1.
European Space Agency
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The European Space Agency is an intergovernmental organisation of 22 member states, dedicated to the exploration of space. Established in 1975 and headquartered in Paris, France, ESA has a staff of about 2,000. The main European launch vehicle Ariane 5 is operated through Arianespace with ESA sharing in the costs of launching, after World War II, many European scientists left Western Europe in order to work with the United States. The meeting was attended by representatives from eight countries, including Harrie Massey. The Western European nations decided to have two different agencies, one concerned with developing a system, ELDO, and the precursor of the European Space Agency. The latter was established on 20 March 1964 by an agreement signed on 14 June 1962, from 1968 to 1972, ESRO launched seven research satellites. ESA in its current form was founded with the ESA Convention in 1975, ESA has 10 founding member states, Belgium, Denmark, France, Germany, Italy, the Netherlands, Spain, Sweden, Switzerland and the United Kingdom. These signed the ESA Convention in 1975 and deposited the instruments of ratification by 1980, during this interval the agency functioned in a de facto fashion. ESA launched its first major scientific mission in 1975, Cos-B, ESA joined NASA in the IUE, the worlds first high-orbit telescope, which was launched in 1978 and operated very successfully for 18 years. A number of successful Earth-orbit projects followed, and in 1986 ESA began Giotto, its first deep-space mission, to study the comets Halley and Grigg–Skjellerup. Hipparcos, a mission, was launched in 1989 and in the 1990s SOHO, Ulysses. Recent scientific missions in co-operation with NASA include the Cassini–Huygens space probe, as the successor of ELDO, ESA has also constructed rockets for scientific and commercial payloads. Ariane 1, launched in 1979, brought mostly commercial payloads into orbit from 1984 onward, the successor launch vehicle of Ariane 5, the Ariane 6 is already in the definition stage and is envisioned to enter service in the 2020s. The beginning of the new millennium saw ESA become, along with agencies like NASA, JAXA, ISRO, CSA and Roscosmos, one of the major participants in scientific space research. Although ESA had relied on co-operation with NASA in previous decades, especially the 1990s, changed circumstances led to decisions to rely more on itself, a 2011 press issue thus stated, Russia is ESAs first partner in its efforts to ensure long-term access to space. ESA maintains its scientific and research projects mainly for astronomy-space missions such as Corot, launched on 27 December 2006 and this is the reason space exploration is an integral part of overall space activities. It has always been so, and it will be more important in the future. ESA describes its work in two overlapping ways, For the general public the various fields of work are described as Activities, Member states participate to varying degrees in the mandatory and optional space programmes
2.
Airbus Defence and Space
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Airbus Defence and Space is a division of Airbus Group responsible for defence and aerospace products and services. The division was formed in January 2014 during the restructuring of European Aeronautic Defence and Space, and comprises the former Airbus Military, Astrium. It is the second largest space company after Boeing and one of the top ten defence companies in the world. Airbus Defence and Space has its headquarters in Toulouse, France, and is led by Dirk Hoke. The company is divided into three sections, Military Aircraft, Space Systems, and Communication-Intelligence-Security, with its presence in 35 countries, the company employs 40,000 people from 86 nationalities and contributes to 21% of Airbus Group revenues. In 2015 Airbus ranked 100th on the Fortune Global 500 list, the two companies envisaged including the French company Aérospatiale, the other major European aerospace company, but only after its privatisation. The first stage of integration was seen as the transformation of Airbus from a consortium of British Aerospace, DASA, Aérospatiale. The merger of British Aerospace and MES to form BAE Systems was announced on 19 January 1999, DASA and the Spanish aircraft company Construcciones Aeronáuticas SA agreed to merge on 11 June 1999. On 14 October 1999 DASA agreed to merge with Aérospatiale-Matra to create the European Aeronautic Defence and Space Company,10 July 2000 was Day One for the new company which became the worlds second-largest aerospace company after Boeing and the second-largest European arms manufacturer after BAE Systems. In January 2001 Airbus Industrie was transformed from an inherently inefficient consortium structure to a joint stock company, with legal. On 16 June 2003 EADS acquired BAEs 25 % share in Astrium, EADS paid £84 million, however due to the lossmaking status of the company BAE invested an equal amount for restructuring. It was subsequently renamed EADS Astrium, and had the divisions Astrium Satellites, Astrium Space Transportation, on 1 July 2003 EADS Defence & Security Systems was founded with the merger of the activities of missile systems, defence electronics, military aircraft and telecommunications of the EADS Group. Tom Enders became the first CEO of the new division, the predecessor company was established in January 1999 as the Airbus Military Company SAS to manage the Airbus A400M project, taking over from the Euroflag consortium. In May 2003, the company was restructured as Airbus Military Sociedad Limitada prior to the execution of the production contract, the Military Transport Aircraft Division was a division of EADS which designs, manufactures and commercialises EADS-CASA light and medium transport aircraft, and headquartered in Madrid, Spain. In 1999 was Construcciones Aeronáuticas SA in the EADS Group incorporated, in Spain it was still referred to as EADS-CASA. The division manufactured tanker, transport and mission aircraft including Airbus A330 MRTT, Airbus A400M, CASA C-212 Aviocar, CASA/IPTN CN-235, after the merger, it also acquired the production of Eurofighter Typhoon, which was earlier under Cassidian. Eurocopter, which was earlier under Airbus Military, was reorganized as Airbus Helicopters, Astrium was formed in 2000 by the merger of Matra Marconi Space with the space division of DaimlerChrysler Aerospace AG and Computadores Redes e Ingeniería SA. Henceforth Astrium was a joint venture between EADS and BAE Systems, on 16 June 2003 the minority shareholder, BAE Systems, sold its 25% share to EADS, making EADS the sole shareholder
3.
Guiana Space Centre
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The Guiana Space Centre or, more commonly, Centre Spatial Guyanais is a French and European spaceport to the northwest of Kourou in French Guiana. The European Space Agency, the French space agency CNES, and this was the spaceport used by the ESA to send supplies to the International Space Station using the Automated Transfer Vehicle. The location was selected in 1964 to become the spaceport of France, in 1975, France offered to share Kourou with ESA. Commercial launches are bought also by non-European companies, ESA pays two thirds of the spaceports annual budget and has also financed the upgrades made during the development of the Ariane launchers. Since April 4,2017, the centre has been occupied by 30 labor union leaders in the midst of the 2017 social unrest in French Guiana, Kourou is located approximately 500 kilometres north of the equator, at a latitude of 5°10. The near-equatorial launch location provides an advantage for launches to low-inclination Earth orbits compared to launches from spaceports at higher latitude, the proximity to the equator also makes maneuvering satellites for geosynchronous orbits simpler and less costly. Originally built in the 1960s under the name of CECLES, the ELV pad located at 5. 236°N52. 775°W /5.236, one Europa-II was launched from the site, before the programme was cancelled. The pad was demolished, and subsequently rebuilt as the first launch complex for Ariane rockets, renamed ELA, it was used for Ariane 1 and Ariane 2 and 3 launches until being retired in 1989. It was again refurbished for the Vega with the first launch performed on 13 February 2012, the ELA2 pad, located at 5. 232°N52. 776°W /5.232, -52.776 had been used for Ariane 4 launches until 2003. ELA3 has been active for Ariane 5 launches since 1996 and this facility is located at 5. 239°N52. 768°W /5.239, -52.768 and covers an area of 21 square kilometres. ESA has built ELS at 5. 305°N52. 834°W /5.305, the first Soyuz launch from ELS was postponed several times, but launched on October 21,2011. ELS is located on the territory of Sinnamary commune,27 km from Kourou harbor and it is 10 km north of the site used for the Ariane 5 launches. Russia will use the Guiana Space Centre in addition to Baikonur Cosmodrome, the Guiana location has the significant benefit of greatly increased payload capability, owing to the near equatorial position. A Soyuz rocket with a 1.7 tonnes to geostationary transfer orbit performance from Baikonur, the ELS project is being co-funded by Arianespace, ESA, and the European Union, with CNES being the prime contractor. The project has a projected cost of approximately €320 million, where €120 million are allocated for modernizing the Soyuz vehicle, the official opening of the launch site construction occurred on 27 February 2007. Excavation work however, had begun several months beforehand. By October 2010,18 launch contracts had been signed, Arianespace has ordered 24 launchers from Russian industry. On October 21,2011, two Galileo IOV-1 & IOV-2 satellites were launched using a Soyuz-ST rocket, in the first Russian Soyuz vehicle ever launched from Europes Spaceport in French Guiana, astrium assembles each Ariane 5 launcher in the Launcher Integration Building
4.
Greek mythology
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It was a part of the religion in ancient Greece. Greek mythology is explicitly embodied in a collection of narratives. Greek myth attempts to explain the origins of the world, and details the lives and adventures of a variety of gods, goddesses, heroes, heroines. These accounts initially were disseminated in a tradition, today the Greek myths are known primarily from ancient Greek literature. The oldest known Greek literary sources, Homers epic poems Iliad and Odyssey, focus on the Trojan War, archaeological findings provide a principal source of detail about Greek mythology, with gods and heroes featured prominently in the decoration of many artifacts. Geometric designs on pottery of the eighth century BC depict scenes from the Trojan cycle as well as the adventures of Heracles, in the succeeding Archaic, Classical, and Hellenistic periods, Homeric and various other mythological scenes appear, supplementing the existing literary evidence. Greek mythology has had an influence on the culture, arts. Poets and artists from ancient times to the present have derived inspiration from Greek mythology and have discovered contemporary significance and relevance in the themes, Greek mythology is known today primarily from Greek literature and representations on visual media dating from the Geometric period from c. Mythical narration plays an important role in every genre of Greek literature. Nevertheless, the only general mythographical handbook to survive from Greek antiquity was the Library of Pseudo-Apollodorus and this work attempts to reconcile the contradictory tales of the poets and provides a grand summary of traditional Greek mythology and heroic legends. Apollodorus of Athens lived from c, 180–125 BC and wrote on many of these topics. His writings may have formed the basis for the collection, however the Library discusses events that occurred long after his death, among the earliest literary sources are Homers two epic poems, the Iliad and the Odyssey. Other poets completed the cycle, but these later and lesser poems now are lost almost entirely. Despite their traditional name, the Homeric Hymns have no connection with Homer. They are choral hymns from the part of the so-called Lyric age. Hesiods Works and Days, a poem about farming life, also includes the myths of Prometheus, Pandora. The poet gives advice on the best way to succeed in a dangerous world, lyrical poets often took their subjects from myth, but their treatment became gradually less narrative and more allusive. Greek lyric poets, including Pindar, Bacchylides and Simonides, and bucolic poets such as Theocritus and Bion, additionally, myth was central to classical Athenian drama
5.
Atmosphere of Earth
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The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earths gravity. The atmosphere of Earth protects life on Earth by absorbing solar radiation, warming the surface through heat retention. By volume, dry air contains 78. 09% nitrogen,20. 95% oxygen,0. 93% argon,0. 04% carbon dioxide, and small amounts of other gases. Air also contains an amount of water vapor, on average around 1% at sea level. The atmosphere has a mass of about 5. 15×1018 kg, the atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. The Kármán line, at 100 km, or 1. 57% of Earths radius, is used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km, several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition. The study of Earths atmosphere and its processes is called atmospheric science, early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann. The three major constituents of air, and therefore of Earths atmosphere, are nitrogen, oxygen, water vapor accounts for roughly 0. 25% of the atmosphere by mass. The remaining gases are often referred to as gases, among which are the greenhouse gases, principally carbon dioxide, methane, nitrous oxide. Filtered air includes trace amounts of other chemical compounds. Various industrial pollutants also may be present as gases or aerosols, such as chlorine, fluorine compounds, sulfur compounds such as hydrogen sulfide and sulfur dioxide may be derived from natural sources or from industrial air pollution. In general, air pressure and density decrease with altitude in the atmosphere, however, temperature has a more complicated profile with altitude, and may remain relatively constant or even increase with altitude in some regions. In this way, Earths atmosphere can be divided into five main layers, excluding the exosphere, Earth has four primary layers, which are the troposphere, stratosphere, mesosphere, and thermosphere. It extends from the exobase, which is located at the top of the thermosphere at an altitude of about 700 km above sea level, to about 10,000 km where it merges into the solar wind. This layer is composed of extremely low densities of hydrogen, helium and several heavier molecules including nitrogen, oxygen. The atoms and molecules are so far apart that they can travel hundreds of kilometers without colliding with one another, thus, the exosphere no longer behaves like a gas, and the particles constantly escape into space. These free-moving particles follow ballistic trajectories and may migrate in and out of the magnetosphere or the solar wind, the exosphere is located too far above Earth for any meteorological phenomena to be possible
6.
Low-pressure area
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A low-pressure area, low, or depression is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure systems form under areas of wind divergence that occur in the levels of the troposphere. The formation process of an area is known as cyclogenesis. Within the field of meteorology, atmospheric divergence aloft occurs in two areas, the first area is on the east side of upper troughs, which form half of a Rossby wave within the Westerlies. A second area of wind divergence aloft occurs ahead of embedded shortwave troughs, diverging winds aloft ahead of these troughs cause atmospheric lift within the troposphere below, which lowers surface pressures as upward motion partially counteracts the force of gravity. Thermal lows form due to localized heating caused by greater sunshine over deserts, since localized areas of warm air are less dense than their surroundings, this warmer air rises, which lowers atmospheric pressure near that portion of the Earths surface. Large-scale thermal lows over continents help drive monsoon circulations, low-pressure areas can also form due to organized thunderstorm activity over warm water. When this occurs over the tropics in concert with the Intertropical Convergence Zone, Monsoon troughs reach their northerly extent in August and their southerly extent in February. When a convective low acquires a well-hot circulation in the tropics it is termed a tropical cyclone, Tropical cyclones can form during any month of the year globally, but can occur in either the northern or southern hemisphere during November. Since clouds reflect sunlight, incoming solar radiation decreases, which causes lower temperatures during the day. At night the effect of clouds on outgoing longwave radiation, such as heat energy from the surface. The stronger the area of low pressure, the stronger the winds experienced in its vicinity, globally, low-pressure systems are most frequently located over the Tibetan Plateau and in the lee of the Rocky mountains. In Europe, recurring low-pressure weather systems are known as depressions. Cyclogenesis is the development and strengthening of cyclonic circulations, or low-pressure areas, cyclogenesis is the opposite of cyclolysis, and has an anticyclonic equivalent which deals with the formation of high-pressure areas—anticyclogenesis. Cyclogenesis is a term for several different processes, all of which result in the development of some sort of cyclone. Meteorologists use the term cyclone where circular pressure systems flow in the direction of the Earths rotation, the largest low-pressure systems are cold-core polar cyclones and extratropical cyclones which lie on the synoptic scale. Warm-core cyclones such as cyclones, mesocyclones, and polar lows lie within the smaller mesoscale. Subtropical cyclones are of intermediate size, cyclogenesis can occur at various scales, from the microscale to the synoptic scale
7.
Global warming
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Global warming and climate change are terms for the observed century-scale rise in the average temperature of the Earths climate system and its related effects. Multiple lines of evidence show that the climate system is warming. The largest human influence has been emission of gases such as carbon dioxide, methane. These findings have been recognized by the science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing. Future climate change and associated impacts will differ from region to region around the globe, anticipated effects include warming global temperature, rising sea levels, changing precipitation, and expansion of deserts in the subtropics. Warming is expected to be greater over land than over the oceans and greatest in the Arctic, with the retreat of glaciers, permafrost. Effects significant to humans include the threat to security from decreasing crop yields. Possible societal responses to global warming include mitigation by emissions reduction, adaptation to its effects, building systems resilient to its effects, most countries are parties to the United Nations Framework Convention on Climate Change, whose ultimate objective is to prevent dangerous anthropogenic climate change. Public reactions to global warming and concern about its effects are also increasing, a global 2015 Pew Research Center report showed a median of 54% consider it a very serious problem. There are significant regional differences, with Americans and Chinese among the least concerned, the global average surface temperature shows a warming of 0.85 °C in the period 1880 to 2012, based on multiple independently produced datasets. Earths average surface temperature rose by 0. 74±0.18 °C over the period 1906–2005, the rate of warming almost doubled for the last half of that period. The rest has melted ice and warmed the continents and atmosphere, the average temperature of the lower troposphere has increased between 0.12 and 0.135 °C per decade since 1979, according to satellite temperature measurements. The warming that is evident in the temperature record is consistent with a wide range of observations. The probability that these changes could have occurred by chance is virtually zero, temperature changes vary over the globe. Since 1979, land temperatures have increased about twice as fast as ocean temperatures, ocean temperatures increase more slowly than land temperatures because of the larger effective heat capacity of the oceans and because the ocean loses more heat by evaporation. Since the beginning of industrialisation the temperature difference between the hemispheres has increased due to melting of sea ice and snow in the North. Average arctic temperatures have been increasing at almost twice the rate of the rest of the world in the past 100 years, the thermal inertia of the oceans and slow responses of other indirect effects mean that climate can take centuries or longer to adjust to changes in forcing. Some of this warming will be driven by past natural forcings which are still seeking equilibrium in the climate system
8.
Air pollution
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Air pollution occurs when harmful substances including particulates and biological molecules are introduced into Earths atmosphere. It may cause diseases, allergies or death in humans, it may cause harm to other living organisms such as animals and food crops. Human activity and natural processes can both generate air pollution, indoor air pollution and poor urban air quality are listed as two of the worlds worst toxic pollution problems in the 2008 Blacksmith Institute Worlds Worst Polluted Places report. According to the 2014 WHO report, air pollution in 2012 caused the deaths of around 7 million people worldwide, an air pollutant is a substance in the air that can have adverse effects on humans and the ecosystem. The substance can be particles, liquid droplets, or gases. A pollutant can be of natural origin or man-made, pollutants are classified as primary or secondary. Primary pollutants are usually produced from a process, such as ash from a volcanic eruption, other examples include carbon monoxide gas from motor vehicle exhaust, or the sulfur dioxide released from factories. Secondary pollutants are not emitted directly, rather, they form in the air when primary pollutants react or interact. Ground level ozone is a prominent example of a secondary pollutant, some pollutants may be both primary and secondary, they are both emitted directly and formed from other primary pollutants. Substances emitted into the atmosphere by human activity include, Carbon dioxide - Debate continues over whether carbon dioxide should be classified as an atmospheric pollutant, because of its role as a greenhouse gas it has been described as the leading pollutant and the worst climate pollution. Against this it is argued that carbon dioxide is a component of the atmosphere, essential for plant life. This question of terminology has practical effects, for example as determining whether the U. S. Clean Air Act is deemed to regulate CO2 emissions, CO2 increase in earths atmosphere has been accelerating. Sulfur oxides - particularly sulfur dioxide, a compound with the formula SO2. SO2 is produced by volcanoes and in industrial processes. Coal and petroleum often contain sulfur compounds, and their combustion generates sulfur dioxide, further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and thus acid rain. This is one of the causes for concern over the impact of the use of these fuels as power sources. Nitrogen oxides - Nitrogen oxides, particularly nitrogen dioxide, are expelled from high temperature combustion and they can be seen as a brown haze dome above or a plume downwind of cities. Nitrogen dioxide is a compound with the formula NO2
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Wind
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Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the movement of air. Winds are commonly classified by their scale, their speed, the types of forces that cause them, the regions in which they occur. The strongest observed winds on a planet in the Solar System occur on Neptune, Winds have various aspects, an important one being its velocity, another the density of the gas involved, another its energy content or wind energy. In meteorology, winds are referred to according to their strength. Short bursts of high speed wind are termed gusts, strong winds of intermediate duration are termed squalls. Long-duration winds have various names associated with their strength, such as breeze, gale, storm. The two main causes of large-scale atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet, within the tropics, thermal low circulations over terrain and high plateaus can drive monsoon circulations. In coastal areas the sea breeze/land breeze cycle can define local winds, in areas that have variable terrain, mountain, Wind powers the voyages of sailing ships across Earths oceans. Hot air balloons use the wind to take trips, and powered flight uses it to increase lift. Areas of wind caused by various weather phenomena can lead to dangerous situations for aircraft. When winds become strong, trees and man-made structures are damaged or destroyed, Winds can shape landforms, via a variety of aeolian processes such as the formation of fertile soils, such as loess, and by erosion. Wind also affects the spread of wildfires, Winds can disperse seeds from various plants, enabling the survival and dispersal of those plant species, as well as flying insect populations. When combined with temperatures, wind has a negative impact on livestock. Wind affects animals food stores, as well as their hunting, Wind is caused by differences in the atmospheric pressure. When a difference in atmospheric pressure exists, air moves from the higher to the pressure area. On a rotating planet, air will also be deflected by the Coriolis effect, globally, the two major driving factors of large-scale wind patterns are the differential heating between the equator and the poles and the rotation of the planet. Outside the tropics and aloft from frictional effects of the surface, near the Earths surface, friction causes the wind to be slower than it would be otherwise
10.
Lidar
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Lidar is a surveying method that measures distance to a target by illuminating that target with a laser light. The name lidar, sometimes considered an acronym of Light Detection And Ranging, was originally a portmanteau of light, the technology is also used for control and navigation for some autonomous cars. Lidar sometimes is called laser scanning and 3D scanning, with terrestrial, airborne and its first applications came in meteorology, where the National Center for Atmospheric Research used it to measure clouds. The general public aware of the accuracy and usefulness of lidar systems in 1971 during the Apollo 15 mission. Although some sources treat the word lidar as an acronym, the term originated as a portmanteau of light, the first published mention of lidar, in 1963, makes this clear, Eventually the laser may provide an extremely sensitive detector of particular wavelengths from distant objects. Meanwhile, it is being used to study the moon by lidar, the Oxford English Dictionary supports this etymology. Currently no consensus exists on capitalization, reflecting uncertainty about whether or not lidar is an acronym, various publications refer to lidar as LIDAR, LiDAR, LIDaR, or Lidar. Lidar uses ultraviolet, visible, or near infrared light to image objects and it can target a wide range of materials, including non-metallic objects, rocks, rain, chemical compounds, aerosols, clouds and even single molecules. A narrow laser-beam can map physical features with high resolutions, for example. Lidar has been used extensively for research and meteorology. Lidar instruments fitted to aircraft and satellites carry out surveying and mapping – a recent example being the U. S. Geological Survey Experimental Advanced Airborne Research Lidar, NASA has identified lidar as a key technology for enabling autonomous precision safe landing of future robotic and crewed lunar-landing vehicles. Wavelengths vary to suit the target, from about 10 micrometers to the UV, typically light is reflected via backscattering, as opposed to pure reflection one might find with a mirror. Different types of scattering are used for different lidar applications, most commonly Rayleigh scattering, Mie scattering, Raman scattering, based on different kinds of backscattering, the lidar can be accordingly called Rayleigh Lidar, Mie Lidar, Raman Lidar, Na/Fe/K Fluorescence Lidar, and so on. Suitable combinations of wavelengths can allow for remote mapping of atmospheric contents by identifying wavelength-dependent changes in the intensity of the returned signal, in general there are two kinds of lidar detection schemes, incoherent or direct energy detection and coherent detection. In both coherent and incoherent lidar, there are two types of models, micropulse lidar systems and high energy systems. Micropulse systems utilizing intermittent bursts of energy have developed as a result of the amount of computer power available combined with advances in laser technology. They use considerably less energy in the laser, typically on the order of one microjoule, there are several major components to a lidar system, Laser — 600–1000 nm lasers are most common for non-scientific applications. They are inexpensive, but since they can be focused and easily absorbed by the eye, eye-safety is often a requirement for most applications
11.
Ultraviolet
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Ultraviolet is an electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation constitutes about 10% of the light output of the Sun. It is also produced by electric arcs and specialized lights, such as lamps, tanning lamps. Consequently, the effects of UV are greater than simple heating effects. Suntan, freckling and sunburn are familiar effects of over-exposure, along with risk of skin cancer. Living things on dry land would be damaged by ultraviolet radiation from the Sun if most of it were not filtered out by the Earths atmosphere. More-energetic, shorter-wavelength extreme UV below 121 nm ionizes air so strongly that it is absorbed before it reaches the ground, Ultraviolet is also responsible for the formation of bone-strengthening vitamin D in most land vertebrates, including humans. The UV spectrum thus has both beneficial and harmful to human health. Ultraviolet rays are invisible to most humans, the lens in a human eye ordinarily filters out UVB frequencies or higher, and humans lack color receptor adaptations for ultraviolet rays. Under some conditions, children and young adults can see ultraviolet down to wavelengths of about 310 nm, near-UV radiation is visible to some insects, mammals, and birds. Small birds have a fourth color receptor for ultraviolet rays, this gives birds true UV vision, reindeer use near-UV radiation to see polar bears, who are poorly visible in regular light because they blend in with the snow. UV also allows mammals to see urine trails, which is helpful for animals to find food in the wild. The males and females of some species look identical to the human eye. Ultraviolet means beyond violet, violet being the color of the highest frequencies of visible light, Ultraviolet has a higher frequency than violet light. He called them oxidizing rays to emphasize chemical reactivity and to them from heat rays. The terms chemical and heat rays were eventually dropped in favour of ultraviolet and infrared radiation, in 1878 the effect of short-wavelength light on sterilizing bacteria was discovered. By 1903 it was known the most effective wavelengths were around 250 nm, in 1960, the effect of ultraviolet radiation on DNA was established. The discovery of the ultraviolet radiation below 200 nm, named vacuum ultraviolet because it is absorbed by air, was made in 1893 by the German physicist Victor Schumann
12.
NASA
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President Dwight D. Eisenhower established NASA in 1958 with a distinctly civilian orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29,1958, disestablishing NASAs predecessor, the new agency became operational on October 1,1958. Since that time, most US space exploration efforts have led by NASA, including the Apollo Moon landing missions, the Skylab space station. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle, the agency is also responsible for the Launch Services Program which provides oversight of launch operations and countdown management for unmanned NASA launches. NASA shares data with various national and international such as from the Greenhouse Gases Observing Satellite. Since 2011, NASA has been criticized for low cost efficiency, from 1946, the National Advisory Committee for Aeronautics had been experimenting with rocket planes such as the supersonic Bell X-1. In the early 1950s, there was challenge to launch a satellite for the International Geophysical Year. An effort for this was the American Project Vanguard, after the Soviet launch of the worlds first artificial satellite on October 4,1957, the attention of the United States turned toward its own fledgling space efforts. This led to an agreement that a new federal agency based on NACA was needed to conduct all non-military activity in space. The Advanced Research Projects Agency was created in February 1958 to develop technology for military application. On July 29,1958, Eisenhower signed the National Aeronautics and Space Act, a NASA seal was approved by President Eisenhower in 1959. Elements of the Army Ballistic Missile Agency and the United States Naval Research Laboratory were incorporated into NASA, earlier research efforts within the US Air Force and many of ARPAs early space programs were also transferred to NASA. In December 1958, NASA gained control of the Jet Propulsion Laboratory, NASA has conducted many manned and unmanned spaceflight programs throughout its history. Some missions include both manned and unmanned aspects, such as the Galileo probe, which was deployed by astronauts in Earth orbit before being sent unmanned to Jupiter, the experimental rocket-powered aircraft programs started by NACA were extended by NASA as support for manned spaceflight. This was followed by a space capsule program, and in turn by a two-man capsule program. This goal was met in 1969 by the Apollo program, however, reduction of the perceived threat and changing political priorities almost immediately caused the termination of most of these plans. NASA turned its attention to an Apollo-derived temporary space laboratory, to date, NASA has launched a total of 166 manned space missions on rockets, and thirteen X-15 rocket flights above the USAF definition of spaceflight altitude,260,000 feet. The X-15 was an NACA experimental rocket-powered hypersonic research aircraft, developed in conjunction with the US Air Force, the design featured a slender fuselage with fairings along the side containing fuel and early computerized control systems
