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Laser Communication In Space
Laser communication in space is the use of free-space optical communication in outer space. Communication may be fully in space (an inter-satellite laser link) or in a ground-to-satellite or satellite-to-ground application. The main advantage of using laser communications over Radio, radio waves is increased Bandwidth (computing), bandwidth, enabling the transfer of more data in less time. In outer space, the communication range of free-space optical communication is currently of the order of hundreds of thousands of kilometers,. Laser-based optical communication has been demonstrated between the Earth and Moon and it has the potential to bridge interplanetary distances of millions of kilometers, using optical telescopes as beam expanders. Demonstrations and tests Before 1990 On 20 January 1968, the television camera of the Surveyor 7 lunar lander successfully detected two Ion laser, argon lasers from Kitt Peak National Observatory in Arizona and Table Mountain Observato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two Solar-powered Satellites Communicating Optically In Space Via Lasers
2 (two) is a number, numeral (linguistics), numeral and numerical digit, digit. It is the natural number following 1 and preceding 3. It is the smallest and only even prime number. Because it forms the basis of a Dualistic cosmology, duality, it has Religion, religious and Spirituality, spiritual significance in many Culture, cultures. Evolution Arabic digit The digit used in the modern Western world to represent the number 2 traces its roots back to the Indic Brahmic script, where "2" was written as two horizontal lines. The modern Chinese written language, Chinese and Japanese writing system, Japanese languages (and Korean Hanja) still use this method. The Gupta script rotated the two lines 45 degrees, making them diagonal. The top line was sometimes also shortened and had its bottom end curve towards the center of the bottom line. In the Devanagari, Nagari script, the top line was written more like a curve connecting to the bottom line. In the Arabic Ghubār numerals, G ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data-rate Units
In telecommunications, data-transfer rate is the average number of bits (bitrate), characters or symbols (baudrate), or data blocks per unit time passing through a communication link in a data-transmission system. Common data rate units are multiples of bits per second (bit/s) and bytes per second (B/s). For example, the data rates of modern residential high-speed Internet connections are commonly expressed in megabits per second (Mbit/s). Standards for unit symbols and prefixes Unit symbol The ISQ symbols for the bit and byte are ''bit'' and ''B'', respectively. In the context of data-rate units, one byte consists of 8 bits, and is synonymous with the unit octet. The abbreviation bps is often used to mean bit/s, so that when a ''1 Mbps'' connection is advertised, it usually means that the maximum achievable bandwidth is 1 Mbit/s (one million bits per second), which is 0.125 MB/s (megabyte per second), or about 0.1192 MiB/s (mebibyte per second). The Institu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OICETS
The Optical Inter-orbit Communications Engineering Test Satellite (OICETS), also called ''Kirari'', was an experimental satellite launched by JAXA to demonstrate interorbital communication between satellites through optical (laser) means. OICETS was originally slated for a launch on the second J-I launcher. Due to problems with that launcher, the launch had to be put on hold. Using the H-IIA was out of question: it would have been overkill to use the H-IIA to send a satellite into low Earth orbit, and there was no budget for another H-IIA launch. Finally, in order to be able to perform the tests during the lifetime of the European Artemis satellite (since 2014, sold to Avanti Communications to exploit its Ka, S, and L-band payloads), OICETS was successfully launched on an SS-18-based Dnepr rocket. The satellite was decommissioned and its mission terminated on 24 September 2009 at 05:48 UTC. Achievements *On 9 December 2005, JAXA succeeded in establishing optical links betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neodymium Laser
Nd:YAG (neodymium-doped yttrium aluminum garnet; Nd:Y3Al5O12) is a crystal that is used as a lasing medium for solid-state lasers. The dopant, triply ionized neodymium, Nd(III), typically replaces a small fraction (1%) of the yttrium ions in the host crystal structure of the yttrium aluminum garnet (YAG), since the two ions are of similar size.Koechner §2.3, pp. 48–53. It is the neodymium ion which provides the lasing activity in the crystal, in the same fashion as red chromium ion in ruby lasers. Laser operation of Nd:YAG was first demonstrated by J.E. Geusic ''et al.'' at Bell Laboratories in 1964. Technology Nd: YAG lasers are optically pumped using a flashtube or laser diodes. These are one of the most common types of laser, and are used for many different applications. Nd:YAG lasers typically emit light with a wavelength of 1064 nm, in the infrared. However, there are also transitions near 946, 1120, 1320, and 1440 nm. Nd:YAG lasers operate in both pulsed and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MESSENGER
''MESSENGER'' was a NASA robotic space probe that orbited the planet Mercury between 2011 and 2015, studying Mercury's chemical composition, geology, and magnetic field. The name is a backronym for "Mercury Surface, Space Environment, Geochemistry, and Ranging", and a reference to the messenger god Mercury from Roman mythology. ''MESSENGER'' was launched aboard a Delta II rocket in August 2004. Its path involved a complex series of flybys – the spacecraft flew by Earth once, Venus twice, and Mercury itself three times, allowing it to decelerate relative to Mercury using minimal fuel. During its first flyby of Mercury in January 2008, ''MESSENGER'' became the second mission, after Mariner 10 in 1975, to reach Mercury. ''MESSENGER'' entered orbit around Mercury on March 18, 2011, becoming the first spacecraft to do so. It successfully completed its primary mission in 2012. Following two mission extensions, the spacecraft used the last of its maneuvering propellant to deo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Altimeter
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light which is ''coherent''. Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers and lidar (light detection and ranging). Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum. Alternatively, temporal coherence can be used to produce ultrashort pulses of light ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury (planet)
Mercury is the smallest planet in the Solar System and the closest to the Sun. Its orbit around the Sun takes 87.97 Earth days, the shortest of all the Sun's planets. It is named after the Roman god ' ( Mercury), god of commerce, messenger of the gods, and mediator between gods and mortals, corresponding to the Greek god Hermes (). Like Venus, Mercury orbits the Sun within Earth's orbit as an inferior planet, and its apparent distance from the Sun as viewed from Earth never exceeds 28°. This proximity to the Sun means the planet can only be seen near the western horizon after sunset or the eastern horizon before sunrise, usually in twilight. At this time, it may appear as a bright star-like object, but is more difficult to observe than Venus. From Earth, the planet telescopically displays the complete range of phases, similar to Venus and the Moon, which recurs over its synodic period of approximately 116 days. The synodic proximity of Mercury to Earth makes Mercury most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japanese Optical Intersatellite Communications Engineering Test Satellite
Japanese may refer to: * Something from or related to Japan, an island country in East Asia * Japanese language, spoken mainly in Japan * Japanese people, the ethnic group that identifies with Japan through ancestry or culture ** Japanese diaspora, Japanese emigrants and their descendants around the world * Japanese citizens, nationals of Japan under Japanese nationality law ** Foreign-born Japanese, naturalized citizens of Japan * Japanese writing system, consisting of kanji and kana * Japanese cuisine, the food and food culture of Japan See also * List of Japanese people * * Japonica (other) * Japonicum * Japonicus * Japanese studies Japanese studies (Japanese: ) or Japan studies (sometimes Japanology in Europe), is a sub-field of area studies or East Asian studies involved in social sciences and humanities research on Japan. It incorporates fields such as the study of Japanese ... {{disambiguation Language and nationality disambiguation pages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SPOT (satellite)
SPOT (french: Satellite Pour l’Observation de la Terre, lit. "Satellite for observation of Earth") is a commercial high-resolution optical Earth imaging satellite system operating from space. It is run by Spot Image, based in Toulouse, France. It was initiated by the CNES (''Centre national d'études spatiales'' – the French space agency) in the 1970s and was developed in association with the SSTC (Belgian scientific, technical and cultural services) and the Swedish National Space Board (SNSB). It has been designed to improve the knowledge and management of the Earth by exploring the Earth's resources, detecting and forecasting phenomena involving climatology and oceanography, and monitoring human activities and natural phenomena. The SPOT system includes a series of satellites and ground control resources for satellite control and programming, image production, and distribution. Earlier satellites were launched using the European Space Agency's Ariane 2, 3, and 4 rocket ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth Observation Satellite
An Earth observation satellite or Earth remote sensing satellite is a satellite used or designed for Earth observation (EO) from orbit, including spy satellites and similar ones intended for non-military uses such as environmental monitoring, meteorology, cartography and others. The most common type are Earth imaging satellites, that take satellite images, analogous to aerial photographs; some EO satellites may perform remote sensing without forming pictures, such as in GNSS radio occultation. The first occurrence of satellite remote sensing can be dated to the launch of the first artificial satellite, Sputnik 1, by the Soviet Union on October 4, 1957. Sputnik 1 sent back radio signals, which scientists used to study the ionosphere. The United States Army Ballistic Missile Agency launched the first American satellite, Explorer 1, for NASA’s Jet Propulsion Laboratory on January 31, 1958. The information sent back from its radiation detector led to the discovery of the Earth's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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