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26-511: Freestar is a name used more than once: FREESTAR , a science package, including MEIDEX, SOLSE and other experiments, carried on Space Shuttle Columbia during STS-107 . Ford Freestar , a car designed by Ford Motor Company . Freestar is an alcohol free beer made in the UK Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

52-461: A r 2 σ T s t a r 4 {\displaystyle 4\pi f\ d^{2}=4\pi R_{\rm {star}}^{2}\sigma T_{\rm {star}}^{4}} f = ( R s t a r 2 σ T s t a r 4 d 2 ) {\displaystyle f=\left({\frac {R_{\rm {star}}^{2}\sigma T_{\rm {star}}^{4}}{d^{2}}}\right)} Where f

78-425: A Seagate ST9385AG 2.5" hard drive with 400 MB storage capacity, was found and believed to be melted beyond recognition. In 2008, however, a data recovery specialist cleaned the hard drive's storage platters and rebuilt them into a new hard drive. They were able to recover 99% of the data, saving the experiment. The SOLCON instrument is designed to accurately measure the solar constant and identify variations in

104-670: A measurement that he made from Mont Blanc in France. In 1884, Samuel Pierpont Langley attempted to estimate the solar constant from Mount Whitney in California. By taking readings at different times of day, he tried to correct for effects due to atmospheric absorption. However, the final value he proposed, 2.903 kW/m , was much too large. Between 1902 and 1957, measurements by Charles Greeley Abbot and others at various high-altitude sites found values between 1.322 and 1.465 kW/m . Abbot showed that one of Langley's corrections

130-595: A year (from 1.412 kW/m in early January to 1.321 kW/m in early July) due to the Earth's varying distance from the Sun, and typically by much less than 0.1% from day to day. Thus, for the whole Earth (which has a cross section of 127,400,000 km ), the power is 1.730×10   W (or 173,000 terawatts ), plus or minus 3.5% (half the approximately 6.9% annual range). The solar constant does not remain constant over long periods of time (see Solar variation ), but over

156-500: A year the solar constant varies much less than the solar irradiance measured at the top of the atmosphere. This is because the solar constant is evaluated at a fixed distance of 1 Astronomical Unit (au) while the solar irradiance will be affected by the eccentricity of the Earth's orbit. Its distance to the Sun varies annually between 147.1·10 km at perihelion and 152.1·10  km at aphelion . In addition, several long term (tens to hundreds of millennia) cycles of subtle variation in

182-399: Is the irradiance of the star at the extrasolar planet at distance d. In 1838, Claude Pouillet made the first estimate of the solar constant. Using a very simple pyrheliometer he developed, he obtained a value of 1.228 kW/m , close to the current estimate. In 1875, Jules Violle resumed the work of Pouillet and offered a somewhat larger estimate of 1.7 kW/m based, in part, on

208-459: The 11-year solar cycle when the number of sunspots is minimal) and approximately 0.1% greater (roughly 1.362 kW/m ) at solar maximum . The solar "constant" is not a physical constant in the modern CODATA scientific sense; that is, it is not like the Planck constant or the speed of light which are absolutely constant in physics. The solar constant is an average of a varying value. In

234-423: The Earth as seen from the Sun is approximately 1/11,700 radians (about 18 arcseconds ), meaning the solid angle of the Earth as seen from the Sun is approximately 1/175,000,000 of a steradian . Thus the Sun emits about 2.2 billion times the amount of radiation that is caught by Earth, in other words about 3.846×10 watts. Space-based observations of solar irradiance started in 1978. These measurements show that

260-431: The Earth's orbit ( Milankovich cycles ) affect the solar irradiance and insolation (but not the solar constant). The Earth receives a total amount of radiation determined by its cross section (π·R E ), but as it rotates this energy is distributed across the entire surface area (4·π·R E ). Hence the average incoming solar radiation, taking into account the angle at which the rays strike and that at any one moment half

286-744: The MEIDEX payload was to study the temporal and spatial distribution and physical properties of atmospheric desert dust over North Africa , the Mediterranean and the Atlantic Saharan regions. The aim was achieved by a remote sensing experiment operated by the astronauts aboard the shuttle. Also, MEIDEX accomplished diverse secondary science objectives by performing slant visibility observations, sea-surface reflectivity observations, desert surface observations and observations of Transient Luminous Events, better known as sprites. MEIDEX also made

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312-428: The Sun is gradually expanding, and emitting more energy from the resultant larger surface area. The unsolved question of how to account for the clear geological evidence of liquid water on the Earth billions of years ago, at a time when the sun's luminosity was only 70% of its current value, is known as the faint young Sun paradox . At most about 75% of the solar energy actually reaches the earth's surface, as even with

338-540: The Sun. More specifically, it is a flux density measuring mean solar electromagnetic radiation ( total solar irradiance ) per unit area. It is measured on a surface perpendicular to the rays, one astronomical unit (au) from the Sun (roughly the distance from the Sun to the Earth). The solar constant includes radiation over the entire electromagnetic spectrum . It is measured by satellite as being 1.361 kilo watts per square meter (kW/m ) at solar minimum (the time in

364-536: The United States and is the 14th flight of a SEM on the Space Shuttle . The Low Power Transceiver is a compact, flexible device that can be configured to perform custom communications and navigation functions in terrestrial, airborne and space applications. Solar constant The solar constant ( G SC ) measures the amount of energy received by a given area one astronomical unit away from

390-569: The first space observation of a glory . SOLSE-2 was a hyperspectral imaging spectrometer built at the Goddard Space Flight Center that demonstrated a new technique to measure the vertical distribution of ozone in the atmosphere. The first demonstration flight of SOLSE-1 was on STS-87 in 1997. Once proven over a wider range of viewing conditions, the SOLSE-2 technique was incorporated to routinely measure ozone by

416-530: The next generation of weather satellites , including the Ozone Mapping and Profiler Suite (OMPS), that was launched in 2011. The Critical Viscosity of Xenon-2 Experiment measures the viscous behavior of xenon – a heavy, inert gas used in flash lamps and ion rocket engines – at its critical point. The data from the CVX-2 experiment was believed lost in the disaster. The hard drive that carried its data,

442-452: The past 400 years it has varied less than 0.2 percent. Billions of years ago, it was significantly lower . This constant is used in the calculation of radiation pressure , which aids in the calculation of a force on a solar sail . Solar irradiance is measured by satellites above Earth's atmosphere , and is then adjusted using the inverse square law to infer the magnitude of solar irradiance at one Astronomical Unit (au) to evaluate

468-399: The planet does not receive any solar radiation, is one-fourth the solar constant (approximately 340 W/m ). The amount reaching the Earth's surface (as insolation ) is further reduced by atmospheric attenuation, which varies. At any given moment, the amount of solar radiation received at a location on the Earth's surface depends on the state of the atmosphere, the location's latitude , and

494-645: The satellite era (±2% in 1954). Total solar output is now measured as varying (over the last three 11-year sunspot cycles) by approximately 0.1%; see solar variation for details. L = 4 π R s t a r 2 σ T s t a r 4 {\displaystyle L=4\pi R_{\rm {star}}^{2}\sigma T_{\rm {star}}^{4}} L = 4 π f   d 2 {\displaystyle L=4\pi f\ d^{2}} Therefore: 4 π f   d 2 = 4 π R s t

520-497: The solar constant is not constant. It varies with the 11-year sunspot solar cycle . When going further back in time, one has to rely on irradiance reconstructions, using sunspots for the past 400 years or cosmogenic radionuclides for going back 10,000 years. Such reconstructions show that solar irradiance varies with distinct periodicities. These cycles are: 11 years (Schwabe), 88 years (Gleisberg cycle), 208 years (DeVries cycle) and 1,000 years (Eddy cycle). Over billions of years,

546-407: The solar constant. The approximate average value cited, 1.3608 ± 0.0005  kW/m , which is 81.65 kJ/m per minute, is equivalent to approximately 1.951 calories per minute per square centimeter, or 1.951 langleys per minute. Solar output is nearly, but not quite, constant. Variations in total solar irradiance (TSI) were small and difficult to detect accurately with technology available before

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572-451: The time of day. The solar constant includes all wavelengths of solar electromagnetic radiation, not just the visible light (see Electromagnetic spectrum ). It is positively correlated with the apparent magnitude of the Sun which is −26.8. The solar constant and the magnitude of the Sun are two methods of describing the apparent brightness of the Sun, though the magnitude is based on the Sun's visual output only. The angular diameter of

598-457: The title Freestar . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Freestar&oldid=1021754624 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Freestar experiment It

624-509: The value during a solar cycle . SOLCON measures the solar irradiance in space to avoid perturbations by the atmosphere of the Earth . It is also used as a reference to construct a long-duration time series of the solar irradiance . This data will ensure continuity of the solar constant level obtained by instruments mounted on free flyers, over climate time-scale duration. The SEM is made up of 11 separate student experiments from schools across

650-406: Was erroneously applied. Abbot's results varied between 1.89 and 2.22 calories (1.318 to 1.548  kW/m ), a variation that appeared to be due to the Sun and not the Earth's atmosphere. In 1954 the solar constant was evaluated as 2.00 cal/min/cm ± 2%. Current results are about 2.5 percent lower. The actual direct solar irradiance at the top of the atmosphere fluctuates by about 6.9% during

676-554: Was mounted on a crossbay Hitchhiker Multipurpose Equipment Support Structure in the Shuttle's payload bay during the STS-107 flight, which ended with the disintegration of Columbia during re-entry into the Earth's atmosphere. Although data was lost in the re-entry, much of the data collected while in space, such as that from MEIDEX, had already been transmitted to ground stations. The six experiments were: The primary mission of

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