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Sky Anchor
A sky anchor is a system of two balloons in tandem, with a "zero-pressure" lifting gas balloon tethered to a superpressure balloon "anchor". The gas balloon is filled with a lifting gas and provides the buoyancy, while the superpressure balloon is filled with air, and pressurized to provide the desired ballast weight. In a passive sky anchor, the superpressure balloon is sealed, while in an active system, its pressure can be varied. Both versions have been tested in flight, but have had frequent failures with only occasional successful outcomes. The tandem arrangement makes launching difficult, and this complexity can lead to mission failure. The tandem balloon system is intended to increase the flight time of the zero-pressure balloon by damping the diurnal altitude variations caused by solar heating of the lifting gas and its subsequent expansion. As the balloons descend, the superpressure balloon's constant volume displaces a larger mass of the denser air, and becomes more buoy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Balloon
A gas balloon is a balloon that rises and floats in the air because it is filled with a gas lighter than air (such as helium or hydrogen). When not in flight, it is tethered to prevent it from flying away and is sealed at the bottom to prevent the escape of gas. A gas balloon may also be called a '' Charlière'' for its inventor, the Frenchman Jacques Charles. Today, familiar gas balloons include large blimps and small latex party balloons. For nearly 200 years, well into the 20th century, manned balloon flight utilized gas balloons before hot-air balloons became dominant. Without power, heat or fuel, untethered flights of gas balloons depended on the skill of the pilot. Gas balloons have greater lift for a given volume, so they do not need to be so large, and they can stay up for much longer than hot air balloons. History The first gas balloon made its flight in August 1783. Designed by professor Jacques Charles and Les Frères Robert, it carried no passengers or cargo. On ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superpressure Balloon
A superpressure balloon (SPB) is a style of aerostatic balloon where the volume of the balloon (aircraft), balloon is kept relatively constant in the face of changes in ambient pressure outside the balloon, and the temperature of the contained lifting gas. This allows the balloon to keep a stable altitude for long periods. This is in contrast with much more common variable-volume balloons, which are either only partially filled with lifting gas, or made with more elastic materials. Also referred to as pumpkin or ultra long distance balloons (ULDB) balloons, the sealed balloon envelopes have a pumpkin shape at flight altitude. Operation In a variable-volume balloon, the volume of the lifting gas changes due to heating and cooling in the Diurnal temperature variation, diurnal cycle. The cycle is magnified by a greenhouse effect inside the balloon, while the surrounding atmospheric gas is subject to a much more limited cyclical temperature change. As the lift gas heats and expands ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lifting Gas
A lifting gas or lighter-than-air gas is a gas that has a density lower than normal atmospheric gases and rises above them as a result, making it useful in lifting lighter-than-air aircraft. Only certain lighter-than-air gases are suitable as lifting gases. Dry air has a density of about 1.29 g/L (gram per liter) at standard conditions for temperature and pressure (STP) and an average molecular mass of 28.97 g/mol, and so lighter-than-air gases have a density lower than this. Gases used for lifting Hot air Heated atmospheric air is frequently used in recreational ballooning. According to the ideal gas law, an amount of gas (and also a mixture of gases such as air) expands as it is heated. As a result, a certain volume of gas has a lower density as its temperature increases. The temperature of the hot air in the envelope will vary depending upon the ambient temperature, but the maximum continuous operating temperature for most balloons is . Hydrogen Hydrogen, being the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buoyancy
Buoyancy (), or upthrust, is the force exerted by a fluid opposing the weight of a partially or fully immersed object (which may be also be a parcel of fluid). In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus, the pressure at the bottom of a column of fluid is greater than at the top of the column. Similarly, the pressure at the bottom of an object submerged in a fluid is greater than at the top of the object. The pressure difference results in a net upward force on the object. The magnitude of the force is proportional to the pressure difference, and (as explained by Archimedes' principle) is equivalent to the weight of the fluid that would otherwise occupy the submerged volume of the object, i.e. the Displacement (fluid), displaced fluid. For this reason, an object with average density greater than the surrounding fluid tends to sink because its weight is greater than the weight of the fluid it displaces. If the objec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diurnal Temperature Variation
In meteorology, diurnal temperature variation is the variation between a high air temperature and a low temperature that occurs during the same day. Temperature lag Temperature lag, also known as thermal inertia, is an important factor in diurnal temperature variation. Peak daily temperature generally occurs ''after'' noon, as air keeps absorbing net heat for a period of time from morning through noon and some time thereafter. Similarly, minimum daily temperature generally occurs substantially after midnight, indeed occurring during early morning in the hour around dawn, since heat is lost all night long. The analogous annual phenomenon is seasonal lag. As solar energy strikes the Earth's surface each morning, a shallow layer of air directly above the ground is heated by conduction. Heat exchange between this shallow layer of warm air and the cooler air above is very inefficient. On a warm summer's day, for example, air temperatures may vary by from just above the ground t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Texas A&M University
Texas A&M University (Texas A&M, A&M, TA&M, or TAMU) is a public university, public, Land-grant university, land-grant, research university in College Station, Texas, United States. It was founded in 1876 and became the flagship institution of the Texas A&M University System in 1948. Since 2021, Texas A&M has enrolled the List of United States university campuses by enrollment, largest student body in the United States. It is Carnegie Classification of Institutions of Higher Education, classified among "R1: Doctoral Universities – Very high research activity" and since 2001 a member of the Association of American Universities. The university was the first public higher education institution in Texas; it opened for classes on October 4, 1876, as the History of Texas A&M University, Agricultural and Mechanical College of Texas (A.M.C.) under the provisions of the 1862 Morrill Land-Grant Acts, Morrill Land-Grant Act. In the following decades, the college grew in size and scope, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Circumnavigation
Circumnavigation is the complete navigation around an entire island, continent, or astronomical object, astronomical body (e.g. a planet or natural satellite, moon). This article focuses on the circumnavigation of Earth. The first circumnavigation of the Earth was the Magellan's circumnavigation, Magellan Expedition, which sailed from Sanlucar de Barrameda, Spain in 1519 and returned in 1522, after crossing the Atlantic Ocean, Atlantic, Pacific Ocean, Pacific, and Indian Ocean, Indian oceans. Since the rise of commercial aviation in the late 20th century, circumnavigating Earth is straightforward, usually taking days instead of years. Today, the challenge of circumnavigating Earth has shifted towards human and technological endurance, speed, and List of circumnavigations#Miscellaneous, less conventional methods. Etymology The word ''circumnavigation'' is a noun formed from the verb ''circumnavigate'', from the past participle of the Latin verb ''circumnavigare'', from ''circum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Stream
Jet streams are fast flowing, narrow thermal wind, air currents in the Earth's Atmosphere of Earth, atmosphere. The main jet streams are located near the altitude of the tropopause and are westerly winds, flowing west to east around the globe. The northern hemisphere and the southern hemisphere each have a polar jet around their respective polar vortex at around above sea level and typically travelling at around although often considerably faster. Closer to the equator and somewhat higher and somewhat weaker is a subtropical jet. The northern polar jet flows over the middle to northern latitudes of North America, Europe, and Asia and their intervening oceans, while the southern hemisphere polar jet mostly circles Antarctica. Jet streams may start, stop, split into two or more parts, combine into one stream, or flow in various directions including opposite to the direction of the remainder of the jet. The El Niño–Southern Oscillation affects the location of the jet s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Institute Of Aeronautics And Astronautics
The American Institute of Aeronautics and Astronautics (AIAA) is a professional society for the field of aerospace engineering Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is s .... The AIAA is the U.S. representative on the International Astronautical Federation and the International Council of the Aeronautical Sciences. In 2015, it had more than 30,000 members among aerospace professionals worldwide (a majority are American or live in the United States). History The AIAA was founded in 1963 from the merger of two earlier societies: the American Rocket Society (ARS), founded in 1930 as the American Interplanetary Society (AIS), and the Institute of the Aerospace Sciences (IAS), founded in 1932 as the Institute of the Aeronautical Sciences. Paul Johnston was the first executive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Houston, Texas
Houston ( ) is the List of cities in Texas by population, most populous city in the U.S. state of Texas and in the Southern United States. Located in Southeast Texas near Galveston Bay and the Gulf of Mexico, it is the county seat, seat of Harris County, Texas, Harris County, as well as the principal city of the Greater Houston metropolitan area, the fifth-most populous metropolitan statistical area in the United States and the List of Texas metropolitan areas, second-most populous in Texas after Dallas–Fort Worth metroplex, Dallas–Fort Worth. With a population of 2,314,157 in 2023, Houston is the List of United States cities by population, fourth-most populous city in the United States after New York City, Los Angeles, and Chicago, and the List of North American cities by population, sixth-most populous city in North America. Houston is the southeast anchor of the greater megaregion known as the Texas Triangle. Comprising a land area of , Houston is the List of United S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
COSPAR
The Committee on Space Research (COSPAR) was established on October 3, 1958 by the International Council for Science, International Council for Scientific Unions (ICSU) and its first chair was Hildegard Korf Kallmann-Bijl. Among COSPAR's objectives are the promotion of scientific research in outer space, space on an international level, with emphasis on the free exchange of results, information, and opinions, and providing a forum, open to all scientists, for the discussion of problems that may affect space research. These objectives are achieved through the organization of symposia, publication, and other means. COSPAR has created a number of research programmes on different topics, a few in cooperation with other scientific Unions. The long-term project COSPAR international reference atmosphere started in 1960; since then it has produced several editions of the high-atmosphere code COSPAR international reference atmosphere, CIRA. The code "IRI" of the URSI-COSPAR working grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
