Menus were prepared by the cosmonauts, with the help of a dietitian, before their flight to the station. The diet was designed to provide around 100 g of protein, 130 g of fat and 330 g of carbohydrates per day, in addition to appropriate mineral and vitamin supplements. Meals were spread out throughout the day to aid assimilation. Canned food such as jellied beef tongue was placed into one of several niches in the core module's table, where they could be warmed in 5–10 minutes. Usually, crews drank tea, coffee and fruit juices, but, unlike the ISS, the station also had a supply of cognac and vodka for special occasions. Station operations Expeditions During its 15-year spaceflight, Mir was visited by a total of 28 long-duration or "principal" crews, each of which was given a sequential expedition number formatted as EO-X. Expeditions varied in length (from the 72-day flight of the crew of EO-28 to the 437-day flight of Valeri Polyakov), but generally lasted around six months. Principal expedition crews consisted of two to three crew members, who often launched as part of one expedition but returned with another (Polyakov launched with EO-14 and landed with EO-17). The principal expeditions were often supplemented with visiting crews who remained on the station during the week-long handover period between one crew and the next before returning with the departing crew, the station's life support system being able to support a crew of up to six for short periods. The station was occupied for a total of four distinct periods; 12 March–16 July 1986 (EO-1), 5 February 1987 – 27 April 1989 (EO-2–EO-4), the record-breaking run from 5 September 1989 – 28 August 1999 (EO-5–EO-27), and 4 April–16 June 2000 (EO-28). By the time of the station's deorbit, it had been visited by 104 different people from twelve different nations, making it the second-most visited spacecraft in history after the International Space Station. Early existence Due to the pressure to launch the station in such short order, mission planners were left without Soyuz spacecraft or modules to launch to the station at first. It was decided to launch Soyuz T-15 on a dual mission to both Mir and Salyut 7. Leonid Kizim and Vladimir Solovyov first docked with the Mir space station on 15 March 1986. During their nearly 51-day stay on Mir, they brought the station online and checked its systems. They also unloaded two Progress spacecraft launched after their arrival, Progress 25 and Progress 26. On 5 May 1986, they undocked from Mir for a day-long journey to Salyut 7. They spent 51 days there and gathered 400 kg of scientific material from Salyut 7 for return to Mir. While Soyuz T-15 was at Salyut 7, the unmanned Soyuz TM-1 arrived at the unoccupied Mir and remained for 9 days, testing the new Soyuz TM model. Soyuz T-15 redocked with Mir on 26 June and delivered the experiments and 20 instruments, including a multichannel spectrometer. The EO-1 crew spent their last 20 days on Mir conducting Earth observations before returning to Earth on 16 July 1986, leaving the new station unoccupied. The second expedition to Mir, EO-2, launched on Soyuz TM-2 on 5 February 1987. During their stay, the Kvant-1 module, launched on 30 March 1987, arrived. It was the first experimental version of a planned series of '37K' modules scheduled to be launched to Mir on the Soviet Buran spacecraft. Kvant-1 was originally planned to dock with Salyut 7; however, due to technical problems during its development, it was reassigned to Mir. The module carried the first set of six gyroscopes for attitude control. The module also carried instruments for X-ray and ultraviolet astrophysical observations. The initial rendezvous of the Kvant-1 module with Mir on 5 April 1987 was troubled by the failure of the onboard control system. After the failure of the second attempt to dock, the resident cosmonauts, Yuri Romanenko and Aleksandr Laveykin, conducted an EVA to fix the problem. They found a trash bag which had been left in orbit after the departure of one of the previous cargo ships and was now located between the module and the station, which prevented the docking. After removing the bag docking could be completed on 12 April. The Soyuz TM-2 launch was the beginning of a string of 6 Soyuz launches and three long-duration crews between 5 February 1987 and 27 April 1989. This period also saw the first international visitors to the station, Muhammed Faris (Syria), Abdul Ahad Mohmand (Afghanistan) and Jean-Loup Chrétien (France). With the departure of EO-4 on Soyuz TM-7 on 27 April 1989 the station was once again left unoccupied. တတိယအဆင့် The launch of Soyuz TM-8 on 5 September 1989 marked the beginning of the longest human presence in space up until 23 October 2010 (when this record was surpassed by the ISS). It also marked the beginning of Mir's second expansion. The Kvant-2 and Kristall modules were now ready for launch. Alexander Viktorenko and Aleksandr Serebrov docked with Mir and brought the station out of its five-month hibernation. On 29 September the cosmonauts installed equipment in the docking system in preparation for the arrival of Kvant-2, the first of the 20 tonne add-on modules based on the TKS spacecraft from the Almaz programme. alt=A collection of three space station modules, arranged in an L-shape. At the left of the image is a Soyuz spacecraft docked to a short, stubby module, in turn docked to a larger, stepped-cylindrical module covered in white insulation, from which solar arrays project. A third module, similar in size to the stepped-cylinder module, is attached to the upper port of that module, forming the up-stroke of the L. This module is also projecting two solar arrays, and the cloudy Earth serves as the image's backdrop. After a delay of 40 days due to problems with a batch of computer chips, Kvant-2 was launched on 26 November 1989. After problems deploying the craft's solar array and with the automated docking systems on both Kvant-2 and Mir, the new module was docked manually on 6 December. Kvant-2 added a second set of gyrodines to Mir, and also carried the new life support systems for recycling water and generating oxygen on board the station, reducing its dependence on resupply from the ground. The module also featured a large airlock with a one-metre hatch. A special backpack unit (known as Ikar), an equivalent of the U.S. MMU, was located inside Kvant-2's airlock. Soyuz TM-9 launched EO-6 crew members Anatoly Solovyev and Aleksandr Balandin on 11 February 1990. While docking, the EO-5 crew on board Mir noted that three thermal blankets on the ferry were loose, potentially creating problems on reentry, but it was decided that they would be manageable. Their stay on board Mir saw the addition of the Kristall module, launched on 31 May 1990. The first docking attempt on 6 June was aborted due to an attitude control thruster failure. Kristall arrived at Mir’s front port on 10 June and was relocated to the lateral port opposite Kvant-2 the next day, restoring the equilibrium of the complex. Due to the delay in the docking of Kristall, EO-6 was extended by 10 days to permit the activation of the module’s systems and to accommodate the EVA to repair the loose thermal blankets on Soyuz TM-9.Kristall contained a number of furnaces for use in producing crystals under microgravity conditions (hence the choice of name for the module). The module was also equipped with biotechnology research equipment, including a small greenhouse for plant cultivation experiments which was equipped with a source of light and a feeding system, in addition to equipment for astronomical observations. The most obvious features of the module, however, were the two Androgynous Peripheral Attach System (APAS-89) docking ports designed to be compatible with the Buran spacecraft. Although they were never used in a Buran docking, they were later to prove very useful during the Shuttle-Mir programme, providing a berthing location for U.S Space Shuttles. The EO-7 relief crew arrived aboard Soyuz TM-10 on 3 August 1990. The new crew arrived at Mir with quail for Kvant-2's cages, one of which laid an egg en route to the station. It was returned to Earth, along with 130 kg of experiment results and industrial products, in Soyuz TM-9. Two more expeditions, EO-8 and EO-9, continued the work of their predecessors whilst tensions grew back on Earth. ဆိုဗီယက်ခေတ်လွန်ကာလ alt=An image of a space station consisting of four modules arranged in a T-shape. A short, stubby module is docked to a longer, stepped-cylindrical module which has a number of docking ports arranged in a sphere at one end. Two other modules, similar in size, project from opposing ports on this sphere. A Progress spacecraft is docked to the short module, a Soyuz spacecraft to the end of the lower module in the crossbar of the T, and another Progress spacecraft is seen a distance away from the module cluster, carrying out undocking operations. The EO-10 crew, launched aboard Soyuz TM-13 on 2 October 1991, was the last crew to launch from the USSR and continued the occupation of Mir through the fall of the Soviet Union. The crew is notable for having launched as Soviet citizens and returning to earth as Russians. The newly formed Russian Federal Space Agency (Roskosmos) was unable to finance the unlaunched Spektr and Priroda modules, instead putting them into storage and ending Mir's second expansion. The first manned mission flown from an independent Kazakhstan was Soyuz TM-14, launched on 17 March 1992, which carried the EO-11 crew to Mir, docking on 19 March before the departure of Soyuz TM-13. On 17 June, Russian President Boris Yeltsin and U.S. President George H. W. Bush announced what would later become the Shuttle-Mir programme, a cooperative venture which would prove very useful to the cash-strapped Roskosmos (and led to the eventual completion and launch of Spektr and Priroda). EO-12 followed in July, alongside a brief visit by French astronaut Michel Tognini. The crew which succeeded them, EO-13, began preparations for the Shuttle-Mir programme by flying to the station in a modified spacecraft, Soyuz TM-16 (launched on 26 January 1993), which was equipped with an APAS-89 docking system rather than the usual probe-and-drogue, enabling it to dock to Kristall and test the port which would later be used by U.S. space shuttles. The spacecraft also enabled controllers to obtain data on the dynamics of docking a spacecraft to a space station off the station's longitudinal axis, in addition to data on the structural integrity of this configuration via a test called Rezonans conducted on 28 January. Soyuz TM-15, meanwhile, departed with the EO-12 crew on 1 February. Throughout the period following the collapse of the USSR, crews on Mir experienced occasional reminders of the economic chaos occurring in Russia. The initial cancellation of Spektr and Priroda was the first such sign, closely followed by the reduction in communications as a result of the fleet of tracking ships being withdrawn from service by Ukraine. The new Ukrainian government also vastly raised the price of the Kurs docking systems, manufactured in Kievthe Russians' attempts to reduce their dependence on Kurs would later lead to accidents during TORU tests in 1997. Various Progress spacecraft had parts of their cargoes missing, either because the consumable in question had been unavailable, or because the ground crews at Baikonur had, in desperation, looted them. The problems became particularly obvious during the launch of the EO-14 crew aboard Soyuz TM-17 in July; half an hour before launch there was a black-out at the pad, and the entire power supply to the nearby city of Leninsk failed an hour after launch. Nevertheless, the spacecraft launched on time and arrived at the station two days later. All of Mir's ports, however, were occupied, and so Soyuz TM-17 had to station-keep 200 metres away from the station for half an hour before docking whilst Progress M-18 vacated the core module's front port and departed. The EO-13 crew departed on 22 July, and soon after Mir passed through the annual Perseid meteor shower, during which the station was hit by several particles. A spacewalk was conducted on 28 September to inspect the station's hull, but no serious damage was reported. Soyuz TM-18 arrived on 10 January 1994 carrying the EO-15 crew (including Valeri Polyakov, who was to remain on Mir for 14 months), and Soyuz TM-17 left on 14 January. The undocking was unusual, however, in that the spacecraft was to pass along Kristall in order to obtain photographs of the APAS to assist in the training of space shuttle pilots. Due to an error in setting up the control system, the spacecraft struck the station a glancing blow during the manoeuvre, scratching the exterior of Kristall. The launch of Soyuz TM-19, carrying the EO-16 crew, was delayed due to the unavailability of a payload fairing for the booster that was to carry it, but the spacecraft eventually left Earth on 1 July 1994 and docked two days later. They stayed only four months to allow the Soyuz schedule to line up with the planned space shuttle manifest, and so Polyakov greeted a second resident crew in October, prior to the undocking of Soyuz TM-19, when the EO-17 crew arrived in Soyuz TM-20. A few months later, Mir veteran Vladimir Titov became the first Russian cosmonaut to launch on a U.S. spacecraft flying on during STS-63. Shuttle–Mir alt=A cluster of cylindrical modules with projecting feathery solar arrays and a space shuttle docked to the lower module. In the background is the blackness of space, and, in the lower right corner, Earth. The 3 February launch of , flying STS-63, opened operations on Mir for 1995. Referred to as the "near-Mir" mission, the mission saw the first rendezvous of a space shuttle with Mir as the orbiter approached within of the station as a dress rehearsal for later docking missions and for equipment testing. Five weeks after Discoverys departure, the EO-18 crew, including the first U.S. cosmonaut Norman Thagard, arrived in Soyuz TM-21. The EO-17 crew left a few days later, with Polyakov completing his record-breaking 437-day spaceflight. During EO-18, the Spektr science module (which served as living and working space for American astronauts) was launched aboard a Proton rocket and docked to the station, carrying research equipment from America and other nations. The expedition's crew returned to Earth aboard following the first Shuttle–Mir docking mission, STS-71. Atlantis, launched on 27 June 1995, successfully docked with Mir on 29 June becoming the first U.S. spacecraft to dock with a Russian spacecraft since the ASTP in 1975. The orbiter delivered the EO-19 crew and returned the EO-18 crew to Earth. The EO-20 crew were launched on 3 September, followed in November by the arrival of the docking module during STS-74. The two-man EO-21 crew was launched on 21 February 1996 aboard Soyuz TM-23 and were soon joined by U.S. crew member Shannon Lucid, who was brought to the station by Atlantis during STS-76. This mission saw the first joint U.S. spacewalk on Mir take place deploying the MEEP package on the docking module. Lucid became the first American to carry out a long-duration mission aboard Mir with her 188-day mission, which set the U.S. single spaceflight record. During Lucid's time aboard Mir, Priroda, the station's final module, arrived as did French visitor Claudie Haigneré flying the Cassiopée mission. The flight aboard Soyuz TM-24 also delivered the EO-22 crew of Valery Korzun and Aleksandr Kaleri. Lucid's stay aboard Mir ended with the flight of Atlantis on STS-79, which launched on 16 September. This, the fourth docking, saw John Blaha transferring onto Mir to take his place as resident U.S. astronaut. His stay on the station improved operations in several areas, including transfer procedures for a docked space shuttle, "hand-over" procedures for long duration American crew members and "ham" amateur radio communications, and also saw two spacewalks to reconfigure the station's power grid. In all, Blaha spent four months with the EO-22 crew before returning to Earth aboard Atlantis on STS-81 in January 1997, at which point he was replaced by physician Jerry Linenger. During his flight, Linenger became the first American to conduct a spacewalk from a foreign space station and the first to test the Russian-built Orlan-M spacesuit alongside Russian cosmonaut Vasili Tsibliyev, flying EO-23. All three crew members of EO-23 performed a "fly-around" in Soyuz TM-25 spacecraft. Linenger and his Russian crewmates Vasili Tsibliyev and Aleksandr Lazutkin faced several difficulties during the mission, including the most severe fire aboard an orbiting spacecraft (caused by a malfunctioning Vika), failures of various on board systems, a near collision with Progress M-33 during a long-distance TORU test and a total loss of station electrical power. The power failure also caused a loss of attitude control, which led to an uncontrolled "tumble" through space. Linenger was succeeded by Anglo-American astronaut Michael Foale, carried up by Atlantis on STS-84, alongside Russian mission specialist Elena Kondakova. Foale's increment proceeded fairly normally until 25 June when during the second test of the Progress manual docking system, TORU, Progress M-34 collided with solar arrays on the Spektr module and crashed into the module's outer shell, puncturing the module and causing depressurisation on the station. Only quick actions on the part of the crew, cutting cables leading to the module and closing Spektr's hatch, prevented the crews having to abandon the station in Soyuz TM-25. Their efforts stabilised the station's air pressure, whilst the pressure in Spektr, containing many of Foale's experiments and personal effects, dropped to a vacuum. In an effort to restore some of the power and systems lost following the isolation of Spektr and to attempt to locate the leak, EO-24 commander Anatoly Solovyev and flight engineer Pavel Vinogradov carried out a risky salvage operation later in the flight, entering the empty module during a so-called "intra-vehicular activity" or "IVA" spacewalk and inspecting the condition of hardware and running cables through a special hatch from Spektr's systems to the rest of the station. Following these first investigations, Foale and Solovyev conducted a 6-hour EVA on the surface of Spektr to inspect the damage to the punctured module. After these incidents, the U.S. Congress and NASA considered whether to abandon the programme out of concern for the astronauts' safety, but NASA administrator Daniel Goldin decided to continue the programme. The next flight to Mir, STS-86, brought David Wolf to the station aboard Atlantis. During the orbiter's stay Titov and Parazynski conducted a spacewalk to affix a cap to the docking module for a future attempt by crew members to seal off the leak in Spektr's hull. Wolf spent 119 days aboard Mir with the EO-24 crew and was replaced during STS-89 with Andy Thomas, who carried out the last U.S. expedition on Mir. The EO-25 crew arrived in Soyuz TM-27 in January 1998 before Thomas returned to Earth on the final Shuttle–Mir mission, STS-91. Final days and deorbit alt=A view of a bluish-grey sky through which four large and eight smaller points of light are descending in a top-right to bottom-left direction, trailing smoke. Following the departure of Discovery on 8 June 1998, the EO-25 crew of Budarin and Musabayev were left aboard the station, carrying out materials experiments and the compiling of a station inventory. Meanwhile, back on Earth, Yuri Koptev, the director of the Roskosmos, announced on 2 July that, due to a lack of funding to keep Mir flying, the station would be deorbited in June 1999. The EO-26 crew of Gennady Padalka and Sergei Avdeyev arrived on 15 August in Soyuz TM-28, alongside physicist Yuri Baturin, who departed with the EO-25 crew on 25 August in Soyuz TM-27. The crew carried out two spacewalks, one inside Spektr to reseat some power cables and another outside to set up experiments delivered by Progress M-40, which also carried a large amount of propellant to begin alterations to Mir's orbit ready for the station's decommissioning. 20 November 1998 saw the launch of Zarya, the first module of the International Space Station, but delays to the new station's service module Zvezda had led to calls for Mir to be kept in orbit past 1999. Roskosmos, however, confirmed that it would not fund Mir past the set deorbit date. The crew of EO-27, consisting of Viktor Afanasyev and Jean-Pierre Haigneré arrived in Soyuz TM-29 on 22 February 1999 alongside Ivan Bella, who returned to Earth with Padalka in Soyuz TM-28. The crew carried out three EVAs to retrieve experiments and deploy a prototype communications antenna on Sofora. Meanwhile, on 1 June it was announced that the deorbit of the station would be delayed by six months to allow time to seek alternative funding to keep the station operating. The rest of the expedition was spent preparing the station for its deorbit; a special analogue computer was installed and each of the modules, starting with the docking module, was mothballed in turn and sealed off. The crew loaded their results into Soyuz TM-29 and departed Mir on 28 August 1999, ending a run of continuous occupation of the station which had lasted for eight days short of ten years. The station's gyrodynes and main computer were shut down on 7 September, leaving Progress M-42 to control Mir and refine the station's orbital decay rate. Near the end of its life, there were plans for private interests to purchase Mir, possibly for use as the first orbital television/movie studio. The privately funded Soyuz TM-30 mission by MirCorp, launched on 4 April 2000, carried two crew members, Sergei Zalyotin and Aleksandr Kaleri, to the station for two months to do repair work with the hope of proving that the station could be made safe. This was, however, to be the last manned mission to Mir - while Russia was optimistic about Mirs future, its commitments to the International Space Station project left no funding to support the aging station. Mir's deorbit was carried out in three stages. The first stage involved waiting for atmospheric drag to reduce the station's orbit to an average of . This began with the docking of Progress M1-5, a modified version of the Progress-M carrying 2.5 times more fuel in place of supplies. The second stage was the transfer of the station into a 165 × 220 km (103 × 137 mi) orbit. This was achieved with two burns of Progress M1-5's control engines at 00:32 UTC and 02:01 UTC on 23 March 2001. After a two-orbit pause, the third and final stage of Mir's deorbit began with the burn of Progress M1-5's control engines and main engine at 05:08 UTC, lasting a little over 22 minutes. Reentry into Earth's atmosphere (100 km/60 mi AMSL) of the 15-year-old space station occurred at 05:44 UTC near Nadi, Fiji. Major destruction of the station began around 05:52 UTC and the unburned fragments fell into the South Pacific Ocean around 06:00 UTC. Visiting spacecraft Soyuz TM-24 docked with Mir as seen from the during STS-79|alt=An image of the four radial modules of the space station, with a Soyuz spacecraft, seen docked to the centre of the cluster. The Soyuz consists of a spherical orbital module, headlight-shaped descent module and cylindrical service module to which are attached two blue solar arrays. The entire spacecraft is covered in dark insulation except the base of the service module, which is white.Mir was primarily supported by the Russian Soyuz and Progress spacecraft and had two ports available for docking these spacecraft. Initially, the fore and aft ports of the core module could be used for dockings, but following the permanent berthing of Kvant-1 to the aft port in 1987, the rear port of the new module took on this role from the core module's aft port. Each port was equipped with the plumbing required for Progress cargo ferries to replace the station's fluids and also the guidance systems needed to guide the spacecraft in for docking. Two such systems were used on Mir; the rear ports of both the core module and Kvant-1 were equipped with both the Igla and Kurs systems, whilst the core module's forward port featured only the newer Kurs. Soyuz spacecraft provided manned access to and from the station allowing for crew rotations and cargo return, and also functioned as a lifeboat for the station, allowing for a relatively quick return to Earth in the event of an emergency. Two models of Soyuz flew to Mir; Soyuz T-15 was the only Igla-equipped Soyuz-T to visit the station, whilst all other flights used the newer, Kurs-equipped Soyuz-TM. A total of 31 (30 manned, 1 unmanned) Soyuz spacecraft flew to the station over a fourteen-year period. The unmanned Progress cargo vehicles were only used to resupply the station, carrying a variety of cargoes including water, fuel, food and experimental equipment. The spacecraft were not equipped with reentry shielding and so, unlike their Soyuz counterparts, were incapable of surviving reentry. As a result, when its cargoes had been unloaded, each Progress was refilled with rubbish, spent equipment and other waste which was destroyed, along with the Progress itself, on reentry. However, in order to facilitate cargo return, ten Progress flights carried Raduga capsules, which could return around 150 kg of experimental results to Earth automatically. Mir was visited by three separate models of Progress; the original 7K-TG variant equipped with Igla (18 flights), the Progress-M model equipped with Kurs (43 flights), and the modified Progress-M1 version (3 flights), which together flew a total of sixty-four resupply missions to the station. Whilst the vast majority of the Progress spacecraft docked automatically without incident, the station was equipped with a remote manual docking system, TORU, in case problems were encountered during the automatic approaches. With TORU cosmonauts could guide the spacecraft safely in to dock (with the exception of the catastrophic docking of Progress M-34, when the long-range use of the system resulted in the spacecraft's striking the station, damaging Spektr and causing decompression). In addition to the routine Soyuz and Progress flights, it was anticipated that Mir would also be the destination for flights by the Soviet Buran space shuttle, which was intended to deliver extra modules (based on the same "37K" bus as Kvant-1) and provide a much improved cargo return service to the station. Kristall carried two Androgynous Peripheral Attach System (APAS-89) docking ports designed to be compatible with the shuttle. One of these ports was to be used for Buran dockings with the other providing a berthing location for the planned Pulsar X-2 telescope, also to be delivered by Buran. The cancellation of the Buran programme, however, meant these capabilities were not realised until the 1990s when the ports were used instead by U.S. Space Shuttles as part of the Shuttle-Mir programme (after testing by the specially modified Soyuz TM-16 in 1993). Initially, visiting orbiters docked directly to Kristall, but this required the relocation of the module to ensure sufficient distance between the shuttle and Mir's solar arrays. In order to eliminate the need to move the module and retract solar arrays for clearance issues, a docking module was later added to the end of Kristall. The shuttles provided crew rotation of the American astronauts on station and carried cargo to and from the station, performing some of the largest transfers of cargo of the time. With a space shuttle docked to Mir, the temporary enlargements of living and working areas amounted to a complex that was the largest spacecraft in history at that time, with a combined mass of . ခရီးစဉ်ထိန်းချုပ်ရေးဌာန alt=A large room with two banks of computer workstations and their operators visible. On the wall facing these workstations are three large screens displaying a diagram of an orbital ground track, a space station crew and various other pieces of data, with a large ticker above these screens. Advertisement boards are situated below the screens.Mir and the spacecraft visiting the station were controlled from the Russian mission control centre () in Korolyov, near the RKK Energia plant. Referred to by its acronym ЦУП ("TsUP"), or simply as 'Moscow', the facility could process data from up to ten spacecraft in three separate control rooms, although each control room was dedicated to a single programme; one to Mir; one to Soyuz; and one to the Soviet space shuttle Buran (which was later converted for use with the ISS). The facility is now used to control the Russian Orbital Segment of the ISS. The flight control team were assigned roles similar to the system used by NASA at their mission control centre in Houston, including: The Flight Director, who provided policy guidance and communicated with the mission management team. The Flight Shift Director, who was responsible for real-time decisions within a set of flight rules, The Mission Deputy Shift Manager (MDSM) for the MCC was responsible for the control room's consoles, computers and peripherals, The MDSM for Ground Control was responsible for communications, The MDSM for Crew Training was similar to NASA's 'capcom,' or capsule communicator. This person generally had served as the Mir crew's lead trainer. Safety aspects Aging systems and atmosphere In the later years of the programme, particularly during the Shuttle-Mir programme, Mir suffered from various systems failures as the station aged. The station was originally designed to fly for five years but eventually flew for three times that length of time, and in the 1990s was showing its age—constant computer crashes, loss of power, uncontrolled tumbles through space and leaking pipes were an ever-present concern for crews. NASA astronaut John Blaha's account of the air quality on Mir - "very healthy, – it's not dry, it's not humid. Nothing smells." - contradicts sharply the concerns about air quality on the space station that Jerry Linenger relates in his book about his time on the facility. Linenger says that due to the age of the space station, the cooling system on board had developed a plethora of tiny leaks too small and numerous to be repaired, that permitted the constant release of coolant, making it unpleasant to breathe the air on board. He says that it was especially noticeable after he had made a spacewalk and become used to the clean air he had been breathing in his spacesuit. When he returned to the station and again began breathing the air inside Mir, he was deeply shocked by the intensity of the chemical smell and very worried about the possible negative health effects of breathing such heavily contaminated air. Various breakdowns of Mirs Elektron oxygen-generating system were also a concern. These breakdowns led crews to become increasingly reliant on the backup Vika solid-fuel oxygen generator (SFOG) systems, responsible for the fire during the handover between EO-22 and EO-23. (see also ISS ECLSS) မတော်တဆဖြစ်ရပ်များ alt=A white panel covered in buttons, which shows signs of fire damage on its bottom edge. Wiring and other pieces of hardware are arrayed beneath the panel. During the operation of Mir, a number of accidents occurred which threatened the safety of the station, such as the glancing collision between Kristall and Soyuz TM-17 during proximity operations in January 1994. The three most alarming incidents, however, occurred during EO-23. The first of these, on 23 February 1997 during the handover period from EO-22 to EO-23, followed a malfunction in one of the station's backup Vika system, a chemical oxygen generator later known as solid-fuel oxygen generator (SFOG). The Vika malfunction led to a fire which burned for around 90 seconds (according to official sources at the TsUP; astronaut Jerry Linenger, however, insists the fire burned for around 14 minutes), and produced large amounts of toxic smoke that filled the station for around 45 minutes. This forced the crew to don respirators, but some of the respirator masks initially worn were broken. Some of the fire extinguishers mounted on the walls of the newer modules were immovable. The other two accidents which occurred during EO-23 concerned testing of the station's TORU manual docking system to manually dock Progress M-33 and Progress M-34. The tests were called in order to gauge the performance of long-distance docking in order to enable the cash-strapped Russians to remove the expensive Kurs automatic docking system from Progress spacecraft. However, due to malfunctioning equipment, both tests failed, with Progress M-33 narrowly missing the station and Progress M-34 striking Spektr and puncturing the module, causing the station to depressurise and leading to Spektr being permanently sealed off. This in turn led to a power crisis aboard Mir as the module's solar arrays produced a large proportion of the station's electrical supply, causing the station to power down and begin to drift, requiring weeks of work to rectify before work could continue as normal. ရောင်ခြည်များနှင့်ကမ္ဘာပတ်လမ်းကြောင်းမှအမှိုက်များ Space debris in low Earth orbit|alt=A diagram of the Earth surrounded by huge numbers of black dots, indicating tracked pieces of orbital debris. See adjacent text for details. Without the protection of the Earth's atmosphere, cosmonauts were exposed to higher levels of radiation from a steady flux of cosmic rays and trapped protons from the South Atlantic Anomaly. The station's crews were exposed to an absorbed dose of about 5.2 cGy over the course of a 115-day expedition, producing an equivalent dose of 14.75 cSv, or 1133 µSv per day. This is approximately half of that received from natural background radiation on Earth in a year. The radiation environment of the station was not uniform, however; closer proximity to the station's hull led to an increased radiation dose, and the strength of radiation shielding varied between modules; Kvant-2's being better than the core module, for instance. The increased radiation levels result in a higher risk of crews developing cancer, and can cause damage to the chromosomes of lymphocytes. These cells are central to the immune system and so any damage to them could contribute to the lowered immunity experienced by cosmonauts. Over time, lowered immunity results in the spread of infection between crew members, especially in such confined areas. Radiation has also been linked to a higher incidence of cataracts in cosmonauts. Protective shielding and protective drugs may lower the risks to an acceptable level, but data is scarce and longer-term exposure will result in greater risks. At the low altitudes at which Mir orbited there is a variety of space debris, consisting of everything from entire spent rocket stages and defunct satellites, to explosion fragments, paint flakes, slag from solid rocket motors, coolant released by RORSAT nuclear powered satellites, small needles, and many other objects. These objects, in addition to natural micrometeoroids, posed a threat to the station as they have the ability to puncture pressurised modules and cause damage to other parts of the station, such as the solar arrays. Micrometeoroids also posed a risk to spacewalking cosmonauts, as such objects could puncture their spacesuits, causing them to depressurise. Meteor showers in particular posed a significant risk to the station, and, during such storms, the crews slept in their Soyuz ferries to facilitate an emergency evacuation should Mir be damaged. မှီငြမ်း ပြင်ပချိတ်ဆက်ရန်များ NASA animation of Mir'''s deorbit . Mir Diary Site containing detailed diagrams, pictures and background info Site contains information on problems aboard Mir Shuttle-Mir: Phase 1 Program Joint Report Mir Space Station (NASA Book) Category:အာကာသစခန်းများ။