|
E-sail
An electric sail (also known as an electric solar wind sail or an E-sail) is a proposed form of spacecraft propulsion using the dynamic pressure of the solar wind as a source of thrust. It creates a "virtual" sail by using small wires to form an electric field that deflects solar wind protons and extracts their momentum. The idea was first conceptualised by Pekka Janhunen in 2006 at the Finnish Meteorological Institute. Principles of operation and design The electric sail consists of a number of thin, long and conducting tethers which are kept in a high positive potential by an onboard electron gun. The positively charged tethers deflect solar wind protons, thus extracting momentum from them. Simultaneously they attract electrons from the solar wind plasma, producing an electron current. The electron gun compensates for the arriving electric current. One way to deploy the tethers is to rotate the spacecraft, using centrifugal force to keep them stretched. By fine-tuning the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ESTCube-1
ESTCube-1 is the first Estonian satellite and first satellite in the world to attempt to use an electric solar wind sail (E-sail). It was launched on 7 May 2013 aboard Vega VV02 carrier rocket and successfully deployed into orbit. The CubeSat standard for nanosatellites was followed during the engineering of ESTCube-1, resulting in a 10×10×11.35 cm cube, with a volume of 1 liter and a mass of 1.048 kg. The mission ended officially on 17 February 2015 and it was said that during this time it resulted in 29 bachelor's and 19 master's dissertations, 5 doctoral theses and 4 start-ups. The deployment of the E-sail tether was unsuccessful, and thus no measurements were taken of the E-sail or of the plasma braking deployment system. The last signal from ESTCube-1 was received on 19 May 2015. Scientific purpose Developed as part of the Estonian Student Satellite Program, ESTCube-1 was an educational project in which university and high school students participated. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spacecraft Propulsion
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. In-space propulsion exclusively deals with propulsion systems used in the vacuum of space and should not be confused with space launch or atmospheric entry. Several methods of pragmatic spacecraft propulsion have been developed each having its own drawbacks and advantages. Most satellites have simple reliable chemical thrusters (often monopropellant rockets) or resistojet rockets for orbital station-keeping and some use momentum wheels for attitude control. Soviet bloc satellites have used electric propulsion for decades, and newer Western geo-orbiting spacecraft are starting to use them for north–south station-keeping and orbit raising. Interplanetary vehicles mostly use chemical rockets as well, although a few have used ion thrusters and Hall-effect thrusters (two different types of electric propulsion) to great success. Hypothetical in-space propulsion technologies descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Sail
Solar sails (also known as light sails and photon sails) are a method of spacecraft propulsion using radiation pressure exerted by sunlight on large mirrors. A number of spaceflight missions to test solar propulsion and navigation have been proposed since the 1980s. The first spacecraft to make use of the technology was IKAROS, launched in 2010. A useful analogy to solar sailing may be a sailing boat; the light exerting a force on the mirrors is akin to a sail being blown by the wind. High-energy laser beams could be used as an alternative light source to exert much greater force than would be possible using sunlight, a concept known as beam sailing. Solar sail craft offer the possibility of low-cost operations combined with long operating lifetimes. Since they have few moving parts and use no propellant, they can potentially be used numerous times for delivery of payloads. Solar sails use a phenomenon that has a proven, measured effect on astrodynamics. Solar pressure aff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pekka Janhunen
Pekka Janhunen is a space physicist, astrobiologist, and inventor. Janhunen, Ph.D., is a Research Manager at Finnish Meteorological Institute's Space and Earth Observation Centre, and a visiting professor at University of Tartu, Estonia. He is also senior technical advisor at Aurora Propulsion Technologies, a startup company, operating in space sector. He studied theoretical physics at the University of Helsinki, and made his PhD on space plasma physics simulations in 1994. He has also published a theory on the origin of multicellular life. He is best known for his Electric Solar Wind Sail invention. Research The Electric Sail The Electric Sail could enable travelling at speeds up to 100 km/s in space without any fuel consumption. With no major problems in any of the technical fields thus far, the planning of the first test mission has started, according to an article by Sciencedaily. In the same article, Sciencedaily wrote that "the electric solar wind sail developed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finnish Meteorological Institute
The Finnish Meteorological Institute (FMI; fi, Ilmatieteen laitos; sv, Meteorologiska institutet) is the government agency responsible for gathering and reporting weather data and forecasts in Finland. It is a part of the Ministry of Transport and Communications but it operates semi-autonomously. The Institute is an impartial research and service organisation with expertise covering a wide range of atmospheric science activities other than gathering and reporting weather data and forecasts. The headquarters of the Institute is in Kumpula Campus, Helsinki, Finland. Services FMI provides weather forecasts for aviation, traffic, shipping and media as well as private citizens via internet and mobile devices. It also has air quality services. For sea areas, it provides information about ice cover, sea level changes and waves. In 2013 FMI made openly available data sets such as weather, sea and climate observation data, time series and model data. The open data is targeted to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultrasonic Welding
Ultrasonic welding is an industrial process whereby high-frequency ultrasonic acoustic vibrations are locally applied to work pieces being held together under pressure to create a solid-state weld. It is commonly used for plastics and metals, and especially for joining dissimilar materials. In ultrasonic welding, there are no connective bolts, nails, soldering materials, or adhesives necessary to bind the materials together. When used to join metals, the temperature stays well below the melting point of the involved materials, preventing any unwanted properties which may arise from high temperature exposure of the metal. History Practical application of ultrasonic welding for rigid plastics was completed in the 1960s. At this point only hard plastics could be welded. The patent for the ultrasonic method for welding rigid thermoplastic parts was awarded to Robert Soloff and Seymour Linsley in 1965. Soloff, the founder of Sonics & Materials Inc., was a lab manager at Branson Instr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Academy Of Finland
The Academy of Finland ( fi, Suomen Akatemia, sv, Finlands Akademi) is a governmental funding body for scientific research in Finland. It is based in Helsinki. Yearly, the Academy administers over 260 million euros to Finnish research activities. Over 5000 researchers are working on projects supported by the academy. The Academy functions as a funding body only and is not a school. However, personnel funded by the Academy can use the title referring to it, e.g. professors will be called ''akatemiaprofessori''. Academy Professor funding has a term of 5 years. The Academy of Finland should not be confused with the Finnish arts and science school learned societies, The Finnish Academy of Science and Letters (''Suomalainen tiedeakatemia'') and The Finnish Society of Science and Letters (''Finska Vetenskaps-Societeten'') which are the two Finnish national honorary academies, for Finnish and Swedish-speaking scientists and scholars, respectively. For engineers, the two language-based h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Union
The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been described as a ''sui generis'' political entity (without precedent or comparison) combining the characteristics of both a federation and a confederation. Containing 5.8per cent of the world population in 2020, the EU generated a nominal gross domestic product (GDP) of around trillion in 2021, constituting approximately 18per cent of global nominal GDP. Additionally, all EU states but Bulgaria have a very high Human Development Index according to the United Nations Development Programme. Its cornerstone, the Customs Union, paved the way to establishing an internal single market based on standardised legal framework and legislation that applies in all member states in those matters, and only those matters, where the states have agree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estonia
Estonia, formally the Republic of Estonia, is a country by the Baltic Sea in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the sea across from Sweden, to the south by Latvia, and to the east by Lake Peipus and Russia. The territory of Estonia consists of the mainland, the larger islands of Saaremaa and Hiiumaa, and over 2,200 other islands and islets on the eastern coast of the Baltic Sea, covering a total area of . The capital city Tallinn and Tartu are the two largest urban areas of the country. The Estonian language is the autochthonous and the official language of Estonia; it is the first language of the majority of its population, as well as the world's second most spoken Finnic language. The land of what is now modern Estonia has been inhabited by '' Homo sapiens'' since at least 9,000 BC. The medieval indigenous population of Estonia was one of the last "pagan" civilisations in Europe to adop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliopause Electrostatic Rapid Transit System - HERTS
Heliopause may refer to: * Heliopause (astronomy), the theoretical boundary where the Sun's solar wind is stopped by the interstellar medium. * Heliopause (band) Heliopause are a U.K. band based in Belfast and Brighton Brighton () is a seaside resort and one of the two main areas of the City of Brighton and Hove in the county of East Sussex, England. It is located south of London. Archaeological ..., a U.K. band * ''Heliopause'' (album), a 2011 album by The Resonance Association {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Unit
The astronomical unit (symbol: au, or or AU) is a unit of length, roughly the distance from Earth to the Sun and approximately equal to or 8.3 light-minutes. The actual distance from Earth to the Sun varies by about 3% as Earth orbits the Sun, from a maximum ( aphelion) to a minimum ( perihelion) and back again once each year. The astronomical unit was originally conceived as the average of Earth's aphelion and perihelion; however, since 2012 it has been defined as exactly (see below for several conversions). The astronomical unit is used primarily for measuring distances within the Solar System or around other stars. It is also a fundamental component in the definition of another unit of astronomical length, the parsec. History of symbol usage A variety of unit symbols and abbreviations have been in use for the astronomical unit. In a 1976 resolution, the International Astronomical Union (IAU) had used the symbol ''A'' to denote a length equal to the ast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrometeoroid
A micrometeoroid is a tiny meteoroid: a small particle of rock in space, usually weighing less than a gram. A micrometeorite is such a particle that survives passage through Earth's atmosphere and reaches Earth's surface. The term "micrometeoroid" was officially deprecated by the IAU in 2017, as redundant to meteoroid. Origins and orbits Micrometeoroids are very small pieces of rock or metal broken off from larger chunks of rock and debris often dating back to the birth of the Solar System. Micrometeoroids are extremely common in space. Tiny particles are a major contributor to space weathering processes. When they hit the surface of the Moon, or any airless body ( Mercury, the asteroids, etc.), the resulting melting and vaporization causes darkening and other optical changes in the regolith. Micrometeoroids have less stable orbits than meteoroids, due to their greater surface area to mass ratio. Micrometeoroids that fall to Earth can provide information on millimeter sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
