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Sounding Rocket
A sounding rocket or rocketsonde, sometimes called a research rocket or a suborbital rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The rockets are used to launch instruments from 48 to 145 km (30 to 90 miles) above the surface of the Earth, the altitude generally between weather balloons and satellites; the maximum altitude for balloons is about 40 km (25 miles) and the minimum for satellites is approximately 121 km (75 miles). Certain sounding rockets have an apogee between 1,000 and 1,500 km (620 and 930 miles), such as the Black Brant X and XII, which is the maximum apogee of their class. Sounding rockets often use military surplus rocket motors. NASA routinely flies the Terrier Mk 70 boosted Improved Orion, lifting 270–450-kg (600–1,000-pound) payloads into the exoatmospheric region between 97 and 201 km (60 and 125 miles). Etymology The origin of the term ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Brant
The brant or brent goose (''Branta bernicla'') is a small goose of the genus '' Branta''. There are three subspecies, all of which winter along temperate-zone sea-coasts and breed on the high-Arctic tundra. The Brent oilfield was named after the species. Description The brant is a small goose with a short, stubby bill. It measures long, across the wings and weighs . The under-tail is pure white, and the tail black and very short (the shortest of any goose). The species is divided into three subspecies: * Dark-bellied brant goose ''B. b. bernicla'' (Linnaeus, 1758) * Pale-bellied brant goose ''B. b. hrota'' ( Müller, 1776) (also known as light-bellied brent goose in Europe, and Atlantic brant in North America) * Black brant goose ''B. b. nigricans'' (Lawrence, 1846) (sometimes also known as the Pacific brant in North America) Some DNA evidence suggests that these forms are genetically distinct; while a split into three separate species has been proposed, it is not wid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freefall
In Newtonian physics, free fall is any motion of a body where gravity is the only force acting upon it. In the context of general relativity, where gravitation is reduced to a space-time curvature, a body in free fall has no force acting on it. An object in the technical sense of the term "free fall" may not necessarily be falling down in the usual sense of the term. An object moving upwards might not normally be considered to be falling, but if it is subject to only the force of gravity, it is said to be in free fall. The Moon is thus in free fall around the Earth, though its orbital speed keeps it in very far orbit from the Earth's surface. In a roughly uniform gravitational field gravity acts on each part of a body approximately equally. When there are no other forces, such as the normal force exerted between a body (e.g. an astronaut in orbit) and its surrounding objects, it will result in the sensation of weightlessness, a condition that also occurs when the gravitation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measured with a thermometer. Thermometers are calibrated in various temperature scales that historically have relied on various reference points and thermometric substances for definition. The most common scales are the Celsius scale with the unit symbol °C (formerly called ''centigrade''), the Fahrenheit scale (°F), and the Kelvin scale (K), the latter being used predominantly for scientific purposes. The kelvin is one of the seven base units in the International System of Units (SI). Absolute zero, i.e., zero kelvin or −273.15 °C, is the lowest point in the thermodynamic temperature scale. Experimentally, it can be approached very closely but not actually reached, as recognized in the third law of thermodynamics. It would be impossible to extract energy as heat from a body at that temperature. Temperature is important in all fields of natur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiosonde
A radiosonde is a battery-powered telemetry instrument carried into the atmosphere usually by a weather balloon that measures various atmospheric parameters and transmits them by radio to a ground receiver. Modern radiosondes measure or calculate the following variables: altitude, pressure, temperature, relative humidity, wind (both wind speed and wind direction), cosmic ray readings at high altitude and geographical position (latitude/longitude). Radiosondes measuring ozone concentration are known as ozonesondes. Radiosondes may operate at a radio frequency of 403 MHz or 1680 MHz. A radiosonde whose position is tracked as it ascends to give wind speed and direction information is called a rawinsonde ("radar wind -sonde"). Most radiosondes have radar reflectors and are technically rawinsondes. A radiosonde that is dropped from an airplane and falls, rather than being carried by a balloon is called a dropsonde. Radiosondes are an essential source of meteorological data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocket
A rocket (from it, rocchetto, , bobbin/spool) is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely from propellant carried within the vehicle; therefore a rocket can fly in the vacuum of space. Rockets work more efficiently in a vacuum and incur a loss of thrust due to the opposing pressure of the atmosphere. Multistage rockets are capable of attaining escape velocity from Earth and therefore can achieve unlimited maximum altitude. Compared with airbreathing engines, rockets are lightweight and powerful and capable of generating large accelerations. To control their flight, rockets rely on momentum, airfoils, auxiliary reaction engines, gimballed thrust, momentum wheels, deflection of the exhaust stream, propellant flow, spin, or gravity. Rockets for military and recreational uses date back to at least 13th-century China. Signific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmosphere
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere is the outer region of a star, which includes the layers above the opaque photosphere; stars of low temperature might have outer atmospheres containing compound molecules. The atmosphere of Earth is composed of nitrogen (78%), oxygen (21%), argon (0.9%), carbon dioxide (0.04%) and trace gases. Most organisms use oxygen for respiration; lightning and bacteria perform nitrogen fixation to produce ammonia that is used to make nucleotides and amino acids; plants, algae, and cyanobacteria use carbon dioxide for photosynthesis. The layered composition of the atmosphere minimises the harmful effects of sunlight, ultraviolet radiation, the solar wind, and cosmic rays to protect organisms from genetic damage. The current comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weather
Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloudy. On Earth, most weather phenomena occur in the lowest layer of the planet's atmosphere, the troposphere, just below the stratosphere. Weather refers to day-to-day temperature, precipitation, and other atmospheric conditions, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, "weather" is generally understood to mean the weather of Earth. Weather is driven by air pressure, temperature, and moisture differences between one place and another. These differences can occur due to the Sun's angle at any particular spot, which varies with latitude. The strong temperature contrast between polar and tropical air gives rise to the largest scale atmospheric circulations: the Hadley cell, the Ferrel cell, the polar cell, and the jet stream. Weather system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Research
Field research, field studies, or fieldwork is the collection of raw data outside a laboratory, library, or workplace setting. The approaches and methods used in field research vary across disciplines. For example, biologists who conduct field research may simply observe animals interacting with their environments, whereas social scientists conducting field research may interview or observe people in their natural environments to learn their languages, folklore, and social structures. Field research involves a range of well-defined, although variable, methods: informal interviews, direct observation, participation in the life of the group, collective discussions, analyses of personal documents produced within the group, self-analysis, results from activities undertaken off- or on-line, and life-histories. Although the method generally is characterized as qualitative research, it may (and often does) include quantitative dimensions. History Field research has a long history. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Spaceflight
An orbital spaceflight (or orbital flight) is a spaceflight in which a spacecraft is placed on a trajectory where it could remain in space for at least one orbit. To do this around the Earth, it must be on a free trajectory which has an altitude at perigee (altitude at closest approach) around ; this is the boundary of space as defined by NASA, the US Air Force and the FAA. To remain in orbit at this altitude requires an orbital speed of ~7.8 km/s. Orbital speed is slower for higher orbits, but attaining them requires greater delta-v. The Fédération Aéronautique Internationale has established the Kármán line at an altitude of as a working definition for the boundary between aeronautics and astronautics. This is used because at an altitude of about , as Theodore von Kármán calculated, a vehicle would have to travel faster than orbital velocity to derive sufficient aerodynamic lift from the atmosphere to support itself. Due to atmospheric drag, the lowest altitude ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead Time
A lead time is the latency between the initiation and completion of a process. For example, the lead time between the placement of an order and delivery of new cars by a given manufacturer might be between 2 weeks and 6 months, depending on various particularities. One business dictionary defines "manufacturing lead time" as the total time required to manufacture an item, including order preparation time, queue time, setup time, run time, move time, inspection time, and put-away time. For make-to-order products, it is the time between release of an order and the production and shipment that fulfill that order. For make-to-stock products, it is the time taken from the release of an order to production and receipt into finished goods inventory. Supply chain management A conventional definition of lead time in a supply chain management context is the time from the moment the customer places an order (the moment the supplier learns of the requirement) to the moment it is ready for de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parachute
A parachute is a device used to slow the motion of an object through an atmosphere by creating drag or, in a ram-air parachute, aerodynamic lift. A major application is to support people, for recreation or as a safety device for aviators, who can exit from an aircraft at height and descend safely to earth. A parachute is usually made of a light, strong fabric. Early parachutes were made of silk. The most common fabric today is nylon. A parachute's canopy is typically dome-shaped, but some are rectangles, inverted domes, and other shapes. A variety of loads are attached to parachutes, including people, food, equipment, space capsules, and bombs. History Middle Ages In 852, in Córdoba, Spain, the Moorish man Armen Firman attempted unsuccessfully to fly by jumping from a tower while wearing a large cloak. It was recorded that "there was enough air in the folds of his cloak to prevent great injury when he reached the ground." Early Renaissance The earliest evidence f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
