international space station (page 2)
Freedom with Kibō
Artist's conception of the proposed "Power Tower" space station with the Japanese Experiment Module attached
Approved by then-president Ronald Reagan and announced in the 1984 State of the Union Address, "We can follow our dreams to distant stars, living and working in space for peaceful economic and scientific gain", the proposed Freedom changed considerably.
NASA's first cost assessment in 1987 revealed the "Dual Keel" Station would cost $14.5 billion. This caused a political uproar in Congress, and NASA and Reagan Administration officials reached a compromise in March 1987 which allowed the agency to proceed with a cheaper $12.2-billion Phase One Station that could be completed after 10 or 11 Shuttle assembly flights. This design initially omitted the $3.4-billion 'Dual Keel' structure and half of the power generators. The new Space Station configuration was named Freedom by Reagan in June 1988. Originally, Freedom would have carried two 37.5 kW solar arrays. However, Congress quickly insisted on adding two more arrays for scientific users. The Space Station programme was plagued by conflicts during the entire 1984–87 definition phase. In 1987, the Department of Defense (DoD) briefly demanded to have full access to the Station for military research, despite strong objections from NASA and the international partners. Besides the expected furore from the international partners, the DoD position sparked a shouting match between Defense Secretary Caspar Weinberger and powerful members of Congress that extended right up to the final Fiscal 1988 budget authorisation in July 1987.[72] Reagan wanted to invite other NATO countries to participate in the US-led project, since the Soviet Union had been launching international crews to their Salyut space stations since 1971. At one point, then-anonymous disgruntled NASA employees calling themselves "Center for Strategic Space Studies" suggested that instead of building Freedom, NASA should take the back-up Skylab from display in the National Air and Space Museum in Washington and launch that.[73]
An agreement signed in September 1988 allocated 97% of the US lab resources to NASA while the Canadian CSA would receive 3% in return for its contribution to the programme. Europe and Japan would retain 51% of their own laboratory modules. Six Americans and two international astronauts would be permanently based on Space Station Freedom. Several NASA Space Shuttle missions in the 1980s and early 1990s included spacewalks to demonstrate and test space station construction techniques.
The Japanese Experiment Module (JEM), christened Kibō ("hope") in 1999, is Japan's first manned spacecraft. Kibō consists of a pressurised laboratory dedicated to advanced technology experiments, education and art, a cargo bay, an unpressurised pallet for vacuum experiments in space, a robotic arm, and interorbital communication system. While the proposed space station was redesigned many times around Kibō, the only significant change has been the placement of its ballistic shielding. Its final position at the front of the station increases the risk of damage from debris. The ESA and NASA, by contrast, both reduced the size of their laboratories over the course of the programme. The Japanese National Space Development Agency (NASDA) formally submitted the JEM proposal to NASA in March 1986, and by 1990 design work began.[67][74][75] Constructed in the Tobishima Plant of Nagoya Aerospace Systems Works, by Mitsubishi Heavy Industries, Ltd., Kibō made its way to the Tsukuba Space Center and in 2003 Kibō was shipped, first by river barge and then by ship, to America. In 2010, Kibō won the Good Design Award, a 56 year old consumer and industry award which identifies the best of Japanese craftsmanship.[76][77]
A decade before Zarya was launched into orbit, Japan was working on the development of its Hope-X spaceplane, intended to launch on the H-II rocket. Depending on the configuration of the rocket, it would have a mass of between 10 and 20 tonnes, and be able to carry both crew and cargo. It would launch vertically and land horizontally. The programme was terminated by JAXA in 2003 after scale mockup testing.[78][79]
Columbus
The first elements of the Columbus programme were expected to fly as early as 1992, to coincide with the 500th anniversary of Columbus' voyage to America.[citation needed] ESA and NASA disagreed over the concept of the Columbus programme in 1986: America objected to ESA's using Columbus as building block of a future European space station, and were concerned that they would facilitate the creation of a potential competitor if the manned space outpost fulfilled its promise as supplier of commercially viable products, such as new materials and pharmaceuticals.[citation needed] Plans were scaled down as a result, and by 1988, Europe proposed to participate with three elements, the Columbus module, the Man-Tended Free Flyer (MTFF), and the Polar Platform (PPF),[80] supported by the Ariane 5 rocket and the Hermes spaceplane.[81]
The Columbus Man-Tended Free Flyer (MTFF) was an ESA programme to develop a space station that could be used for a variety of microgravity experiments while serving ESA's needs for an autonomous manned space platform.[82][83] The MTFF would be a space station without long term life support, visited by short term crews to replenish and maintain experiments in a Zero-G environment free of vibrations caused by a permanent crew. The project was cancelled after budget constraints caused by German reunification. The Hermes spaceplane is comparable in function to the American and Soviet space shuttles, with a smaller crew of up to 6 (reduced to 3 with ejection seats after the Challenger disaster) and substantially smaller cargo capacity, 4,550 kg, comparable to ISS unmanned cargo ships.
By 1991 the Columbus and Hermes pre-development activities were good enough to progress into full development, however profound geopolitical changes prompted examining broader international cooperation, in particular with the Russian Federation. ESA Member States approved the complete development of the Attached Pressurised Module (APM) and the Polar Platform (PPF) for Columbus, but the Man-Tended Free-Flyer (MTFF) was abandoned. The Hermes programme was reoriented into the Manned Space Transportation Programme (MSTP), and a three-year period extending from 1993 to 1995 was agreed on in order to define a future manned space transportation system in cooperation with Russia, including joint development and use of Mir-2.[84][85]
Station structure
The ISS follows Salyut and Almaz series, Cosmos 557, Skylab, and Mir as the 11th space station launched, as the Genesis prototypes were never intended to be manned. The ISS is a third generation[86] modular space station.[87]
Other examples of modular station projects include the Soviet/Russian Mir, Russian OPSEK, and Chinese space station. The first space station, Salyut 1, and other one-piece or 'monolithic' first generation space stations, such as Salyut 2,3,4,5, DOS 2, Kosmos 557, Almaz and NASA's Skylab stations were not designed for re-supply.[88] Generally, each crew had to depart the station to free the only docking port for the next crew to arrive, Skylab had more than one docking port but was not designed for resupply. Salyut 6 and 7 had more than one docking port and were designed to be resupplied routinely during crewed operation.[89] Modular stations can allow the mission to be changed over time and new modules can be added or removed from the existing structure, allowing greater flexibility.
Below is a diagram of major station components. The blue areas are pressurised sections accessible by the crew without using spacesuits. The station's unpressurised superstructure is indicated in red. Other unpressurised components are yellow. Note that the Unity node joins directly to the Destiny laboratory. For clarity, they are shown apart.
Assembly
Partially constructed ISS in December 2002
Ron Garan during
STS-124 uses a computer controlled screwdriver for speed, torque and number of turns.
A crossection sketch shows how racks are fitted inside the station.
The assembly of the International Space Station, a major endeavour in space architecture, began in November 1998.[3] Russian modules launched and docked robotically, with the exception of Rassvet. All other modules were delivered by the Space Shuttle, which required installation by ISS and shuttle crewmembers using the SSRMS and EVAs; as of 5 June 2011, they had added 159 components during more than 1,000 hours of EVA activity. 127 of these spacewalks originated from the station, while the remaining 32 were launched from the airlocks of docked Space Shuttles.[2] The beta angle of the station had to be considered at all times during construction, as the station's beta angle is directly related to the percentage of its orbit that the station (as well as any docked or docking spacecraft) is exposed to the sun; the Space Shuttle would not perform optimally above a limit called the "beta cutoff".[90] Rassvet was delivered by NASA's Atlantis Space Shuttle in 2010 in exchange for the Russian Proton delivery of the United States-funded Russian-built Zarya Module in 1998.[91] Rassvet was attached to its docking port through use of the station's remote manipulator system.
The first module of the ISS, Zarya, was launched on 20 November 1998 on an autonomous Russian Proton rocket. It provided propulsion, attitude control, communications, electrical power, but lacked long-term life support functions. Two weeks later a passive NASA module Unity was launched aboard Space Shuttle flight STS-88 and attached to Zarya by astronauts during EVAs. This module has two Pressurized Mating Adapters (PMAs), one connects permanently to Zarya, the other allows the Space Shuttle to dock to the space station. At this time, the Russian station Mir was still inhabited. The ISS remained unmanned for two years, during which time Mir was de-orbited. On 12 July 2000 Zvezda was launched into orbit. Preprogrammed commands on board deployed its solar arrays and communications antenna. It then became the passive vehicle for a rendezvous with the Zarya and Unity. As a passive "target" vehicle, the Zvezda maintained a stationkeeping orbit as the Zarya-Unity vehicle performed the rendezvous and docking via ground control and the Russian automated rendezvous and docking system. Zarya's computer transferred control of the station to Zvezda's computer soon after docking. Zvezda added sleeping quarters, a toilet, kitchen, CO2 scrubbers, dehumidifier, oxygen generators, exercise equipment, plus data, voice and television communications with mission control. This enabled permanent habitation of the station.[92][93]
The first resident crew, Expedition 1, arrived in November 2000 on Soyuz TM-31. At the end of the first day on the station, astronaut Bill Shepherd requested the use of the radio call sign "Alpha", which he and cosmonaut Krikalev preferred to the more cumbersome "International Space Station".[94] The name "Alpha" had previously been used for the station in the early 90's,[95] and following the request, its use was authorised for the whole of Expedition 1.[96] Shepherd had been advocating the use of a new name to project managers for some time. Referencing a naval tradition in a pre-launch news conference he had said: "For thousands of years, humans have been going to sea in ships. People have designed and built these vessels, launched them with a good feeling that a name will bring good fortune to the crew and success to their voyage."[97] Yuri Semenov, the President of Russian Space Corporation Energia at the time, disapproved of the name "Alpha"; he felt that Mir was the first space station, and so he would have preferred the names "Beta" or "Mir 2" for the ISS.[96][98][99]
Expedition 1 arrived midway between the flights of STS-92 and STS-97. These two Space Shuttle flights each added segments of the station's Integrated Truss Structure, which provided the station with Ku-band communication for US television, additional attitude support needed for the additional mass of the USOS, and substantial solar arrays supplementing the station's existing 4 solar arrays.[100]
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 Destiny laboratory and Quest airlock, in addition to the station's main robot arm, the Canadarm2, and several more segments of the Integrated Truss Structure.
The expansion schedule was interrupted by the destruction of the Space Shuttle Columbia on STS-107 in 2003, with the resulting hiatus in the Space Shuttle programme halting station assembly until the launch of Discovery on STS-114 in 2005.[101]
Assembly resumed with the arrival of Atlantis on STS-115, which delivered the station's second set of solar arrays. Several more truss segments and 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 pressurised modules could be accommodated, and the Harmony node and Columbus European laboratory were added. These were followed shortly after by the first two components of Kibō. In March 2009, STS-119 completed 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 third node, Tranquility, was delivered in February 2010 during STS-130 by the Space Shuttle Endeavour, alongside the Cupola, closely followed in May 2010 by the penultimate Russian module, Rassvet, delivered by Space Shuttle Atlantis on STS-132. The last pressurised module of the USOS, Leonardo, was brought to the station by Discovery on her final flight, STS-133, followed by the Alpha Magnetic Spectrometer on STS-134, delivered by Endeavour.[citation needed]
As of June 2011, the station consisted of fifteen pressurised modules and the Integrated Truss Structure. Still to be launched are the Russian Multipurpose Laboratory Module Nauka and a number of external components, including the European Robotic Arm. Assembly is expected to be completed by December 2013, by which point the station will have a mass in excess of 400 tonnes (440 short tons).[3][102]
The gross mass of the station is not possible to calculate with precision. The total launch mass of the modules on orbit is 417,289 kg (919,960 lb) (as of 03/09/2011).[103] The mass of experiments, spare parts, personal effects, crew, foodstuff, clothing, propellants, water supplies, gas supplies, docked spacecraft, and other items add to the total mass of the station. Hydrogen gas is constantly vented overboard by the oxygen generators.
| Author: | Bling King |
| Published: | Sep 9th 2013 |
| Modified: | Sep 9th 2013 |
