientation on its axis, slows its rotation. Earth is the largest of the four terrestrial planets. Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earth's surface is covered with water by oceans; the remaining 29% is land consisting of continents and islands that together have many lakes and other sources of water that contribute to the hydrosphere.
The majority of Earth's polar regions are covered in ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the Earth's magnetic field, a convecting mantle that drives plate tectonics. Within the first billion years of Earth's history, life appeared in the oceans and began to affect the Earth's atmosphere and surface, leading to the proliferation of aerobic and anaerobic organisms; some geological evidence indicates. Since the combination of Earth's distance from the Sun, physical properties, geological history have allowed life to evolve and thrive. In the history of the Earth, biodiversity has gone through long periods of expansion punctuated by mass extinction events. Over 99% of all species that lived on Earth are extinct. Estimates of the number of species on Earth today vary widely. Over 7.6 billion humans live on Earth and depend on its biosphere and natural resources for their survival.
Humans have developed diverse cultures. The modern English word Earth developed from a wide variety of Middle English forms, which derived from an Old English noun most spelled eorðe, it has cognates in every Germanic language, their proto-Germanic root has been reconstructed as *erþō. In its earliest appearances, eorðe was being used to translate the many senses of Latin terra and Greek γῆ: the ground, its soil, dry land, the human world, the surface of the world, the globe itself; as with Terra and Gaia, Earth was a personified goddess in Germanic paganism: the Angles were listed by Tacitus as among the devotees of Nerthus, Norse mythology included Jörð, a giantess given as the mother of Thor. Earth was written in lowercase, from early Middle English, its definite sense as "the globe" was expressed as the earth. By Early Modern English, many nouns were capitalized, the earth became the Earth when referenced along with other heavenly bodies. More the name is sometimes given as Earth, by analogy with the names of the other planets.
House styles now vary: Oxford spelling recognizes the lowercase form as the most common, with the capitalized form an acceptable variant. Another convention capitalizes "Earth" when appearing as a name but writes it in lowercase when preceded by the, it always appears in lowercase in colloquial expressions such as "what on earth are you doing?" The oldest material found in the Solar System is dated to 4.5672±0.0006 billion years ago. By 4.54±0.04 Bya the primordial Earth had formed. The bodies in the Solar System evolved with the Sun. In theory, a solar nebula partitions a volume out of a molecular cloud by gravitational collapse, which begins to spin and flatten into a circumstellar disk, the planets grow out of that disk with the Sun. A nebula contains gas, ice grains, dust. According to nebular theory, planetesimals formed by accretion, with the primordial Earth taking 10–20 million years to form. A subject of research is the formation of some 4.53 Bya. A leading hypothesis is that it was formed by accretion from material loosed from Earth after a Mars-sized object, named Theia, hit Earth.
In this view, the mass of Theia was 10 percent of Earth, it hit Earth with a glancing blow and some of its mass merged with Earth. Between 4.1 and 3.8 Bya, numerous asteroid impacts during the Late Heavy Bombardment caused significant changes to the greater surface environment of the Moon and, by inference, to that of Earth. Earth's atmosphere and oceans were formed by volcanic outgassing. Water vapor from these sources condensed into the oceans, augmented by water and ice from asteroids and comets. In this model, atmospheric "greenhouse gases" kept the oceans from freezing when the newly forming Sun had only 70% of its current luminosity. By 3.5 Bya, Earth's magnetic field was established, which helped prevent the atmosphere from being stripped away by the solar wind. A crust formed; the two models that explain land mass propose either a steady growth to the present-day forms or, more a rapid growth early in Earth history followed by a long-term steady continental area. Continents formed by plate tectonics
Africa is the world's second largest and second most-populous continent, being behind Asia in both categories. At about 30.3 million km2 including adjacent islands, it covers 6% of Earth's total surface area and 20% of its land area. With 1.2 billion people as of 2016, it accounts for about 16% of the world's human population. The continent is surrounded by the Mediterranean Sea to the north, the Isthmus of Suez and the Red Sea to the northeast, the Indian Ocean to the southeast and the Atlantic Ocean to the west; the continent includes various archipelagos. It contains 54 recognised sovereign states, nine territories and two de facto independent states with limited or no recognition; the majority of the continent and its countries are in the Northern Hemisphere, with a substantial portion and number of countries in the Southern Hemisphere. Africa's average population is the youngest amongst all the continents. Algeria is Africa's largest country by area, Nigeria is its largest by population. Africa central Eastern Africa, is accepted as the place of origin of humans and the Hominidae clade, as evidenced by the discovery of the earliest hominids and their ancestors as well as ones that have been dated to around 7 million years ago, including Sahelanthropus tchadensis, Australopithecus africanus, A. afarensis, Homo erectus, H. habilis and H. ergaster—the earliest Homo sapiens, found in Ethiopia, date to circa 200,000 years ago.
Africa encompasses numerous climate areas. Africa hosts a large diversity of ethnicities and languages. In the late 19th century, European countries colonised all of Africa. African nations cooperate through the establishment of the African Union, headquartered in Addis Ababa. Afri was a Latin name used to refer to the inhabitants of then-known northern Africa to the west of the Nile river, in its widest sense referred to all lands south of the Mediterranean; this name seems to have referred to a native Libyan tribe, an ancestor of modern Berbers. The name had been connected with the Phoenician word ʿafar meaning "dust", but a 1981 hypothesis has asserted that it stems from the Berber word ifri meaning "cave", in reference to cave dwellers; the same word may be found in the name of the Banu Ifran from Algeria and Tripolitania, a Berber tribe from Yafran in northwestern Libya. Under Roman rule, Carthage became the capital of the province it named Africa Proconsularis, following its defeat of the Carthaginians in the Third Punic War in 146 BC, which included the coastal part of modern Libya.
The Latin suffix -ica can sometimes be used to denote a land. The Muslim region of Ifriqiya, following its conquest of the Byzantine Empire's Exarchatus Africae preserved a form of the name. According to the Romans, Africa lay to the west of Egypt, while "Asia" was used to refer to Anatolia and lands to the east. A definite line was drawn between the two continents by the geographer Ptolemy, indicating Alexandria along the Prime Meridian and making the isthmus of Suez and the Red Sea the boundary between Asia and Africa; as Europeans came to understand the real extent of the continent, the idea of "Africa" expanded with their knowledge. Other etymological hypotheses have been postulated for the ancient name "Africa": The 1st-century Jewish historian Flavius Josephus asserted that it was named for Epher, grandson of Abraham according to Gen. 25:4, whose descendants, he claimed, had invaded Libya. Isidore of Seville in his 7th-century Etymologiae XIV.5.2. Suggests "Africa comes from the Latin aprica, meaning "sunny".
Massey, in 1881, stated that Africa is derived from the Egyptian af-rui-ka, meaning "to turn toward the opening of the Ka." The Ka is the energetic double of every person and the "opening of the Ka" refers to a womb or birthplace. Africa would be, for the Egyptians, "the birthplace." Michèle Fruyt in 1976 proposed linking the Latin word with africus "south wind", which would be of Umbrian origin and mean "rainy wind". Robert R. Stieglitz of Rutgers University in 1984 proposed: "The name Africa, derived from the Latin *Aphir-ic-a, is cognate to Hebrew Ophir." Ibn Khallikan and some other historians claim that the name of Africa came from a Himyarite king called Afrikin ibn Kais ibn Saifi called "Afrikus son of Abrahah" who subdued Ifriqiya. Africa is considered by most paleoanthropologists to be the oldest inhabited territory on Earth, with the human species originating from the continent. During the mid-20th century, anthropologists discovered many fossils and evidence of human occupation as early as 7 million years ago.
Fossil remains of several species of early apelike humans thought to have evolved into modern man, such as Australopithecus afarensis (radiometrically dated to 3.9–3.0 million years BP, Paranthropus boisei and Homo ergaster have been discovered. After the evolution of Homo sapiens sapiens 150,000 to 100,000 years BP in Africa, the continent was populated by groups of hunter-gatherers; these first modern humans left Africa and populated the rest of the globe during the Out of Africa II migration dated to 50,000 years BP, exiting the continent eith
Pioneer Venus Orbiter
The Pioneer Venus Orbiter known as Pioneer Venus 1 or Pioneer 12, was a mission to Venus conducted by the United States as part of the Pioneer Venus project. Launched in May 1978 atop an Atlas-Centaur rocket, the spacecraft was inserted into an elliptical orbit around Venus on December 4, 1978, it returned data on Venus until October 1992. The Pioneer Venus Orbiter was launched by an Atlas SLV-3D Centaur-D1AR rocket, which flew from Launch Complex 36A at the Cape Canaveral Air Force Station; the launch occurred at 13:13:00 on May 20, 1978, deployed the Orbiter into heliocentric orbit for its coast to Venus. Venus orbit insertion occurred on December 4, 1978. Manufactured by Hughes Aircraft Company, the Pioneer Venus Orbiter was based on the HS-507 bus; the spacecraft was 2.5 meters in diameter and 1.2 meters long. All instruments and spacecraft subsystems were mounted on the forward end of the cylinder, except the magnetometer, at the end of a 4.7 meters boom. A solar array extended around the circumference of the cylinder.
A 1.09 metres despun dish antenna provided X band communication with Earth. A Star-24 solid rocket motor was integrated into the spacecraft to provide the thrust to enter orbit around Venus. From Venus orbit insertion to July 1980, periapsis was held between 142 and 253 kilometres to facilitate radar and ionospheric measurements; the spacecraft was in a 24-hour orbit with an apoapsis of 66,900 kilometers. Thereafter, the periapsis was allowed to rise to a maximum of 2,290 kilometres and fall, to conserve fuel. In 1991, the Radar Mapper was reactivated to investigate inaccessible southern portions of the planet, in conjunction with the arrived Magellan spacecraft. In May 1992, Pioneer Venus began the final phase of its mission, in which the periapsis was held between 150 and 250 kilometres, until the spacecraft's propellant was exhausted, after which the orbit decayed naturally; the spacecraft continued to return data until 8 October 1992, with the last signals being received at 19:22 UTC. The Pioneer Venus Orbiter disintegrated upon entering the atmosphere of Venus on October 22, 1992.
The Pioneer Venus Orbiter carried 17 experiments with a total mass of 45 kilograms: a cloud photo-polarimeter to measure the vertical distribution of the clouds, similar to Pioneer 10 and Pioneer 11 imaging photo-polarimeter a surface radar mapper to determine topography and surface characteristics. Observations could only be conducted. A 20 Watt S-band signal was sent to the surface that reflected it, with the probe analyzing the echo. Resolution at periapsis was 23 x 7 km. an infrared radiometer to measure IR emissions from Venus' atmosphere an airglow ultraviolet spectrometer to measure scattered and emitted UV light a neutral mass spectrometer to determine the composition of the upper atmosphere a solar wind plasma analyzer to measure properties of the solar wind a magnetometer to characterize the magnetic field at Venus an electric field detector to study the solar wind and its interactions an electron temperature to study the thermal properties of the ionosphere an ion mass spectrometer to characterize the ionospheric ion population a charged particle retarding potential analyzer to study ionospheric particles two radio science experiments to determine the gravity field of Venus a radio occultation experiment to characterize the atmosphere an atmospheric drag experiment to study the upper atmosphere a radio science atmospheric and solar wind turbulence experiment a gamma ray burst detector to record gamma ray burst events The spacecraft conducted radar altimetry observations allowing the first global topographic map of the Venusian surface to be constructed.
From its orbit of Venus, the Pioneer Venus Orbiter was able to observe Halley's Comet when it was unobservable from Earth due to its proximity to the sun during February 1986. UV spectrometer observations monitored the loss of water from the comet's nucleus at perihelion on February 9. Pioneer Venus Multiprobe List of missions to Venus Timeline of artificial satellites and space probes NASA: Pioneer Venus Project Information Pioneer Venus Program Page by NASA's Solar System Exploration Kasprzak, W. T – The Pioneer Venus Orbiter: 11 years of data. – NASA Donahue, T. M.. "Pioneer Venus Results: An Overview". Science. 205: 41–44. Bibcode:1979Sci...205...41D. Doi:10.1126/science.205.4401.41. JSTOR 1748508. Colin, Lawrence. "Encounter with Venus: An Update". Science. 205: 44–46. Bibcode:1979Sci...205...44C. doi:10.1126/science.205.4401.44. JSTOR 1748509. Seiff, Alvin. "Thermal Contrast in the Atmosphere of Venus: Initial Appraisal from Pioneer Venus Probe Data". Science. 205: 46–49. Bibcode:1979Sci...205...46S.
Doi:10.1126/science.205.4401.46. JSTOR 1748510. Hoffman, J. H.. "Composition and Structure of the Venus Atmosphere: Results from Pioneer Venus". Science. 205: 49–52. Bibcode:1979Sci...205...49H. Doi:10.1126/science.205.4401.49. JSTOR 1748511. PMID 17778898. Oyama, V. I.. B.. "Laboratory Corroboration of the Pioneer Venus Gas Chromatograph Analyses". Science. 205: 52–54. Bibcode:1979Sci...205...52O. Doi:10.1126/science.205.4401.52. JSTOR 1748512. Niemann, H. B.. (
National Aeronautics and Space Act
The National Aeronautics and Space Act of 1958 is the United States federal statute that created the National Aeronautics and Space Administration. The Act, which followed close on the heels of the Soviet Union's launch of Sputnik, was drafted by the United States House Select Committee on Astronautics and Space Exploration and on July 29, 1958 was signed by President Eisenhower. Prior to enactment, the responsibility for space exploration was deemed a military venture, in line with the Soviet model that had launched the first orbital satellite. In large measure, the Act was prompted by the lack of response by a US military infrastructure that seemed incapable of keeping up the space race; the original 1958 act charged the new Agency with conducting the aeronautical and space activities of the United States "so as to contribute materially to one or more of the following objectives:" The expansion of human knowledge of phenomena in the atmosphere and space. The preservation of the role of the United States as a leader in aeronautical and space science and technology and in the application thereof to the conduct of peaceful activities within and outside the atmosphere.
The making available to agencies directly concerned with national defenses of discoveries that have military value or significance, the furnishing by such agencies, to the civilian agency established to direct and control nonmilitary aeronautical and space activities, of information as to discoveries which have value or significance to that agency. In 2012, a ninth objective was added: The preservation of the United States preeminent position in aeronautics and space through research and technology development related to associated manufacturing processes; the Act abolished the National Advisory Committee for Aeronautics, transferring its activities and resources to NASA effective October 1, 1958. The Act created a Civilian-Military Liaison Committee, for the purpose of coordinating civilian and military space applications, keeping NASA and the Department of Defense "fully and informed" of each other's space activities. To this day, the United States has coordinated but separate military and civilian space programs, with much of the former involved in launching military and surveillance craft and, prior to the Partial Test Ban Treaty, planning counter-measures to the anticipated Soviet launch of nuclear warheads into space.
In addition, the new law made extensive modifications to the patent law and provided that both employee inventions as well as private contractor innovations brought about through space travel would be subject to government ownership. By making the government the exclusive provider of space transport, the act discouraged the private development of space travel; this situation endured until the law was modified by the Commercial Space Launch Act of 1984, enacted to allow civilian use of NASA systems in launching space vehicles. The phrase "We came in peace for all mankind", inscribed on a plaque left on the Moon by the crew of Apollo 11, is derived from the Act's declaration of NASA's policy and purpose: The Congress hereby declares that it is the policy of the United States that activities in space should be devoted to peaceful purposes for the benefit of all mankind; the Act was subsequently amended to remove gender bias, so that this policy statement now reads: Devotion of Space Activities to Peaceful Purposes for Benefit of All Humankind.--Congress declares that it is the policy of the United States that activities in space should be devoted to peaceful purposes for the benefit of all humankind.
Spinoff history Text of the National Aeronautics and Space Act, via NASA.gov Overview of Congressional Committee testimony prior to enactment Dwight D. Eisenhower memorandum to Defense Department regarding creation of NASA and military's role History of U. S. national space policy