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Mars Surveyor '98
Mars Surveyor '98 was a mission in NASA's Mars Exploration Program that launched the ''Mars Climate Orbiter'' and the Mars Polar Lander to the planet Mars. The mission was to study the Martian weather, Climate of Mars, climate, Water on Mars, water and carbon dioxide (CO2) budget, to understand the reservoirs, behavior, and atmospheric role of volatiles and to search for evidence of long-term and episodic climate changes. The Mars Polar Lander also carried two surface-penetrator probes for the New Millennium Program's Deep Space 2 mission. Both spacecraft were launched in 1998 and both were lost. Spacecraft Orbiter The orbiter was lost due to a miscalculation in trajectory caused by an unintended and undetected mismatch between SI, metric and English units of measurement. The use of metric units as well as the data formats to employ were specified in a navigation software interface specification (SIS) published by JPL in 1996. Despite this, the flight operations team at Lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars Climate Orbiter 2
Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmospheric pressure is a few thousandths of Earth's, atmospheric temperature ranges from and cosmic radiation is high. Mars retains some water, in the ground as well as thinly in the atmosphere, forming cirrus clouds, frost, larger polar regions of permafrost and ice caps (with seasonal snow), but no liquid surface water. Its surface gravity is roughly a third of Earth's or double that of the Moon. It is half as wide as Earth or twice the Moon, with a diameter of , and has a surface area the size of all the dry land of Earth. Fine dust is prevalent across the surface and the atmosphere, being picked up and spread at the low Martian gravity even by the weak wind of the tenuous atmosphere. The terrain of Mars roughly follows a north-south divid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Space 2
Deep Space 2 was a NASA space probe, part of the New Millennium Program. It included two highly advanced miniature space probes that were sent to Mars aboard the Mars Polar Lander in January 1999. The probes were named "Scott" and "Amundsen", in honor of Robert Falcon Scott and Roald Amundsen, the first explorers to reach the Earth's South Pole. Intended to be the first spacecraft to penetrate below the surface of another planet, after entering the Mars atmosphere DS2 was to detach from the Mars Polar Lander mother ship and plummet to the surface using only an aeroshell impactor, with no parachute. The mission was declared a failure on March 13, 2000, after all attempts to reestablish communications following the descent went unanswered. The Deep Space 2 development costs were US$28 million. Overview thumbnail, Deep Space 2 project manager Sarah Gavit with the engineering hardware of the probe Deep Space 2, also known as "Mars Microprobe," was the second spacecraft develope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nozomi (spacecraft)
was a Japanese Mars orbiter that failed to reach Mars due to electrical failure. It was constructed by the Institute of Space and Astronautical Science, University of Tokyo and launched on July 4, 1998, at 03:12 JST (July 3, 1998, at 18:12 UTC) with an on-orbit dry mass of 258 kg and 282 kg of propellant. The Nozomi mission was terminated on December 31, 2003. ''Nozomi'' was designed to study the upper Martian atmosphere and its interaction with the solar wind and to develop technologies for use in future planetary missions. Specifically, instruments on the spacecraft were to measure the structure, composition and dynamics of the ionosphere, aeronomy effects of the solar wind, the escape of atmospheric constituents, the intrinsic magnetic field, the penetration of the solar-wind magnetic field, the structure of the magnetosphere, and dust in the upper atmosphere and in orbit around Mars. The mission would have also returned images of Mars's surface. Mission profile La ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Missions To Mars
This is a list of spacecraft missions (including unsuccessful ones) to the planet Mars, such as orbiters, landers, and rovers. Missions ;Mission Type Legend: Landing locations In 1999, Mars Climate Orbiter accidentally entered Mars' atmosphere and either burnt up or left Mars' orbit on an unknown trajectory. There are a number of derelict spacecraft orbiting Mars whose location is not known precisely. There is a proposal to use the Optical Navigation Camera on the '' Mars Reconnaissance Orbiter'' to search for small moons, dust rings and old orbiters. As of 2016, there were believed to be eight derelict spacecraft in orbit around Mars (barring unforeseen event). The Viking 1 orbiter was not expected to decay until at least 2019. Mariner 9, which entered Mars orbit in 1971, was expected to remain in orbit until approximately 2022, when it was projected to enter the Martian atmosphere and either burn up, or crash into the planet's surface. Timeline Missions to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Instability
In dynamical systems instability means that some of the outputs or internal states increase with time, without bounds. Not all systems that are not stable are unstable; systems can also be marginally stable or exhibit limit cycle behavior. In structural engineering, a structural beam or column can become unstable when excessive compressive load is applied. Beyond a certain threshold, structural deflections magnify stresses, which in turn increases deflections. This can take the form of buckling or crippling. The general field of study is called structural stability. Atmospheric instability is a major component of all weather systems on Earth. Instability in control systems In the theory of dynamical systems, a state variable in a system is said to be unstable if it evolves without bounds. A system itself is said to be unstable if at least one of its state variables is unstable. In continuous time control theory, a system is unstable if any of the roots of its charac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Misfire
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Misfire may refer to: * Misfire (Transformers), the Transformers character * ''Misfire'' (film), a 2014 American action film * "Misfire" (That '70s Show), an episode from ''That '70s Show'' * An engine misfire, see engine knocking * A song on Queen's album ''Sheer Heart Attack'' * A malfunctioned cartridge that fails to discharge at all ( dud), doesn't discharge promptly (hang fire), or only partially discharges (squib load) when being shot from a firearm. * A muzzleloader that does not fire when the trigger is squeezed. See also * Firearm malfunction A firearm malfunction is the failure of a firearm to operate as intended for causes other than user error. Malfunctions range from temporary and relatively safe situations, such as a casing (ammunition), casing that did not eject, to potentially d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thrust
Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that system. The force applied on a surface in a direction perpendicular or normal to the surface is also called thrust. Force, and thus thrust, is measured using the International System of Units (SI) in newtons (symbol: N), and represents the amount needed to accelerate 1 kilogram of mass at the rate of 1 meter per second per second. In mechanical engineering, force orthogonal to the main load (such as in parallel helical gears) is referred to as static thrust. Examples A fixed-wing aircraft propulsion system generates forward thrust when air is pushed in the direction opposite to flight. This can be done by different means such as the spinning blades of a propeller, the propelling jet of a jet engine, or by ejecting hot gases f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rocket Nozzle
A rocket engine nozzle is a propelling nozzle (usually of the de Laval type) used in a rocket engine to expand and accelerate combustion products to high supersonic velocities. Simply: propellants pressurized by either pumps or high pressure ullage gas to anywhere between two and several hundred atmospheres are injected into a combustion chamber to burn, and the combustion chamber leads into a nozzle which converts the energy contained in high pressure, high temperature combustion products into kinetic energy by accelerating the gas to high velocity and near-ambient pressure. History Simple bell-shaped nozzles were developed in the 1500s. The de Laval nozzle was originally developed in the 19th century by Gustaf de Laval for use in steam turbines. It was first used in an early rocket engine developed by Robert Goddard, one of the fathers of modern rocketry. It has since been used in almost all rocket engines, including Walter Thiel's implementation, which made possible Ger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrazine
Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydrazine hydrate (). Hydrazine is mainly used as a foaming agent in preparing Polymeric foam, polymer foams, but applications also include its uses as a precursor (chemistry), precursor to pharmaceuticals and agrochemicals, as well as a long-term storable propellant for in-outer space, space spacecraft propulsion. Additionally, hydrazine is used in various rocket propellant, rocket fuels and to prepare the gas precursors used in airbags. Hydrazine is used within both nuclear and conventional electrical power plant steam cycles as an oxygen scavenger to control concentrations of dissolved oxygen in an effort to reduce corrosion. , approximately 120,000 tons of hydrazine hydrate (corresponding to a 64% solution of hydrazine in water by weight) we ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalysis
Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. The rate increase occurs because the catalyst allows the reaction to occur by an alternative mechanism which may be much faster than the noncatalyzed mechanism. However the noncatalyzed mechanism does remain possible, so that the total rate (catalyzed plus noncatalyzed) can only increase in the presence of the catalyst and never decrease. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pound-force
The pound of force or pound-force (symbol: lbf, sometimes lbf,) is a unit of force used in some systems of measurement, including English Engineering units and the foot–pound–second system. Pound-force should not be confused with pound-mass (lb), often simply called "pound", which is a unit of mass; nor should these be confused with foot-pound (ft⋅lbf), a unit of energy, or pound-foot (lbf⋅ft), a unit of torque. Definitions The pound-force is equal to the gravitational force exerted on a mass of one avoirdupois pound on the surface of Earth. Since the 18th century, the unit has been used in low-precision measurements, for which small changes in Earth's gravity (which varies from equator to pole by up to half a percent) can safely be neglected. The 20th century, however, brought the need for a more precise definition, requiring a standardized value for acceleration due to gravity. Product of avoirdupois pound and standard gravity The pound-force is the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
English Units
English units were the units of measurement used in England up to 1826 (when they were replaced by Imperial units), which evolved as a combination of the Anglo-Saxons, Anglo-Saxon and Ancient Roman units of measurement, Roman systems of units. Various standards have applied to English units at different times, in different places, and for different applications. Use of the term "English units" can be ambiguous, as, in addition to the meaning used in this article, it is sometimes used to refer to the units of the descendant Imperial system as well to those of the descendant system of United States customary units. The two main sets of English units were the Winchester measure, Winchester Units, used from 1495 to 1587, as affirmed by Henry VII of England, King Henry VII, and the Exchequer Standards, in use from 1588 to 1825, as defined by Queen Elizabeth I. In England (and the British Empire), English units were replaced by Imperial units in 1824 (effective as of 1 January 1826) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
