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151-542: The original mission duration was to be only three years, but was extended several times. When the mission finally ended in June 2005 due to funding cuts, 14 years after the satellite's launch, six of its ten instruments were still operational. A final orbit-lowering burn was performed in early December 2005 to prepare the satellite for deorbit. On 26 October 2010, the International Space Station performed

302-572: A Proton rocket on 20 November 1998. Zarya provided propulsion, attitude control , communications, and electrical power. Two weeks later on 4 December 1998, the American-made Unity was ferried aboard Space Shuttle Endeavour on STS-88 and joined with Zarya . Unity provided the connection between the Russian and US segments of the station and would provide ports to connect future modules and visiting spacecraft. While

453-690: A virtual reality exhibit called The Infinite featuring life aboard the ISS was announced. The International Space Station is a product of global collaboration, with its components manufactured across the world. The modules of the Russian Orbital Segment , including Zarya and Zvezda , were produced at the Khrunichev State Research and Production Space Center in Moscow. Zvezda was initially manufactured in 1985 as

604-475: A "shorter version" of MARS-500 may be carried out on the ISS. In 2009, noting the value of the partnership framework itself, Sergey Krasnov wrote, "When compared with partners acting separately, partners developing complementary abilities and resources could give us much more assurance of the success and safety of space exploration. The ISS is helping further advance near-Earth space exploration and realisation of prospective programmes of research and exploration of

755-427: A 1:1 mixture of HCl and H 2 O, the system separates completely into two separate liquid phases. Hydrochloric acid forms an azeotrope with boiling point 108.58 °C at 20.22 g HCl per 100 g solution; thus hydrochloric acid cannot be concentrated beyond this point by distillation. Unlike hydrogen fluoride, anhydrous liquid hydrogen chloride is difficult to work with as a solvent, because its boiling point

906-430: A chlorine derivative of perchloric acid (HOClO 3 ), similar to the thermally unstable chlorine derivatives of other oxoacids: examples include chlorine nitrate (ClONO 2 , vigorously reactive and explosive), and chlorine fluorosulfate (ClOSO 2 F, more stable but still moisture-sensitive and highly reactive). Dichlorine hexoxide is a dark-red liquid that freezes to form a solid which turns yellow at −180 °C: it

1057-414: A chlorofluorinating agent, adding chlorine and fluorine across a multiple bond or by oxidation: for example, it will attack carbon monoxide to form carbonyl chlorofluoride, COFCl. It will react analogously with hexafluoroacetone , (CF 3 ) 2 CO, with a potassium fluoride catalyst to produce heptafluoroisopropyl hypochlorite, (CF 3 ) 2 CFOCl; with nitriles RCN to produce RCF 2 NCl 2 ; and with

1208-777: A component for the Mir-2 space station, which was never launched. Much of the US Orbital Segment , including the Destiny and Unity modules, the Integrated Truss Structure , and solar arrays , were built at NASA's Marshall Space Flight Center in Huntsville, Alabama and Michoud Assembly Facility in New Orleans . These components underwent final assembly and processing for launch at

1359-747: A dangerously powerful and unstable oxidizer. Near the end of the nineteenth century, E. S. Smith patented a method of sodium hypochlorite production involving electrolysis of brine to produce sodium hydroxide and chlorine gas, which then mixed to form sodium hypochlorite. This is known as the chloralkali process , first introduced on an industrial scale in 1892, and now the source of most elemental chlorine and sodium hydroxide. In 1884 Chemischen Fabrik Griesheim of Germany developed another chloralkali process which entered commercial production in 1888. Elemental chlorine solutions dissolved in chemically basic water (sodium and calcium hypochlorite ) were first used as anti- putrefaction agents and disinfectants in

1510-405: A debris-avoidance maneuver in response to a conjunction with UARS. The decommissioned satellite re-entered Earth's atmosphere on 24 September 2011. Considerable media attention surrounded the event, largely due to NASA's predictions that substantial parts of the satellite might reach the ground, potentially endangering inhabited areas. However, the satellite ultimately impacted in a remote area of

1661-554: A dozen Japanese universities conducted experiments in diverse fields. Cultural activities are another major objective of the ISS programme. Tetsuo Tanaka, the director of JAXA's Space Environment and Utilization Center, has said: "There is something about space that touches even people who are not interested in science." Amateur Radio on the ISS (ARISS) is a volunteer programme that encourages students worldwide to pursue careers in science, technology, engineering, and mathematics, through amateur radio communications opportunities with

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1812-458: A few minutes of the previous reading. The instrument consists of an interferometer which feeds to a CCD camera. The two telescopes (45 degrees and 135 degrees) each have a one meter long baffle tube to reduce stray light during daytime viewing. The input from the telescopes is positioned side by side on the CCD so both views are imaged simultaneously. SUSIM measured ultraviolet (UV) emissions from

1963-445: A fluoride ion donor or acceptor (Lewis base or acid), although it does not dissociate appreciably into ClF 2 and ClF 4 ions. Chlorine pentafluoride (ClF 5 ) is made on a large scale by direct fluorination of chlorine with excess fluorine gas at 350 °C and 250 atm, and on a small scale by reacting metal chlorides with fluorine gas at 100–300 °C. It melts at −103 °C and boils at −13.1 °C. It

2114-532: A function of pressure, from the tropopause to the mesopause , with good accuracy and spatial resolution, and hence to study the structure and dynamics of the region, (ii) To investigate the distribution and variability of water vapour in the middle atmosphere, to determine its role in the atmospheric general circulation, and its sources and sinks in the middle atmosphere, (iii) To measure the global distribution of oxides of nitrogen and hence to investigate their origins and their roles in catalytic cycles which control

2265-468: A higher oxidation state than bromination with Br 2 when multiple oxidation states are available, such as in MoCl 5 and MoBr 3 . Chlorides can be made by reaction of an element or its oxide, hydroxide, or carbonate with hydrochloric acid, and then dehydrated by mildly high temperatures combined with either low pressure or anhydrous hydrogen chloride gas. These methods work best when the chloride product

2416-650: A lengthy interplanetary cruise, such as the six-month interval required to travel to Mars . Medical studies are conducted aboard the ISS on behalf of the National Space Biomedical Research Institute (NSBRI). Prominent among these is the Advanced Diagnostic Ultrasound in Microgravity study in which astronauts perform ultrasound scans under the guidance of remote experts. The study considers

2567-481: A location in the relative safety of low Earth orbit to test spacecraft systems that will be required for long-duration missions to the Moon and Mars. This provides experience in operations, maintenance, and repair and replacement activities on-orbit. This will help develop essential skills in operating spacecraft farther from Earth, reduce mission risks, and advance the capabilities of interplanetary spacecraft. Referring to

2718-784: A low-pressure discharge tube. The yellow [Cl 3 ] cation is more stable and may be produced as follows: This reaction is conducted in the oxidising solvent arsenic pentafluoride . The trichloride anion, [Cl 3 ] , has also been characterised; it is analogous to triiodide . The three fluorides of chlorine form a subset of the interhalogen compounds, all of which are diamagnetic . Some cationic and anionic derivatives are known, such as ClF 2 , ClF 4 , ClF 2 , and Cl 2 F . Some pseudohalides of chlorine are also known, such as cyanogen chloride (ClCN, linear), chlorine cyanate (ClNCO), chlorine thiocyanate (ClSCN, unlike its oxygen counterpart), and chlorine azide (ClN 3 ). Chlorine monofluoride (ClF)

2869-519: A reduction in oxidation state , which can also be achieved by reducing a higher chloride using hydrogen or a metal as a reducing agent. This may also be achieved by thermal decomposition or disproportionation as follows: Most metal chlorides with the metal in low oxidation states (+1 to +3) are ionic. Nonmetals tend to form covalent molecular chlorides, as do metals in high oxidation states from +3 and above. Both ionic and covalent chlorides are known for metals in oxidation state +3 (e.g. scandium chloride

3020-408: A result of the increasing molecular weight of the halogens down the group, the density and heats of fusion and vaporisation of chlorine are again intermediate between those of bromine and fluorine, although all their heats of vaporisation are fairly low (leading to high volatility) thanks to their diatomic molecular structure. The halogens darken in colour as the group is descended: thus, while fluorine

3171-488: A separate gaseous substance was recognised by the Brabantian chemist and physician Jan Baptist van Helmont . The element was first studied in detail in 1774 by Swedish chemist Carl Wilhelm Scheele , and he is credited with the discovery. Scheele produced chlorine by reacting MnO 2 (as the mineral pyrolusite ) with HCl: Scheele observed several of the properties of chlorine: the bleaching effect on litmus ,

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3322-555: A series of education guides, students develop a deeper understanding of the past and near-term future of crewed space flight, as well as that of Earth and life. In the JAXA "Seeds in Space" experiments, the mutation effects of spaceflight on plant seeds aboard the ISS are explored by growing sunflower seeds that have flown on the ISS for about nine months. In the first phase of Kibō utilisation from 2008 to mid-2010, researchers from more than

3473-625: A solution of sodium carbonate. The resulting liquid, known as " Eau de Javel " (" Javel water "), was a weak solution of sodium hypochlorite . This process was not very efficient, and alternative production methods were sought. Scottish chemist and industrialist Charles Tennant first produced a solution of calcium hypochlorite ("chlorinated lime"), then solid calcium hypochlorite (bleaching powder). These compounds produced low levels of elemental chlorine and could be more efficiently transported than sodium hypochlorite, which remained as dilute solutions because when purified to eliminate water, it became

3624-519: A third set of arrays were delivered on STS-116 , STS-117 , and STS-118 . As a result of the major expansion of the station's power-generating capabilities, more modules could be accommodated, and the US Harmony module and Columbus European laboratory were added. These were soon followed by the first two components of the Japanese Kibō laboratory. In March 2009, STS-119 completed

3775-445: A wide range of free teaching materials that can be downloaded for use in classrooms. In one lesson, students can navigate a 3D model of the interior and exterior of the ISS, and face spontaneous challenges to solve in real time. The Japanese Aerospace Exploration Agency (JAXA) aims to inspire children to "pursue craftsmanship" and to heighten their "awareness of the importance of life and their responsibilities in society". Through

3926-416: Is hydrogen chloride , HCl, a major chemical in industry as well as in the laboratory, both as a gas and dissolved in water as hydrochloric acid . It is often produced by burning hydrogen gas in chlorine gas, or as a byproduct of chlorinating hydrocarbons . Another approach is to treat sodium chloride with concentrated sulfuric acid to produce hydrochloric acid, also known as the "salt-cake" process: In

4077-441: Is sodium chlorate , mostly used to make chlorine dioxide to bleach paper pulp. The decomposition of chlorate to chloride and oxygen is a common way to produce oxygen in the laboratory on a small scale. Chloride and chlorate may comproportionate to form chlorine as follows: Perchlorates and perchloric acid (HOClO 3 ) are the most stable oxo-compounds of chlorine, in keeping with the fact that chlorine compounds are most stable when

4228-474: Is a pale yellow gas, chlorine is distinctly yellow-green. This trend occurs because the wavelengths of visible light absorbed by the halogens increase down the group. Specifically, the colour of a halogen, such as chlorine, results from the electron transition between the highest occupied antibonding π g molecular orbital and the lowest vacant antibonding σ u molecular orbital. The colour fades at low temperatures, so that solid chlorine at −195 °C

4379-399: Is a poor solvent, only able to dissolve small molecular compounds such as nitrosyl chloride and phenol , or salts with very low lattice energies such as tetraalkylammonium halides. It readily protonates electrophiles containing lone-pairs or π bonds. Solvolysis , ligand replacement reactions, and oxidations are well-characterised in hydrogen chloride solution: Nearly all elements in

4530-486: Is a very poor conductor of electricity, and indeed its conductivity is so low as to be practically unmeasurable. Chlorine has two stable isotopes, Cl and Cl. These are its only two natural isotopes occurring in quantity, with Cl making up 76% of natural chlorine and Cl making up the remaining 24%. Both are synthesised in stars in the oxygen-burning and silicon-burning processes . Both have nuclear spin 3/2+ and thus may be used for nuclear magnetic resonance , although

4681-432: Is a very strong fluorinating agent, although it is still not as effective as chlorine trifluoride. Only a few specific stoichiometric reactions have been characterised. Arsenic pentafluoride and antimony pentafluoride form ionic adducts of the form [ClF 4 ] [MF 6 ] (M = As, Sb) and water reacts vigorously as follows: The product, chloryl fluoride , is one of the five known chlorine oxide fluorides. These range from

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4832-442: Is a weak ligand, weaker than water, a few compounds involving coordinated ClO 4 are known. The Table below presents typical oxidation states for chlorine element as given in the secondary schools or colleges. There are more complex chemical compounds, the structure of which can only be explained using modern quantum chemical methods, for example, cluster technetium chloride [(CH 3 ) 4 N] 3 [Tc 6 Cl 14 ], in which 6 of

4983-506: Is almost colourless. Like solid bromine and iodine, solid chlorine crystallises in the orthorhombic crystal system , in a layered lattice of Cl 2 molecules. The Cl–Cl distance is 198 pm (close to the gaseous Cl–Cl distance of 199 pm) and the Cl···Cl distance between molecules is 332 pm within a layer and 382 pm between layers (compare the van der Waals radius of chlorine, 180 pm). This structure means that chlorine

5134-472: Is also produced when photolysing the solid at −78 °C: it is a dark brown solid that explodes below 0 °C. The ClO radical leads to the depletion of atmospheric ozone and is thus environmentally important as follows: Chlorine perchlorate (ClOClO 3 ) is a pale yellow liquid that is less stable than ClO 2 and decomposes at room temperature to form chlorine, oxygen, and dichlorine hexoxide (Cl 2 O 6 ). Chlorine perchlorate may also be considered

5285-401: Is an accepted version of this page The International Space Station ( ISS ) is a large space station that was assembled and is maintained in low Earth orbit by a collaboration of five space agencies and their contractors: NASA (United States), Roscosmos (Russia), ESA (Europe), JAXA (Japan), and CSA (Canada). The ISS is the largest space station ever built. Its primary purpose

5436-431: Is an important ISS research activity, with the objective of reaping economic benefits through the improvement of techniques used on Earth. Other areas of interest include the effect of low gravity on combustion, through the study of the efficiency of burning and control of emissions and pollutants. These findings may improve knowledge about energy production and lead to economic and environmental benefits. The ISS provides

5587-658: Is even more unstable and cannot be isolated or concentrated without decomposition: it is known from the decomposition of aqueous chlorine dioxide. However, sodium chlorite is a stable salt and is useful for bleaching and stripping textiles, as an oxidising agent, and as a source of chlorine dioxide. Chloric acid (HOClO 2 ) is a strong acid that is quite stable in cold water up to 30% concentration, but on warming gives chlorine and chlorine dioxide. Evaporation under reduced pressure allows it to be concentrated further to about 40%, but then it decomposes to perchloric acid, chlorine, oxygen, water, and chlorine dioxide. Its most important salt

5738-894: Is extremely dangerous, and poisonous to most living organisms. As a chemical warfare agent, chlorine was first used in World War ;I as a poison gas weapon. In the form of chloride ions , chlorine is necessary to all known species of life. Other types of chlorine compounds are rare in living organisms, and artificially produced chlorinated organics range from inert to toxic. In the upper atmosphere , chlorine-containing organic molecules such as chlorofluorocarbons have been implicated in ozone depletion . Small quantities of elemental chlorine are generated by oxidation of chloride ions in neutrophils as part of an immune system response against bacteria. The most common compound of chlorine, sodium chloride, has been known since ancient times; archaeologists have found evidence that rock salt

5889-551: Is extremely thermally stable, and is sold commercially in 500-gram steel lecture bottles. It is a colourless gas that melts at −155.6 °C and boils at −100.1 °C. It may be produced by the reaction of its elements at 225 °C, though it must then be separated and purified from chlorine trifluoride and its reactants. Its properties are mostly intermediate between those of chlorine and fluorine. It will react with many metals and nonmetals from room temperature and above, fluorinating them and liberating chlorine. It will also act as

6040-575: Is highly resistant to environmental hazards , were found to survive for three years in outer space , based on studies conducted on the International Space Station. These findings supported the notion of panspermia , the hypothesis that life exists throughout the Universe , distributed in various ways, including space dust , meteoroids , asteroids , comets , planetoids or contaminated spacecraft . Remote sensing of

6191-534: Is intended to detect dark matter and answer other fundamental questions about our universe. According to NASA, the AMS is as important as the Hubble Space Telescope . Currently docked on station, it could not have been easily accommodated on a free flying satellite platform because of its power and bandwidth needs. On 3 April 2013, scientists reported that hints of dark matter may have been detected by

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6342-515: Is less reactive than fluorine and more reactive than bromine. It is also a weaker oxidising agent than fluorine, but a stronger one than bromine. Conversely, the chloride ion is a weaker reducing agent than bromide, but a stronger one than fluoride. It is intermediate in atomic radius between fluorine and bromine, and this leads to many of its atomic properties similarly continuing the trend from iodine to bromine upward, such as first ionisation energy , electron affinity , enthalpy of dissociation of

6493-442: Is less than +1.395 V, it would be expected that chlorine should be able to oxidise water to oxygen and hydrochloric acid. However, the kinetics of this reaction are unfavorable, and there is also a bubble overpotential effect to consider, so that electrolysis of aqueous chloride solutions evolves chlorine gas and not oxygen gas, a fact that is very useful for the industrial production of chlorine. The simplest chlorine compound

6644-501: Is likely to be a global effort." Currently, US federal legislation prevents NASA co-operation with China on space projects without approval by the FBI and Congress. The ISS crew provides opportunities for students on Earth by running student-developed experiments, making educational demonstrations, allowing for student participation in classroom versions of ISS experiments, and directly engaging students using radio, and email. ESA offers

6795-479: Is low, it has a small liquid range, its dielectric constant is low and it does not dissociate appreciably into H 2 Cl and HCl 2 ions – the latter, in any case, are much less stable than the bifluoride ions ( HF 2 ) due to the very weak hydrogen bonding between hydrogen and chlorine, though its salts with very large and weakly polarising cations such as Cs and NR 4 (R = Me , Et , Bu ) may still be isolated. Anhydrous hydrogen chloride

6946-437: Is made by reacting anhydrous sodium perchlorate or barium perchlorate with concentrated hydrochloric acid, filtering away the chloride precipitated and distilling the filtrate to concentrate it. Anhydrous perchloric acid is a colourless mobile liquid that is sensitive to shock that explodes on contact with most organic compounds, sets hydrogen iodide and thionyl chloride on fire and even oxidises silver and gold. Although it

7097-427: Is mostly ionic, but aluminium chloride is not). Silver chloride is very insoluble in water and is thus often used as a qualitative test for chlorine. Although dichlorine is a strong oxidising agent with a high first ionisation energy, it may be oxidised under extreme conditions to form the [Cl 2 ] cation. This is very unstable and has only been characterised by its electronic band spectrum when produced in

7248-415: Is one of the most reactive elements. Chlorine is a weaker oxidising agent than fluorine but a stronger one than bromine or iodine. This can be seen from the standard electrode potentials of the X 2 /X couples (F, +2.866  V; Cl, +1.395 V; Br, +1.087  V; I, +0.615 V; At , approximately +0.3  V). However, this trend is not shown in the bond energies because fluorine

7399-400: Is present in solid crystalline hydrogen chloride at low temperatures, similar to the hydrogen fluoride structure, before disorder begins to prevail as the temperature is raised. Hydrochloric acid is a strong acid (p K a = −7) because the hydrogen bonds to chlorine are too weak to inhibit dissociation. The HCl/H 2 O system has many hydrates HCl· n H 2 O for n = 1, 2, 3, 4, and 6. Beyond

7550-419: Is produced in the atmosphere by spallation of Ar by interactions with cosmic ray protons . In the top meter of the lithosphere , Cl is generated primarily by thermal neutron activation of Cl and spallation of K and Ca . In the subsurface environment, muon capture by Ca becomes more important as a way to generate Cl. Chlorine is intermediate in reactivity between fluorine and bromine, and

7701-401: Is quite slow at temperatures below 70 °C in spite of the very favourable equilibrium constant of 10 . The chlorate ions may themselves disproportionate to form chloride and perchlorate (4 ClO 3 ⇌ Cl + 3 ClO 4 ) but this is still very slow even at 100 °C despite the very favourable equilibrium constant of 10 . The rates of reaction for the chlorine oxyanions increases as

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7852-510: Is singular due to its small size, low polarisability, and inability to show hypervalence . As another difference, chlorine has a significant chemistry in positive oxidation states while fluorine does not. Chlorination often leads to higher oxidation states than bromination or iodination but lower oxidation states than fluorination. Chlorine tends to react with compounds including M–M, M–H, or M–C bonds to form M–Cl bonds. Given that E°( ⁠ 1 / 2 ⁠ O 2 /H 2 O) = +1.229 V, which

8003-567: Is stable to hydrolysis; otherwise, the possibilities include high-temperature oxidative chlorination of the element with chlorine or hydrogen chloride, high-temperature chlorination of a metal oxide or other halide by chlorine, a volatile metal chloride, carbon tetrachloride , or an organic chloride. For instance, zirconium dioxide reacts with chlorine at standard conditions to produce zirconium tetrachloride , and uranium trioxide reacts with hexachloropropene when heated under reflux to give uranium tetrachloride . The second example also involves

8154-553: Is the anhydride of perchloric acid (HClO 4 ) and can readily be obtained from it by dehydrating it with phosphoric acid at −10 °C and then distilling the product at −35 °C and 1 mmHg. It is a shock-sensitive, colourless oily liquid. It is the least reactive of the chlorine oxides, being the only one to not set organic materials on fire at room temperature. It may be dissolved in water to regenerate perchloric acid or in aqueous alkalis to regenerate perchlorates. However, it thermally decomposes explosively by breaking one of

8305-430: Is the anhydride. It is thus an effective bleach and is mostly used to make hypochlorites . It explodes on heating or sparking or in the presence of ammonia gas. Chlorine dioxide (ClO 2 ) was the first chlorine oxide to be discovered in 1811 by Humphry Davy . It is a yellow paramagnetic gas (deep-red as a solid or liquid), as expected from its having an odd number of electrons: it is stable towards dimerisation due to

8456-559: Is to perform microgravity and space environment experiments. Operationally, the station is divided into two sections: the Russian Orbital Segment (ROS) assembled by Roscosmos, and the US Orbital Segment (USOS), assembled by NASA, JAXA, ESA and CSA. A striking feature of the ISS is the Integrated Truss Structure , which connects the large solar panels and radiators to the pressurized modules. The pressurized modules are specialized for research, habitation, storage, spacecraft control, and airlock functions. Visiting spacecraft dock at

8607-472: Is usually made by reaction of chlorine dioxide with oxygen. Despite attempts to rationalise it as the dimer of ClO 3 , it reacts more as though it were chloryl perchlorate, [ClO 2 ] [ClO 4 ] , which has been confirmed to be the correct structure of the solid. It hydrolyses in water to give a mixture of chloric and perchloric acids: the analogous reaction with anhydrous hydrogen fluoride does not proceed to completion. Dichlorine heptoxide (Cl 2 O 7 )

8758-631: The Prichal module, docked in November 2021. As of November 2021, the station consists of 18 pressurised modules (including airlocks) and the Integrated Truss Structure. The ISS functions as a modular space station, enabling the addition or removal of modules from its structure for increased adaptability. Chlorine Chlorine is a chemical element ; it has symbol Cl and atomic number 17. The second-lightest of

8909-510: The Canadarm2 and Dextre , a joint Canadian-U.S. endeavor. All of these components were shipped to the SSPF for launch processing. The assembly of the International Space Station, a major endeavour in space architecture , began in November 1998. Modules in the Russian segment launched and docked autonomously, with the exception of Rassvet . Other modules and components were delivered by

9060-581: The Columbus programme, the most ambitious effort in space undertaken by that organization at the time. The plan spearheaded by Germany and Italy included a module which would be attached to Freedom , and with the capability to evolve into a full-fledged European orbital outpost before the end of the century. Increasing costs threw these plans into doubt in the early 1990s. Congress was unwilling to provide enough money to build and operate Freedom , and demanded NASA increase international participation to defray

9211-537: The MARS-500 experiment, a crew isolation experiment conducted on Earth, ESA states, "Whereas the ISS is essential for answering questions concerning the possible impact of weightlessness, radiation and other space-specific factors, aspects such as the effect of long-term isolation and confinement can be more appropriately addressed via ground-based simulations". Sergey Krasnov, the head of human space flight programmes for Russia's space agency, Roscosmos, in 2011 suggested

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9362-577: The Monitor of All-sky X-ray Image (MAXI) , and the Alpha Magnetic Spectrometer . Gravity at the altitude of the ISS is approximately 90% as strong as at Earth's surface, but objects in orbit are in a continuous state of freefall , resulting in an apparent state of weightlessness . This perceived weightlessness is disturbed by five effects: Researchers are investigating the effect of the station's near-weightless environment on

9513-1034: The Operations and Checkout Building and the Space Station Processing Facility (SSPF) at the Kennedy Space Center in Florida. The US Orbital Segment also hosts the Columbus module contributed by the European Space Agency and built in Germany, the Kibō module contributed by Japan and built at the Tsukuba Space Center and the Institute of Space and Astronautical Science , along with

9664-478: The Pacific Ocean . CLAES was a spectrometer that determined the concentrations and distributions of nitrogen and chlorine compounds, ozone , water vapor and methane . This platform produced the first global maps of ozone depleting chlorinated compounds. It did this by inferring the amount of gases in the atmosphere by measuring the unique infrared signature of each gas. In order to differentiate

9815-543: The Space Shuttle , which then had to be installed by astronauts either remotely using robotic arms or during spacewalks, more formally known as extra-vehicular activities (EVAs). By 5 June 2011 astronauts had made over 159 EVAs to add components to the station, totaling more than 1,000 hours in space. The foundation for the ISS was laid with the launch of the Russian-built Zarya module atop

9966-465: The halogens , it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent : among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale , behind only oxygen and fluorine. Chlorine played an important role in

10117-473: The neutron activation of natural chlorine. The most stable chlorine radioisotope is Cl. The primary decay mode of isotopes lighter than Cl is electron capture to isotopes of sulfur ; that of isotopes heavier than Cl is beta decay to isotopes of argon ; and Cl may decay by either mode to stable S or Ar. Cl occurs in trace quantities in nature as a cosmogenic nuclide in a ratio of about (7–10) × 10 to 1 with stable chlorine isotopes: it

10268-483: The noble gases xenon and radon do not escape fluorination. An impermeable fluoride layer is formed by sodium , magnesium , aluminium , zinc , tin , and silver , which may be removed by heating. Nickel , copper, and steel containers are usually used due to their great resistance to attack by chlorine trifluoride, stemming from the formation of an unreactive layer of metal fluoride. Its reaction with hydrazine to form hydrogen fluoride, nitrogen, and chlorine gases

10419-549: The orbit of UARS had reduced to 175 by 185 km (109 by 115 mi). 26 pieces of debris were expected to survive reentry and strike the surface, the largest of which had an estimated mass of 158.30 kg (348.99 lb), possibly reaching the surface at a velocity of 44 meters per second (140 ft/s) (98 mph; 160 km/h). Smaller pieces were expected to strike the surface at up to 107 metres per second (350 ft/s) (240 mph; 390 km/h). At 07:46 UTC on 24 September 2011, NASA released an updated statement on

10570-414: The 14 chlorine atoms are formally divalent, and oxidation states are fractional. In addition, all the above chemical regularities are valid for "normal" or close to normal conditions, while at ultra-high pressures (for example, in the cores of large planets), chlorine can exhibit an oxidation state of -3, forming a Na3Cl compound with sodium, which does not fit into traditional concepts of chemistry. Like

10721-545: The 1820s, in France, long before the establishment of the germ theory of disease . This practice was pioneered by Antoine-Germain Labarraque , who adapted Berthollet's "Javel water" bleach and other chlorine preparations. Elemental chlorine has since served a continuous function in topical antisepsis (wound irrigation solutions and the like) and public sanitation, particularly in swimming and drinking water. Chlorine gas

10872-407: The 1975 Apollo-Soyuz Test Project , the first docking of spacecraft from two different spacefaring nations. The ASTP was considered a success, and further joint missions were also contemplated. One such concept was International Skylab, which proposed launching the backup Skylab B space station for a mission that would see multiple visits by both Apollo and Soyuz crew vehicles. More ambitious

11023-472: The 63 and 205 GHz radiometers remained operational, but the 183 GHz radiometer failed after 19 months of operation. HALOE uses solar occultation to measure simultaneous vertical profiles of ozone (O 3 ), hydrogen chloride (HCl), hydrogen fluoride (HF), methane (CH 4 ), water vapor (H 2 O), nitric oxide (NO), nitrogen dioxide (NO 2 ), temperature, aerosol extinction, aerosol composition and size distribution versus atmospheric pressure at

11174-785: The AMS. According to the scientists, "The first results from the space-borne Alpha Magnetic Spectrometer confirm an unexplained excess of high-energy positrons in Earth-bound cosmic rays". The space environment is hostile to life. Unprotected presence in space is characterised by an intense radiation field (consisting primarily of protons and other subatomic charged particles from the solar wind , in addition to cosmic rays ), high vacuum, extreme temperatures, and microgravity. Some simple forms of life called extremophiles , as well as small invertebrates called tardigrades can survive in this environment in an extremely dry state through desiccation . Medical research improves knowledge about

11325-525: The Earth's crust is in the form of ionic chloride compounds, which includes table salt. It is the second-most abundant halogen (after fluorine) and 20th most abundant element in Earth's crust. These crystal deposits are nevertheless dwarfed by the huge reserves of chloride in seawater. Elemental chlorine is commercially produced from brine by electrolysis , predominantly in the chloralkali process . The high oxidising potential of elemental chlorine led to

11476-399: The Earth's limb. The measurements are done at eight different wavelengths of infrared across a 1.6 km (0.99 mi) wide field of view of Earth's limb. A vertical scan of the atmosphere was obtained by tracking the sun during occultation. The scan will measure the amount of solar energy absorbed by gases in the atmosphere. In order to support scanning, the instrument came in two parts,

11627-474: The Earth, astronomy, and deep space research on the ISS have significantly increased during the 2010s after the completion of the US Orbital Segment in 2011. Throughout the more than 20 years of the ISS program, researchers aboard the ISS and on the ground have examined aerosols , ozone , lightning , and oxides in Earth's atmosphere, as well as the Sun , cosmic rays, cosmic dust , antimatter , and dark matter in

11778-541: The German and Dutch names of oxygen : sauerstoff or zuurstof , both translating into English as acid substance ), so a number of chemists, including Claude Berthollet , suggested that Scheele's dephlogisticated muriatic acid air must be a combination of oxygen and the yet undiscovered element, muriaticum . In 1809, Joseph Louis Gay-Lussac and Louis-Jacques Thénard tried to decompose dephlogisticated muriatic acid air by reacting it with charcoal to release

11929-491: The Greek word χλωρος ( chlōros , "green-yellow"), in reference to its colour. The name " halogen ", meaning "salt producer", was originally used for chlorine in 1811 by Johann Salomo Christoph Schweigger . This term was later used as a generic term to describe all the elements in the chlorine family (fluorine, bromine, iodine), after a suggestion by Jöns Jakob Berzelius in 1826. In 1823, Michael Faraday liquefied chlorine for

12080-531: The ISS crew. ARISS is an international working group, consisting of delegations from nine countries including several in Europe, as well as Japan, Russia, Canada, and the United States. In areas where radio equipment cannot be used, speakerphones connect students to ground stations which then connect the calls to the space station. First Orbit is a 2011 feature-length documentary film about Vostok 1 ,

12231-606: The ISS was given additional roles of serving commercial, diplomatic, and educational purposes. The ISS provides a platform to conduct scientific research, with power, data, cooling, and crew available to support experiments. Small uncrewed spacecraft can also provide platforms for experiments, especially those involving zero gravity and exposure to space, but space stations offer a long-term environment where studies can be performed potentially for decades, combined with ready access by human researchers. The ISS simplifies individual experiments by allowing groups of experiments to share

12382-734: The Integrated Truss Structure with the installation of the fourth and final set of solar arrays. The final section of Kibō was delivered in July 2009 on STS-127 , followed by the Russian Poisk module. The US Tranquility module was delivered in February 2010 during STS-130 , alongside the Cupola , followed by the penultimate Russian module, Rassvet , in May 2010. Rassvet was delivered by Space Shuttle Atlantis on STS-132 in exchange for

12533-543: The Joint Space Operations Center later announced that the reentry took place at 04:00 UTC on 24 September, at 14°06′S 170°06′W  /  14.1°S 170.1°W  / -14.1; -170.1 , just downrange of American Samoa . According to NASA, the satellite's debris field would extend between positions 300 and 800 miles (480 and 1,300 km) downrange , generally northeast of this position. International Space Station This

12684-684: The Russian Proton delivery of the US-funded Zarya module in 1998. The last pressurised module of the USOS, Leonardo , was brought to the station in February 2011 on the final flight of Discovery , STS-133 . Russia's new primary research module Nauka docked in July 2021, along with the European Robotic Arm which can relocate itself to different parts of the Russian modules of the station. Russia's latest addition,

12835-485: The Russian State Archive. Nespoli is credited as the director of photography for this documentary film, as he recorded the majority of the footage himself during Expedition 26 / 27 . The film was streamed in a global YouTube premiere in 2011 under a free licence through the website firstorbit.org . In May 2013, commander Chris Hadfield shot a music video of David Bowie 's " Space Oddity " on board

12986-694: The Salyut and Mir space stations. In 1984 the ESA was invited to participate in Space Station Freedom , and the ESA approved the Columbus laboratory by 1987. The Japanese Experiment Module (JEM), or Kibō , was announced in 1985, as part of the Freedom space station in response to a NASA request in 1982. In early 1985, science ministers from the European Space Agency (ESA) countries approved

13137-500: The Solar system, including the Moon and Mars." A crewed mission to Mars may be a multinational effort involving space agencies and countries outside the current ISS partnership. In 2010, ESA Director-General Jean-Jacques Dordain stated his agency was ready to propose to the other four partners that China, India, and South Korea be invited to join the ISS partnership. NASA chief Charles Bolden stated in February 2011, "Any mission to Mars

13288-515: The Soviet Union. The first ISS module was launched in 1998. Major modules have been launched by Proton and Soyuz rockets and by the Space Shuttle launch system. The first long-term residents, Expedition 1 , arrived on 2 November 2000. Since then, the station has been continuously occupied for 24 years and 26 days, the longest continuous human presence in space. As of March 2024 , 279 individuals from 22 countries have visited

13439-596: The UARS website, stating that: "The Joint Space Operations Center at Vandenberg Air Force Base in California said the satellite penetrated the atmosphere over the Pacific Ocean". A precise re-entry time and location was not initially stated. Nicholas Johnson, the chief orbital debris scientist at NASA's Johnson Space Center , stated that "We don't know where the debris field might be... We may never know." However,

13590-496: The X 2 molecule (X = Cl, Br, I), ionic radius, and X–X bond length. (Fluorine is anomalous due to its small size.) All four stable halogens experience intermolecular van der Waals forces of attraction, and their strength increases together with the number of electrons among all homonuclear diatomic halogen molecules. Thus, the melting and boiling points of chlorine are intermediate between those of fluorine and bromine: chlorine melts at −101.0 °C and boils at −34.0 °C. As

13741-415: The amount of ozone in the stratospheric ozone layer. It also made extensive observations of volcanic aerosols and polar stratospheric clouds in the middle atmosphere. The instrument operated from September 1991–July 1992. The MLS detected naturally occurring microwave thermal emissions from Earth's limb to create vertical profiles of atmospheric gases, temperature, pressure and cloud ice. MLS looks 90° from

13892-660: The angle of UARS' orbit. Thermal radiation enters the instrument through a three-mirror antenna system. The antenna mechanically scans in the vertical plane through the atmospheric limb every 65.5 seconds. The scan covers a height range from the surface up to 90 km (55 miles). Upon entering the instrument, the signal from the antenna is separated into three signals for processing by different radiometers. The 63 GHz radiometer measures temperature and pressure. The 183 GHz radiometer measures water vapor and ozone. The 205 GHz radiometer measures ClO , ozone, sulfur dioxide , nitric acid and water vapor. As late as June 2005,

14043-606: The central Cl–O bonds, producing the radicals ClO 3 and ClO 4 which immediately decompose to the elements through intermediate oxides. Chlorine forms four oxoacids: hypochlorous acid (HOCl), chlorous acid (HOClO), chloric acid (HOClO 2 ), and perchloric acid (HOClO 3 ). As can be seen from the redox potentials given in the adjacent table, chlorine is much more stable towards disproportionation in acidic solutions than in alkaline solutions: The hypochlorite ions also disproportionate further to produce chloride and chlorate (3 ClO ⇌ 2 Cl + ClO 3 ) but this reaction

14194-424: The chlorine atom is in its lowest (−1) or highest (+7) possible oxidation states. Perchloric acid and aqueous perchlorates are vigorous and sometimes violent oxidising agents when heated, in stark contrast to their mostly inactive nature at room temperature due to the high activation energies for these reactions for kinetic reasons. Perchlorates are made by electrolytically oxidising sodium chlorate, and perchloric acid

14345-539: The connection of two modules built on different continents, by nations that were once bitter rivals was a significant milestone, these two initial modules lacked life support systems and the ISS remained unmanned for the next two years. At the time, the Russian station Mir was still inhabited. The turning point arrived in July 2000 with the launch of the Zvezda module. Equipped with living quarters and life-support systems, Zvezda enabled continuous human presence aboard

14496-429: The dark. Crystalline clathrate hydrates ClO 2 · n H 2 O ( n ≈ 6–10) separate out at low temperatures. However, in the presence of light, these solutions rapidly photodecompose to form a mixture of chloric and hydrochloric acids. Photolysis of individual ClO 2 molecules result in the radicals ClO and ClOO, while at room temperature mostly chlorine, oxygen, and some ClO 3 and Cl 2 O 6 are produced. Cl 2 O 3

14647-445: The daylight portion of UARS' orbit. The second was used infrequently to verify the sensitivity of the first. The Solar Stellar Irradiance Comparison Experiment was designed to measure solar radiation. The instrument used a novel approach to calibration: instead of calibrating against an internal reference lamp, the instrument regularly took measurements of bright blue stars, which have theoretically very stable emissions over intervals on

14798-424: The deadly effect on insects, the yellow-green colour, and the smell similar to aqua regia . He called it " dephlogisticated muriatic acid air " since it is a gas (then called "airs") and it came from hydrochloric acid (then known as "muriatic acid"). He failed to establish chlorine as an element. Common chemical theory at that time held that an acid is a compound that contains oxygen (remnants of this survive in

14949-475: The decades-long length of the TSI record to date. A precise knowledge of the TSI and its variation over time is essential to understanding climate change. Recent findings indicate that instrinsic TSI variation has had a much larger role (up to 50%) in global warming during the industrial era than previously predicted by global circulation models (GCM's). The profound sociological and economic implications of understanding

15100-576: The delocalisation of the unpaired electron. It explodes above −40 °C as a liquid and under pressure as a gas and therefore must be made at low concentrations for wood-pulp bleaching and water treatment. It is usually prepared by reducing a chlorate as follows: Its production is thus intimately linked to the redox reactions of the chlorine oxoacids. It is a strong oxidising agent, reacting with sulfur , phosphorus , phosphorus halides, and potassium borohydride . It dissolves exothermically in water to form dark-green solutions that very slowly decompose in

15251-574: The development of commercial bleaches and disinfectants , and a reagent for many processes in the chemical industry. Chlorine is used in the manufacture of a wide range of consumer products, about two-thirds of them organic chemicals such as polyvinyl chloride (PVC), many intermediates for the production of plastics , and other end products which do not contain the element. As a common disinfectant, elemental chlorine and chlorine-generating compounds are used more directly in swimming pools to keep them sanitary . Elemental chlorine at high concentration

15402-461: The diagnosis and treatment of medical conditions in space. Usually, there is no physician on board the ISS and diagnosis of medical conditions is a challenge. It is anticipated that remotely guided ultrasound scans will have application on Earth in emergency and rural care situations where access to a trained physician is difficult. In August 2020, scientists reported that bacteria from Earth, particularly Deinococcus radiodurans bacteria, which

15553-405: The effects of long-term space exposure on the human body, including muscle atrophy , bone loss , and fluid shift. These data will be used to determine whether high duration human spaceflight and space colonisation are feasible. In 2006, data on bone loss and muscular atrophy suggested that there would be a significant risk of fractures and movement problems if astronauts landed on a planet after

15704-682: The evolution, development, growth and internal processes of plants and animals. In response to some of the data, NASA wants to investigate microgravity 's effects on the growth of three-dimensional, human-like tissues and the unusual protein crystals that can be formed in space. Investigating the physics of fluids in microgravity will provide better models of the behaviour of fluids. Because fluids can be almost completely combined in microgravity, physicists investigate fluids that do not mix well on Earth. Examining reactions that are slowed by low gravity and low temperatures will improve our understanding of superconductivity . The study of materials science

15855-409: The experiments conducted by medieval alchemists , which commonly involved the heating of chloride salts like ammonium chloride ( sal ammoniac ) and sodium chloride ( common salt ), producing various chemical substances containing chlorine such as hydrogen chloride , mercury(II) chloride (corrosive sublimate), and aqua regia . However, the nature of free chlorine gas as a separate substance

16006-431: The first crewed space flight around the Earth. By matching the orbit of the ISS to that of Vostok 1 as closely as possible, in terms of ground path and time of day, documentary filmmaker Christopher Riley and ESA astronaut Paolo Nespoli were able to film the view that Yuri Gagarin saw on his pioneering orbital space flight. This new footage was cut together with the original Vostok 1 mission audio recordings sourced from

16157-447: The first time, and demonstrated that what was then known as "solid chlorine" had a structure of chlorine hydrate (Cl 2 ·H 2 O). Chlorine gas was first used by French chemist Claude Berthollet to bleach textiles in 1785. Modern bleaches resulted from further work by Berthollet, who first produced sodium hypochlorite in 1789 in his laboratory in the town of Javel (now part of Paris , France), by passing chlorine gas through

16308-482: The first two. Chlorine has the electron configuration [Ne]3s 3p , with the seven electrons in the third and outermost shell acting as its valence electrons . Like all halogens, it is thus one electron short of a full octet, and is hence a strong oxidising agent, reacting with many elements in order to complete its outer shell. Corresponding to periodic trends , it is intermediate in electronegativity between fluorine and bromine (F: 3.98, Cl: 3.16, Br: 2.96, I: 2.66), and

16459-545: The free element muriaticum (and carbon dioxide). They did not succeed and published a report in which they considered the possibility that dephlogisticated muriatic acid air is an element, but were not convinced. In 1810, Sir Humphry Davy tried the same experiment again, and concluded that the substance was an element, and not a compound. He announced his results to the Royal Society on 15 November that year. At that time, he named this new element "chlorine", from

16610-609: The gaseous products were discarded, and hydrogen chloride may have been produced many times before it was discovered that it can be put to chemical use. One of the first such uses was the synthesis of mercury(II) chloride (corrosive sublimate), whose production from the heating of mercury either with alum and ammonium chloride or with vitriol and sodium chloride was first described in the De aluminibus et salibus ("On Alums and Salts", an eleventh- or twelfth century Arabic text falsely attributed to Abu Bakr al-Razi and translated into Latin in

16761-456: The heaviest elements beyond bismuth ); and having an electronegativity higher than chlorine's ( oxygen and fluorine ) so that the resultant binary compounds are formally not chlorides but rather oxides or fluorides of chlorine. Even though nitrogen in NCl 3 is bearing a negative charge, the compound is usually called nitrogen trichloride . Chlorination of metals with Cl 2 usually leads to

16912-455: The laboratory, hydrogen chloride gas may be made by drying the acid with concentrated sulfuric acid. Deuterium chloride, DCl, may be produced by reacting benzoyl chloride with heavy water (D 2 O). At room temperature, hydrogen chloride is a colourless gas, like all the hydrogen halides apart from hydrogen fluoride , since hydrogen cannot form strong hydrogen bonds to the larger electronegative chlorine atom; however, weak hydrogen bonding

17063-403: The line shapes and strengths to obtain information about temperature and atmospheric make-up. The instrument consists of two parts, the telescope and the interferometer which consists of an optical bench and support electronics. The telescope used a narrow field of view to prevent Doppler shift variation across the field of view from distorting the results. Input from the telescope is fed to

17214-563: The most reactive chemical compounds known, the list of elements it sets on fire is diverse, containing hydrogen , potassium , phosphorus , arsenic , antimony , sulfur , selenium , tellurium , bromine , iodine , and powdered molybdenum , tungsten , rhodium , iridium , and iron . It will also ignite water, along with many substances which in ordinary circumstances would be considered chemically inert such as asbestos , concrete, glass, and sand. When heated, it will even corrode noble metals as palladium , platinum , and gold , and even

17365-794: The multiple bonds on alkenes and alkynes as well, giving di- or tetrachloro compounds. However, due to the expense and reactivity of chlorine, organochlorine compounds are more commonly produced by using hydrogen chloride, or with chlorinating agents such as phosphorus pentachloride (PCl 5 ) or thionyl chloride (SOCl 2 ). The last is very convenient in the laboratory because all side products are gaseous and do not have to be distilled out. Many organochlorine compounds have been isolated from natural sources ranging from bacteria to humans. Chlorinated organic compounds are found in nearly every class of biomolecules including alkaloids , terpenes , amino acids , flavonoids , steroids , and fatty acids . Organochlorides, including dioxins , are produced in

17516-409: The neon and carbon dioxide evaporated, they kept the instrument cool for a planned 19 months. The final cryogens evaporated from the instrument on May 5, 1993, and the instrument warmed up, ending its useful life. The instrument looked sideways out of the UARS platform to allow the instrument to look through the stratosphere and the lower mesosphere . CLAES produced a 19-month global database showing

17667-471: The optics unit on a two-axis gimbal and a fixed electronics unit. The optics unit contains a telescope that collects solar energy as well as the gas detectors. The electronics unit handles data, motor control and power for the instrument. HRDI observed the emission and absorption lines of molecular oxygen above the limb of the Earth, uses the Doppler shift of the lines to determine horizontal winds and uses

17818-411: The orbit to 518 km x 381 km. They were followed by the passivation of the satellite's systems. On 26 October 2010, the International Space Station performed a debris-avoidance maneuver in response to a conjunction with UARS. On 7 September 2011, NASA announced the impending uncontrolled re-entry of UARS, and noted that there was a small potential risk to the public. By 23 September 2011,

17969-424: The order of the spacecraft's operational lifetime. The instrument's input slit was configurable for solar or stellar modes, to accommodate for the vast difference in target brightness. In addition to stars, SOLSTICE also took occasional measurements of targets of opportunity, including the moon and other objects in the solar system. The ACRIM2 instrument on the UARS satellite measured the total solar irradiance (TSI),

18120-458: The other carbon–halogen bonds, the C–Cl bond is a common functional group that forms part of core organic chemistry . Formally, compounds with this functional group may be considered organic derivatives of the chloride anion. Due to the difference of electronegativity between chlorine (3.16) and carbon (2.55), the carbon in a C–Cl bond is electron-deficient and thus electrophilic . Chlorination modifies

18271-605: The oxidation state of chlorine decreases. The strengths of the chlorine oxyacids increase very quickly as the oxidation state of chlorine increases due to the increasing delocalisation of charge over more and more oxygen atoms in their conjugate bases. Most of the chlorine oxoacids may be produced by exploiting these disproportionation reactions. Hypochlorous acid (HOCl) is highly reactive and quite unstable; its salts are mostly used for their bleaching and sterilising abilities. They are very strong oxidising agents, transferring an oxygen atom to most inorganic species. Chlorous acid (HOClO)

18422-406: The periodic table form binary chlorides. The exceptions are decidedly in the minority and stem in each case from one of three causes: extreme inertness and reluctance to participate in chemical reactions (the noble gases , with the exception of xenon in the highly unstable XeCl 2 and XeCl 4 ); extreme nuclear instability hampering chemical investigation before decay and transmutation (many of

18573-418: The physical properties of hydrocarbons in several ways: chlorocarbons are typically denser than water due to the higher atomic weight of chlorine versus hydrogen, and aliphatic organochlorides are alkylating agents because chloride is a leaving group . Alkanes and aryl alkanes may be chlorinated under free-radical conditions, with UV light. However, the extent of chlorination is difficult to control:

18724-429: The processor via a fiber optic cable. HRDI conducted scientific operations from November 1991 until April 2005. The WINDII instrument measured wind, temperature and emission rate from airglow and aurora . The instrument looked at Earth's limb from two different angles, 45 degrees and 135 degrees off the spacecraft's angle of motion. This allowed the instrument to read the same areas of the sky from two angles within

18875-536: The reaction is not regioselective and often results in a mixture of various isomers with different degrees of chlorination, though this may be permissible if the products are easily separated. Aryl chlorides may be prepared by the Friedel-Crafts halogenation , using chlorine and a Lewis acid catalyst. The haloform reaction , using chlorine and sodium hydroxide , is also able to generate alkyl halides from methyl ketones, and related compounds. Chlorine adds to

19026-400: The relative climate change contributions of natural and anthropogenic forcings makes it essential that the TSI database, a critical component of climate change research, be carefully sustained into the foreseeable future. The UARS/ACRIM2 experiment was an important part of providing the long term TSI database. UARS was decommissioned on 14 December 2005. The final perigee lowering burns lowered

19177-518: The relatively weak signature of trace gases from the background radiation in the atmosphere, CLAES had to have high resolution and sensitivity. To achieve this, the instrument combined a telescope with an infrared spectrometer. The whole instrument was cryogenically cooled to keep heat from the instrument from interfering with the readings. The cryogenics system consisted of an inner tank of solid neon at −257 °C (−430 °F) and an outer tank of solid carbon dioxide at −150 °C (−238 °F). As

19328-601: The rising costs or they would cancel the entire project outright. Simultaneously, the USSR was conducting planning for the Mir-2 space station, and had begun constructing modules for the new station by the mid-1980s. However the collapse of the Soviet Union required these plans to be greatly downscaled, and soon Mir-2 was in danger of never being launched at all. With both space station projects in jeopardy, American and Russian officials met and proposed they be combined. The ISS

19479-412: The routinely scheduled launches of resupply craft allows new hardware to be launched with relative ease. Crews fly expeditions of several months' duration, providing approximately 160 person-hours per week of labour with a crew of six. However, a considerable amount of crew time is taken up by station maintenance. Perhaps the most notable ISS experiment is the Alpha Magnetic Spectrometer (AMS), which

19630-420: The same launches and crew time. Research is conducted in a wide variety of fields, including astrobiology , astronomy , physical sciences , materials science , space weather , meteorology , and human research including space medicine and the life sciences . Scientists on Earth have timely access to the data and can suggest experimental modifications to the crew. If follow-on experiments are necessary,

19781-615: The second half of the twelfth century by Gerard of Cremona , 1144–1187). Another important development was the discovery by pseudo-Geber (in the De inventione veritatis , "On the Discovery of Truth", after c. 1300) that by adding ammonium chloride to nitric acid , a strong solvent capable of dissolving gold (i.e., aqua regia ) could be produced. Although aqua regia is an unstable mixture that continually gives off fumes containing free chlorine gas, this chlorine gas appears to have been ignored until c. 1630, when its nature as

19932-521: The space station. The ISS is expected to have additional modules (the Axiom Orbital Segment , for example) and will be in service until the end of 2030, after which it is planned to be de-orbited by a dedicated NASA spacecraft. As the space race drew to a close in the early 1970s, the US and USSR began to contemplate a variety of potential collaborations in outer space. This culminated in

20083-481: The spin magnitude being greater than 1/2 results in non-spherical nuclear charge distribution and thus resonance broadening as a result of a nonzero nuclear quadrupole moment and resultant quadrupolar relaxation. The other chlorine isotopes are all radioactive, with half-lives too short to occur in nature primordially . Of these, the most commonly used in the laboratory are Cl ( t 1/2 = 3.0×10  y) and Cl ( t 1/2 = 37.2 min), which may be produced from

20234-404: The station via its eight docking and berthing ports . The ISS maintains an orbit with an average altitude of 400 kilometres (250 mi) and circles the Earth in roughly 93 minutes, completing 15.5 orbits per day. The ISS programme combines two prior plans to construct crewed Earth-orbiting stations: Space Station Freedom planned by the United States, and the Mir-2 station, planned by

20385-531: The station with Ku band communications, additional attitude control needed for the additional mass of the USOS, and additional solar arrays. Over the next two years, the station continued to expand. A Soyuz-U rocket delivered the Pirs docking compartment . The Space Shuttles Discovery , Atlantis , and Endeavour delivered the American Destiny laboratory and Quest airlock , in addition to

20536-554: The station's main robot arm, the Canadarm2 , and several more segments of the Integrated Truss Structure. Tragedy struck in 2003 with the loss of the Space Shuttle Columbia , which grounded the rest of the Shuttle fleet, halting construction of the ISS. Assembly resumed in 2006 with the arrival of STS-115 with Atlantis , which delivered the station's second set of solar arrays. Several more truss segments and

20687-517: The station, which was released on YouTube. It was the first music video filmed in space. In November 2017, while participating in Expedition 52 / 53 on the ISS, Paolo Nespoli made two recordings of his spoken voice (one in English and the other in his native Italian), for use on Misplaced Pages articles. These were the first content made in space specifically for Misplaced Pages. In November 2021,

20838-472: The station. The first crew, Expedition 1 , arrived that November aboard Soyuz TM-31 . The ISS grew steadily over the following years, with modules delivered by both Russian rockets and the Space Shuttle. Expedition 1 arrived midway between the Space Shuttle flights of missions STS-92 and STS-97 . These two flights each added segments of the station's Integrated Truss Structure , which provided

20989-437: The sulfur oxides SO 2 and SO 3 to produce ClSO 2 F and ClOSO 2 F respectively. It will also react exothermically with compounds containing –OH and –NH groups, such as water: Chlorine trifluoride (ClF 3 ) is a volatile colourless molecular liquid which melts at −76.3 °C and boils at 11.8  °C. It may be formed by directly fluorinating gaseous chlorine or chlorine monofluoride at 200–300 °C. One of

21140-431: The sun. The observations are made both through vacuum and through occultations of the sun through the atmosphere. This allowed a comparison of the amount of UV light that reaches the earth and the amount absorbed by the upper atmosphere. Because of the energy of UV, instrument degradation is a major issue. To help with this problem, the instrument contained two identical spectrometers. One was used almost continuously during

21291-586: The thermally unstable FClO to the chemically unreactive perchloryl fluoride (FClO 3 ), the other three being FClO 2 , F 3 ClO, and F 3 ClO 2 . All five behave similarly to the chlorine fluorides, both structurally and chemically, and may act as Lewis acids or bases by gaining or losing fluoride ions respectively or as very strong oxidising and fluorinating agents. The chlorine oxides are well-studied in spite of their instability (all of them are endothermic compounds). They are important because they are produced when chlorofluorocarbons undergo photolysis in

21442-574: The total solar radiant energy reaching Earth, continuing the climate change database begun in 1980 by the ACRIM1 experiment on the Solar Maximum Mission (SMM). The ACRIM1 experiment's results provided the first discoveries of intrinsic variations in the TSI and their relationships to solar magnetic activity phenomena. ACRIM experiments have confirmed TSI variation occurs on virtually every timescale from their 2-minute observation cadence to

21593-852: The universe. Examples of Earth-viewing remote sensing experiments that have flown on the ISS are the Orbiting Carbon Observatory 3 , ISS-RapidScat , ECOSTRESS , the Global Ecosystem Dynamics Investigation , and the Cloud Aerosol Transport System . ISS-based astronomy telescopes and experiments include SOLAR , the Neutron Star Interior Composition Explorer , the Calorimetric Electron Telescope ,

21744-406: The upper atmosphere and cause the destruction of the ozone layer. None of them can be made from directly reacting the elements. Dichlorine monoxide (Cl 2 O) is a brownish-yellow gas (red-brown when solid or liquid) which may be obtained by reacting chlorine gas with yellow mercury(II) oxide . It is very soluble in water, in which it is in equilibrium with hypochlorous acid (HOCl), of which it

21895-802: The vertical distributions of important ozone-layer gases in the stratosphere and their variation with time of day, season, latitude, and longitude. ISAMS is an infrared radiometer for measuring thermal emission from the Earth's limb (the line of the horizon as seen from UARS), on both sides of the spacecraft. It used the pressure-modulation technique to obtain high spectral resolution, and innovative stirling-cycle coolers to achieve high detector sensitivity. ISAMS uses 7 gas cells for 6 different gases: CO 2 (times 2), CO, CH 4 , N 2 O, NO 2 and H 2 O. The CO 2 cells also allow measurement of ozone (O 3 ), nitric acid (HNO 3 ) and dinitrogen pentoxide (N 2 O 5 ) The specific objectives of ISAMS were: (i) To obtain measurements of atmospheric temperature as

22046-569: Was first used as a weapon on April 22, 1915, at the Second Battle of Ypres by the German Army . The effect on the allies was devastating because the existing gas masks were difficult to deploy and had not been broadly distributed. Chlorine is the second halogen , being a nonmetal in group 17 of the periodic table. Its properties are thus similar to fluorine , bromine , and iodine , and are largely intermediate between those of

22197-511: Was only recognised around 1630 by Jan Baptist van Helmont . Carl Wilhelm Scheele wrote a description of chlorine gas in 1774, supposing it to be an oxide of a new element. In 1809, chemists suggested that the gas might be a pure element, and this was confirmed by Sir Humphry Davy in 1810, who named it after the Ancient Greek χλωρός ( khlōrós , "pale green") because of its colour. Because of its great reactivity, all chlorine in

22348-401: Was originally intended to be a laboratory, observatory, and factory while providing transportation, maintenance, and a low Earth orbit staging base for possible future missions to the Moon, Mars, and asteroids. However, not all of the uses envisioned in the initial memorandum of understanding between NASA and Roscosmos have been realised. In the 2010 United States National Space Policy ,

22499-550: Was the Skylab-Salyut Space Laboratory, which proposed docking the Skylab B to a Soviet Salyut space station. Falling budgets and rising Cold War tensions in the late 1970s saw these concepts fall by the wayside, along with another plan to have the Space Shuttle dock with a Salyut space station. In the early 1980s, NASA planned to launch a modular space station called Freedom as a counterpart to

22650-628: Was used as early as 3000 BC and brine as early as 6000 BC. Around 900, the authors of the Arabic writings attributed to Jabir ibn Hayyan (Latin: Geber) and the Persian physician and alchemist Abu Bakr al-Razi ( c. 865–925, Latin: Rhazes) were experimenting with sal ammoniac ( ammonium chloride ), which when it was distilled together with vitriol (hydrated sulfates of various metals) produced hydrogen chloride . However, it appears that in these early experiments with chloride salts ,

22801-434: Was used in experimental rocket engine, but has problems largely stemming from its extreme hypergolicity resulting in ignition without any measurable delay. Today, it is mostly used in nuclear fuel processing, to oxidise uranium to uranium hexafluoride for its enriching and to separate it from plutonium , as well as in the semiconductor industry, where it is used to clean chemical vapor deposition chambers. It can act as

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