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30-399: Polyus may refer to: Polyus (spacecraft) , a Soviet spacecraft launched in 1987 that failed to reach orbit Polyus (company) , a Russian gold producer Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Polyus . If an internal link led you here, you may wish to change

60-490: A ballistic trajectory . Carbon dioxide laser The carbon-dioxide laser ( CO 2 laser ) was one of the earliest gas lasers to be developed. It was invented by Kumar Patel of Bell Labs in 1964 and is still one of the most useful types of laser. Carbon-dioxide lasers are the highest-power continuous-wave lasers that are currently available. They are also quite efficient: the ratio of output power to pump power can be as large as 20%. The CO 2 laser produces

90-417: A beam of infrared light with the principal wavelength bands centering on 9.6 and 10.6  micrometers (μm). The active laser medium (laser gain/ amplification medium) is a gas discharge which is air- or water-cooled, depending on the power being applied. The filling gas within a sealed discharge tube consists of around 10–20% carbon dioxide ( CO 2 ), around 10–20% nitrogen ( N 2 ),

120-456: A few hundred micrometers. Because the atmosphere is quite transparent to infrared light, CO 2 lasers are also used for military rangefinding using LIDAR techniques. CO 2 lasers are used in spectroscopy and the Silex process to enrich uranium. In semiconductor manufacturing, CO 2 lasers are used for extreme ultraviolet generation. The Soviet Polyus was designed to use

150-454: A few percent hydrogen ( H 2 ) and/or xenon (Xe), with the remainder being helium (He). A different mixture is used in a flow-through laser, where CO 2 is continuously pumped through it. The specific proportions vary according to the particular laser. The population inversion in the laser is achieved by the following sequence: electron impact excites the {v1(1)} quantum vibrational modes of nitrogen. Because nitrogen

180-523: A weapon in space and that such an attempt would contradict the country's previous statements on the USSR's peaceful intent. For technical reasons, the payload was launched upside down. It was designed to separate from the Energia, rotate 180 degrees in yaw, then 90 degrees in roll and then fire its engine to complete its boost to orbit. The Energia functioned perfectly, however, after separation from Energia,

210-411: Is a homonuclear molecule , it cannot lose this energy by photon emission, and its excited vibrational modes are therefore metastable and relatively long-lived. N 2 {v1(1)} and CO 2 {v3(1)} being nearly perfectly resonant (total molecular energy differential is within 3 cm when accounting for N 2 anharmonicity, centrifugal distortion and vibro-rotational interaction, which

240-782: Is affected by the particular isotopes contained in the carbon dioxide molecule, with heavier isotopes causing longer wavelength emission. Because of the high power levels available (combined with reasonable cost for the laser), CO 2 lasers are frequently used in industrial applications for cutting and welding , while lower power level lasers are used for engraving. In selective laser sintering , CO 2 lasers are used to fuse particles of plastic powder into parts. Carbon-dioxide lasers have become useful in surgical procedures because water (which makes up most biological tissue ) absorbs this frequency of light very well. Some examples of medical uses are laser surgery and skin resurfacing ("laser facelifts ", which essentially consist of vaporizing

270-474: Is also very easy to actively Q-switch a CO 2 laser by means of a rotating mirror or an electro-optic switch, giving rise to Q-switched peak powers of up to gigawatts (GW). Because the laser transitions are actually on vibration-rotation bands of a linear triatomic molecule, the rotational structure of the P and R bands can be selected by a tuning element in the laser cavity . Prisms are not practical as tuning elements because most media that transmit in

300-566: Is more than made up for by the Maxwell speed distribution of translational-mode energy), N 2 collisionally de-excites by transferring its vibrational mode energy to the CO 2 molecule, causing the carbon dioxide to excite to its {v3(1)} (asymmetric stretch) vibrational mode quantum state. The CO 2 then radiatively emits at either 10.6 μm by dropping to the {v1(1)} (symmetric-stretch) vibrational mode, or 9.6 μm by dropping to

330-453: The Energia , capable of launching about 95 tonnes into orbit, finally allowed the spacecraft to accommodate the massive laser. The massive exhaust of the carbon-dioxide laser precipitated the objective of making the laser "recoil-less". The zero-torque exhaust system (SBM) was developed to that end. Its testing in orbit meant the release of a large cloud of carbon dioxide, which would hint at

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360-528: The ISS modules Zarya and Nauka . NPO Energia received orders from the Soviet government to begin research on space-based strike weapons in the mid-1970s. Even before, the USSR had been developing maneuverable satellites for the purpose of satellite interception. By the beginning of the 1980s, Energia had proposed two programs: laser-equipped Skif and guided missiles platform Kaskad (where Skif would cover

390-653: The mid-infrared absorb or scatter some of the light, so the frequency tuning element is almost always a diffraction grating . By rotating the diffraction grating, a particular rotational line of the vibrational transition can be selected. The finest frequency selection may also be obtained through the use of an etalon . In practice, together with isotopic substitution , this means that a continuous comb of frequencies separated by around 1 cm (30 GHz) can be used that extend from 880 to 1090 cm . Such "line-tuneable" carbon-dioxide lasers are principally of interest in research applications. The laser's output wavelength

420-427: The 9.25–9.6 μm wavelength is sometimes used in dentistry for hard-tissue ablation. The hard-tissue is ablated at temperatures as high as 5,000 °C, producing bright thermal radiation. The common plastic poly (methyl methacrylate) (PMMA) absorbs IR light in the 2.8–25 μm wavelength band, so CO 2 lasers have been used in recent years for fabricating microfluidic devices from it, with channel widths of

450-546: The Polyus spun a full 360 degrees instead of the planned 180 degrees. When the engine fired, it slowed the vehicle, which burned up over the south Pacific Ocean. This failure was attributed to a faulty inertial guidance system that had not been rigorously tested due to the rushed production schedule. Parts of the Polyus project's hardware were re-used in Kvant-2 , Kristall , Spektr and Priroda Mir modules, as well as in

480-464: The almost-completed Skif spacecraft would be launched instead for a 30-day mission. The development of the real Skif was completed in just one year, from September 1985 to September 1986. Testing and tweaking the Energia launch vehicle, the launch pad and the Skif itself moved the launch to February, and later to May 1987. According to Boris Gubanov, the head designer of the Energia launch vehicle,

510-709: The best surgical laser for the soft tissue where both cutting and hemostasis are achieved photo-thermally (radiantly). CO 2 lasers can be used in place of a scalpel for most procedures and are even used in places a scalpel would not be used, in delicate areas where mechanical trauma could damage the surgical site. CO 2 lasers are the best suited for soft-tissue procedures in human and animal specialties, as compared to laser with other wavelengths . Advantages include less bleeding, shorter surgery time, less risk of infection, and less post-op swelling. Applications include gynecology , dentistry , oral and maxillofacial surgery , and many others. A CO 2 dental laser at

540-588: The excitation energy of molecular vibrational and rotational mode quantum states are low, the photons emitted due to transition between these quantum states have comparatively lower energy, and longer wavelength, than visible and near-infrared light. The 9–12 μm wavelength of CO 2 lasers is useful because it falls into an important window for atmospheric transmission (up to 80% atmospheric transmission at this wavelength), and because many natural and synthetic materials have strong characteristic absorption in this range. The laser wavelength can be tuned by altering

570-572: The first flight of the Energia system, but failed to reach orbit. According to Yuri Kornilov, Chief Designer of the Salyut Design Bureau, shortly before Polyus' launch, Mikhail Gorbachev visited the Baikonur Cosmodrome and expressly forbade the in-orbit testing of its capabilities. Kornilov claims that Gorbachev was worried that it would be possible for Western governments to view this activity as an attempt to create

600-531: The helium atoms strike the walls of the laser discharge tube. In flow-through lasers, a continuous stream of CO 2 and nitrogen is excited by the plasma discharge and the hot gas mixture is exhausted from the resonator by pumps. The addition of helium also plays a role in the initial vibrational excitation of N 2 , due to a near-resonant dissociation reaction with metastable He(2 S 1 ). Substituting helium with other noble gases, such as neon or argon, does not lead to an enhancement of laser output. Because

630-904: The isotopic ratio of the carbon and oxygen atoms comprising the CO 2 molecules in the discharge tube. Because CO 2 lasers operate in the infrared, special materials are necessary for their construction. Typically, the mirrors are silvered , while windows and lenses are made of either germanium or zinc selenide . For high power applications, gold mirrors and zinc selenide windows and lenses are preferred. There are also diamond windows and lenses in use. Diamond windows are extremely expensive, but their high thermal conductivity and hardness make them useful in high-power applications and in dirty environments. Optical elements made of diamond can even be sand blasted without losing their optical properties. Historically, lenses and windows were made out of salt (either sodium chloride or potassium chloride ). While

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660-460: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Polyus&oldid=946552936 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Polyus (spacecraft) The Polyus spacecraft was launched 15 May 1987 from Baikonur Cosmodrome Site 250 as part of

690-581: The low-orbit targets, Kaskad engaged targets in high and geosynchronous orbits). Together with NPO Astrofizika and KB Salyut , they began developing their orbital weapons platform based on the Salyut DOS-17K frame. Later, when the objective of ICBM interception proved too difficult, the aims of the project were shifted towards anti-satellite weapons. The 1983 announcement by the US of their SDI program prompted further political and financial support for

720-471: The material was inexpensive, the lenses and windows degraded slowly with exposure to atmospheric moisture. The most basic form of a CO 2 laser consists of a gas discharge (with a mix close to that specified above) with a total reflector at one end, and an output coupler (a partially reflecting mirror) at the output end. The CO 2 laser can be constructed to have continuous wave (CW) powers between milliwatts (mW) and hundreds of kilowatts (kW). It

750-507: The satellite interceptor program. In the nuclear exchange scenario, the interceptors would destroy the SDI satellites, followed by a so-called "pre-emptive retaliation" large-scale Soviet ICBM launch. The laser chosen for the Skif spacecraft was a 1-megawatt carbon dioxide laser , developed for the Beriev A-60 aircraft (an Il-76 flying laboratory with a combat laser). The introduction of

780-456: The satellite's purpose. Instead, the xenon-krypton mix would be used to simultaneously test the SBM and perform an innocent experiment on Earth's ionosphere . In 1985, the decision was made to test-launch the new Energia launch vehicle, which was still in the testbed phase. A 100-ton dummy payload was initially considered for the launch, but in a series of last-minute changes, it was decided that

810-485: The skin to promote collagen formation). CO 2 lasers may be used to treat certain skin conditions such as hirsuties papillaris genitalis by removing bumps or podules. CO 2 lasers can be used to remove vocal-fold lesions, such as vocal-fold cysts . Researchers in Israel are experimenting with using CO 2 lasers to weld human tissue, as an alternative to traditional sutures . The 10.6 μm CO 2 laser remains

840-463: The timing control device gave the logical block a command to discard the side modules' covers and laser exhaust covers. Unknowingly, the same command was earlier used to open the solar panels and disengage the maneuvering thrusters. This was not discovered because of the logistics of the testing process and overall haste. Main thrusters engaged while the Skif kept turning, overshooting the intended 180-degree turn. The spacecraft lost speed and reverted to

870-452: The work schedule of the preceding years was exhausting, and at the point of Mikhail Gorbachev's visit on 11 May, he asked the Soviet premier to clear the launch now, because "there will be heart attacks". The catastrophic malfunction that led to Skif entering the atmosphere in the same area as Energia's second stage was successfully investigated. It was found that 568 seconds after launch,

900-417: The {v20(2)} (bending) vibrational mode. The carbon dioxide molecules then transition to their {v20(0)} vibrational mode ground state from {v1(1)} or {v20(2)} by collision with cold helium atoms, thus maintaining population inversion. The resulting hot helium atoms must be cooled in order to sustain the ability to produce a population inversion in the carbon dioxide molecules. In sealed lasers, this takes place as

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