International Space Station
| International Space Station | ||||
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| ISS Statistics | ||||
| Crew: | 2 | As of March 5, 2006 | ||
| Perigee: | 352.8 km | " | ||
| Apogee: | 354.2 km | " | ||
| Orbital period: | 91.61 minutes | " | ||
| Inclination: | 51.64 degrees | " | ||
| Orbits per day: | 15.72 | " | ||
| Days in orbit: | 2,473 | August 28, 2005 | ||
| Days occupied: | 1,759 | " | ||
| Total orbits: | 38,694 | " | ||
| Distance traveled: | ≈1,400,000,000 km | June 17, 2005 | ||
| Average speed: | 27,685.7 km/h | " | ||
| Mass: | 183,283 kg | August 28, 2005 | ||
| Living volume: | 425 m³ | " | ||
| International Space Station | ||||
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| ISS Diagram | ||||
The International Space Station (ISS) is a joint project of five space agencies: the National Aeronautics and Space Administration (United States), the Russian Federal Space Agency (Russian Federation), the Japan Aerospace Exploration Agency (Japan), the Canadian Space Agency (Canada) and the European Space Agency (Europe)[1].
The Brazilian Space Agency (Brazil) participates through separate contract with NASA. The Italian Space Agency similarly has separate contracts for various activities not done in the framework of ESA ISS works (where Italy also fully participates).
The space station is located in orbit around the Earth at an altitude of approximately 360 km (220 miles), a type of orbit usually termed low Earth orbit (The actual height varies over time by several kilometres due to atmospheric drag and reboosts [2]). It orbits Earth in a period of about 92 minutes; by June 2005 it had completed more than 37,500 orbits since launch of the Zarya module on November 20, 1998.
In many ways the ISS represents a merger of previously planned independent space stations: Russia's Mir 2, United States' Space Station Freedom and the planned European Columbus and Japanese Experiment Module.
Due to the ISS, there is a permanent human presence in space, as the ISS crew size has been at all times at least two since the first permanent crew entered the ISS on November 2, 2000. It is serviced primarily by the Soyuz, Progress spacecraft units and Space Shuttle. The ISS is currently still under construction with a projected completion date of 2010. At present, the station has a capacity for a crew of three. So far, all permanent crewmembers have come from the Russian or United States space programs. The ISS has however been visited by astronauts from a large number of other countries and was also the destination of the first three space tourists.
History
In the early 1980s NASA planned Space Station Freedom as a counterpart to the Soviet Salyut and Mir space stations. It never left the drawing board and with the end of the Soviet Union and the Cold War, it was cancelled. The end of the Space race prompted the US administration to start negotiations with international partners, Europe, Russia, Japan and Canada in the early 1990s, in order to build a truly international space station. This project was first announced in 1993 and was called Space Station Alpha. It was planned to combine the planned space stations of all participating space agencies: NASA's Space Station Freedom, Russia's successor project to Mir, the Mir-2 and ESA's Columbus Laboratory Module that was planned to be a stand-alone spacelab.
Throughout the 1990s, construction delays hit the project, budget projections were heavily revised and the ISS structure was modified frequently. The ISS has been, as of today, far more expensive than originally anticipated. The ESA estimates the overall cost from the start of the project in the late 1980s to the prospective end in 2016 to be in the region of €100 billion [3].
The first section, the Zarya Functional Cargo Block, was put in orbit in November 1998 on a Russian Proton rocket. Two further pieces (the Unity Module and Zvezda service module) were added before the first crew, Expedition 1, was sent. Expedition 1 docked to the ISS on November 2, 2000 and consisted of US astronaut William Shepherd and two Russian cosmonauts, Yuri Gidzenko and Sergei Krikalev.
ISS construction is now far behind the original planned schedule for completion of the ISS in 2004 or 2005. This is mainly due to the halting of all NASA Shuttle flights following the Columbia disaster in early 2003 (although there had been prior delays due partly to Shuttle problems, and partly to delays stemming from the Russian space agency's budget constraints). For the two and a half years that the NASA Space Shuttle fleet was grounded, crew rotation continued on the station through the use of the Russian Soyuz spacecraft, but construction of the ISS was halted and the science conducted aboard was limited due to the crew size of two.
The reappearance of the foam debris problem on the STS-114 mission in July 2005 (the same problem that doomed Columbia) has again delayed the launch sequence in 2005. As of 2006, the station is only able to accommodate three permanent crew members, compared to the expected six that the completed station will be home to.
In March 2006, a meeting of the heads of the five participating space agencies [4] accepted the new ISS construction schedule that plans to complete the ISS by 2010. A crew of six is expected to be established in 2009, after the Shuttle's next 12 construction flights following the second Return to Flight mission STS-121. Requirements for stepping up the crew size include enhanced environmental support on the ISS, a second Soyuz permanently docked on the station to function as a second 'lifeboat', more frequent Progress flights to provide double the amount of consumables, more fuel for orbit raising maneouvers, and a sufficient supply line of experimental equipment.
Building the ISS
As of the beginning of 2006 many changes have been made to the originally planned ISS, modules and other structures have been cancelled or replaced and the number of Shuttle flights to the ISS has been reduced from previously planned numbers. Still, the newest ISS Shuttle launch manifest and the current ISS design scheme reveal that more than 80% of the hardware planned to be part of the ISS in the late 90s will be orbited to the ISS by its scheduled completion date in 2010.
Building the ISS requires more than 40 assembly and utilization flights. Of these flights, currently 33 are planned to be Space Shuttle flights, with 17 ISS-shuttle flights currently flown and 16 more planned between 2006 and 2010. Other assembly flights consist of modules lifted by the Russian Proton rocket or in the case of the Pirs Airlock by a Soyuz rocket.
In addition to the assembly and utilization flights, approximately 30 Progress spacecraft flights are required to provide logistics until 2010. Experimental equipment, fuel and consumables are and will be delivered by all vehicles visiting the ISS, the Shuttle, the Russian Progress, the European ATV (prospectively from May 2007 onwards) and the Japanese HTV.
When assembly is complete, the ISS will have a pressurized volume of approximately 1,000 cubic meters, a mass of approximately 400,000 kilograms, approximately 100 kilowatts of power output, a truss 108.4 meters long, modules 74 meters long, and a crew of six.
As of early 2006 the station consists of several modules and elements:
| Element | Flight | Launch Vehicle | Launch date | Length (m) |
Diameter (m) |
Mass (kg) |
|---|---|---|---|---|---|---|
| Zarya FGB | 1A/R | Proton rocket | 20 Nov 1998 | 12.6 | 4.1 | 19,323 |
| Unity Node 1 | 2A - STS-88 | Endeavour | 4 Dec 1998 | 5.49 | 4.57 | 11,612 |
| Zvezda Service Module | 1R | Proton rocket | 12 Jul 2000 | 13.1 | 4.15 | 19,050 |
| Z1 Truss | 3A - STS-92 | Discovery | 11 Oct 2000 | 4.9 | 4.2 | 8,755 |
| P6 Truss - Solar Array | 4A - STS-97 | Endeavour | 30 Nov 2000 | 73.2 | 10.7 | 15,900 |
| Destiny | 5A - STS-98 | Atlantis | 7 Feb 2001 | 8.53 | 4.27 | 14,515 |
| Canadarm2 | 6A - STS-100 | Endeavour | 19 Apr 2001 | 17.6 | 0.35 | 4,899 |
| Joint Airlock - Quest Airlock | 7A - STS-104 | Atlantis | 12 Jul 2001 | 5.5 | 4.0 | 6,064 |
| Docking Compartment - Pirs Airlock | 4R | Progress M | 14 Aug 2001 | 4.1 | 2.6 | 3,900 |
| S0 Truss | 8A - STS-110 | Atlantis | 8 Apr 2002 | 13.4 | 4.6 | 13,970 |
| Mobile Base System for Canadarm2 | UF-2 - STS-111 | Endeavour | 5 Jun 2002 | 5.7 | 2.9 | 1,450 |
| S1 Truss | 9A - STS-112 | Atlantis | 7 Oct 2002 | 13.7 | 3.9 | 12,598 |
| P1 Truss | 11A - STS-113 | Endeavour | 24 Nov 2002 | 13.7 | 3.9 | 12,598 |
| External Stowage Platform (ESP-2) | LF1 - STS-114 | Discovery | 26 Jul 2005 | ? | ? | ? |
ISS structures and design
A total of 10 main pressurized modules (Zarya, Zvezda, US Lab, Node 1, Node 2, Node 3, Columbus, Kibo, MLM and the RM) are currently scheduled to be part of the ISS by its completion date in 2010. A number of smaller pressurized sections will be adjunct to them (Soyuz spacecrafts (permanently 2 as lifeboats - 6 months rotations), Progress transporters (2 or more), the Quest and Pirs Airlocks, as well as periodically the MPLM, the ATV and the HT-V).
Pressurized modules already launched
Currently the ISS consists of only four main pressurized modules; two Russian modules Zarya and Zvezda and two US modules Destiny and Node 1. Zarya was the first module launched by a Proton rocket in November, 1998, followed by a shuttle mission that connected Zarya with Node 1, the first of three node modules, 2 weeks after Zarya had been launched. This bare 2-module core of the ISS remained unmanned for the next one and a half years, until in July 2000 the Russian module Zarya was added, allowing a minimum crew of two astronauts or cosmonauts to be on the ISS permanently.
Since 2000 the only main pressurized module delivered to the ISS was the Destiny Laboratory Module by STS-98 in 2001. The US Lab was also the first science module delivered to the ISS, whereas Zarya provides electrical power, storage, propulsion, and guidance functions and Zvezda provides living quarters, a life support system, a communication system, electrical power distribution, a data processing system, a flight control system, and a propulsion system. Node 1's primary function is to link different modules together, however fluids, environmental control and life support systems, electrical and data systems are also routed through Node 1 to supply work and living areas of the station.
Other pressurized sections of the current configuration of the ISS are the Quest Airlock and the Pirs Airlock. Soyuz spacecrafts and Progress spacecrafts docked to the ISS also extend the pressurized volume. At least one Soyuz spacecraft has to stay docked permanently as a 'lifeboat' and is replaced every six months by a new Soyuz as part of crew rotation.
Although not permanently docked with the ISS, the Multi-Purpose Logistics Module (MPLM) forms part of the ISS during Shuttle missions that include the MPLM. The MPLM is attached to Node 1 and is used for resupply and logistics flights. Speculation that the last Space Shuttle flight involving an MPLM could leave one MPLM permanently docked with the Station are fueled by the MPLM's potential capacity for a long-term stay in orbit. Modifications would need to be made, including power support and checks on whether the MPLM would influence the ISS overall structure. As of 2006, it is not planned to integrate the MPLM permanently into the ISS structure.
Pressurized modules to be launched
Node 2 - 2007
As of March, 2006, nearly all already built pressurized modules are planned to be launched by the Shuttle after return to flight with STS-121 in July, 2006. If the current Shuttle launch sequence is not disrupted materially, Node 2 will be launched in the second quarter of 2007. Node 2 was built by the Italian Space Agency, however its ownership has been already transferred to NASA as part of a bartering agreement between NASA and ESA [5]. Node 2 will contain eight racks that provide air, electrical power, water and other systems essential to support life on the spacecraft and is scheduled to be the hub for the Columbus module and Kibo.
Columbus Laboratory Module - 2007
The next Shuttle flight after Node 2 is scheduled to bring the European module Columbus to the ISS. Columbus will be the second module mainly dedicated to science on the ISS, including the Fluid Science Laboratory (FSL), the European Physiology Modules (EPM), the Biolab, the European Drawer Rack (EDR) and various storage racks.
The Russian space agency has announced that the Multipurpose Laboratory Module (MLM) is scheduled to be launched by a Proton rocket in November 2007. The MLM is the main Russian science module, the third science module to be launched to the ISS. It will be equipped with an altitude control system that can be used as a backup by the ISS and will be docked onto the Zarya control module side docking port. The European Robotic Arm will be launched together with MLM, mated on its surface for a later deployment in space, according to a €20 million agreement signed in October 2005 between ESA and Roskosmos.
Japanese Experiment Module - 2008/2009
The Japanese Experiment Module (JEM), aka KIBO is the next pressurized module on the schedule. It consists of two pressurized sections and one exposed facility. Three Shuttle flights are needed to bring KIBO into orbit; the pressurized sections are scheduled to fly in the second half of 2008 and in the first half of 2009. Kibo will be mounted on the Node 2, on the opposite side to the Columbus module.
Although it has been speculated that Node 3 has been cancelled, it is still in the new launch manifest, currently scheduled for the end of 2009. Like Node 2, Node 3 was built in Italy by the Italian Space Agency, but is owned by NASA. It will be used as a storage compartment; however its original purpose, to be a hub for the Habitation Module as well as the Crew Return Vehicle, is no longer relevant, as both items were cancelled in 2001. One of the curiosities of the ISS, the 'space window' Cupola is currently scheduled to be flown together with Node 3 on the last shuttle flight to the ISS. ESA has already finished construction and is storing the Cupola until its flight together with Node 3.
Russian Research Module - 2009
NASA ISS schedule still includes one Russian Research Module (RM) as part of the ISS that may be docked to Zvezda and is rumoured to fly to the ISS in 2009 on a Russian Proton rocket. Construction on this module has not yet begun, which casts doubt on its actual delivery to the ISS.
Unpressurized elements
There is also a large unpressurized truss system partially in place that will eventually support the prominent solar arrays.
Cancelled elements
- Centrifuge Accommodations Module - cancelled, would have been attached to Node 2
- Universal Docking Module - cancelled, replaced by (MLM - FGB2)
- Docking and Stowage Module - cancelled
- Habitation Module - cancelled
- Crew Return Vehicle (CRV) - cancelled
- Interim Control Module - cancelled, no need to replace Zvezda
- ISS Propulsion Module - cancelled, no need to replace Zvezda
- Science Power Platform - cancelled, power will be provided to the Russian segments partly by the US solar cell platforms
Visiting spacecraft
- Space Shuttle - resupply vehicle, assembly and logistics flights and crew rotation
- Soyuz spacecraft - crew rotation and emergency evacuation, replaced every 6 months
- Progress spacecraft - resupply vehicle
- Proposed: European (ESA) Automated Transfer Vehicle (ATV) ISS resupply spacecraft (scheduled for May 2007)
- Proposed: Japanese (JAXA) H-II Transfer Vehicle (HTV) resupply vehicle for KIBO module (scheduled for 2008)
- Proposed: Commercial cargo resupply spacecraft, under the NASA COTS (Commercial Orbital Transportation Services) program (Program ends 2010)
- Proposed: Russian Space Shuttle Kliper for possible crew rotation and as resupply transporter (scheduled for 2012)
- Proposed: Crew Exploration Vehicle possible crew rotation and as resupply transporter (scheduled for 2011 or 2012)
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Criticism of the ISS
There are many critics of the ISS, especially with regard to the biggest partner NASA. These critics view the project as a waste of time and American tax money, inhibiting progress on more useful projects: for instance, the very often quoted estimated $100 billion USD lifetime cost could pay for dozens of unmanned scientific missions or could be used for space exploration in general or be better spent on problems on Earth.
Critics point to the fact that very little high-quality scientific research has been done on the ISS, although it has been in orbit for 8 years already of which it has been manned for more than 5 years. Delay to the ISS during 2003-2006 was mainly due to problems with the shuttle program, rather than ISS specific failures. Others criticise that cuts to the ISS structure also include ambitious science modules, such as the Centrifuge Accommodations Module, a pressurized module that would include a centrifuge for experiments in lower gravity and say that the currently planned complete ISS structure is far from being the full-fledged science platform planned in the 1990s.
Advocates of space exploration say that criticism of the ISS project is short-sighted, and that manned space research and exploration have produced billions of dollars' worth of tangible benefits to people on Earth. By some estimates, the indirect economic benefits made from commercialization of technologies developed during manned space exploration have returned many times the initial investment to the economy. However, there is no consensus among economists on how to make such an estimate, since it requires speculation as to what the tax money would have accomplished had it remained in the economy. Whether the ISS, as distinct from the wider space program, will be a major contributor in this sense is thus a subject of debate. More cynical advocates have pointed out that even if its scientific value is nil, it would have still served to force international cooperation at a time of tough international politics.
Two technical aspects of the ISS's design have been heavily criticized: (1) it requires too much maintenance, and in particular too much maintenance by risky, expensive EVAs; (2) its orbit is too highly inclined, making it difficult to reach from the Earth's surface in an economical way. The latter decision arose from the political realities of the US's desire to keep Russia involved in the program.
Space tourism, weddings and the ISS
The ISS has seen the first space tourist, Dennis Tito, who spent USD 20 million to fly aboard a Russian supply mission and the first space wedding when Yuri Malenchenko on the station married Ekaterina Dmitriev who was in Texas.
Present status of the ISS
After the breakup of Columbia on February 1, 2003, and the subsequent two and a half year suspension of the US space program, followed by problems with resuming flight operations in 2005, there was some uncertainty over the future of the ISS until 2006. In 2006 the international partners announced their commitment to complete the ISS by 2010.
Still the future of the ISS depends on the Space Shuttle. Due to weight restrictions and design constraints, payloads intended for the Shuttle - even if ready to fly - cannot be launched (in a economically sensible way) to the station on any other available launcher. In addition, assembly work is manpower-intensive, making it difficult to do without the assistance of EVA teams brought up by the Shuttle. Thus, if the Shuttle program suffered another disaster or a severe cut, the ISS project could probably not be continued.
Since 2003 crew exchange has been carried out using the Russian Soyuz spacecraft. Starting with Expedition 7, two-astronaut caretaker crews have been launched, instead of the previous crews of three. Because the ISS had not been visited by a shuttle for an extended period, a larger than planned amount of waste accumulated, temporarily hindering station operations in 2004. However Progress transports and the STS-114 shuttle flight took care of this problem.
The Space Shuttle Program resumed flight on 26 July 2005 with the STS-114 mission of Discovery. This mission to the ISS was intended both to test new safety measures implemented since the Columbia disaster, and to deliver supplies to the station. Although the mission succeeded safely, it was not without risk; foam was shed by the external tank, leading NASA to announce future missions would be grounded until this issue was resolved.
The second Return to Flight mission, STS-121 was planned for September 2005, but Discovery's flight preparation has been delayed until at least May 2006. ISS construction will continue in 2006, if all goes well with STS-121 with a launch in August by Atlantis and probably another launch by Discovery in December.
ISS Expeditions
The International Space Station is the most-visited spacecraft in the history of space flight. As of August 28, 2005, it has had 141 (non-distinct) visitors. Mir had 137 (non-distinct) visitors (See Space station).
See also
ISS-related articles
- List of International Space Station visitors
- List of ISS spacewalks performed from the ISS or visiting spacecraft
- List of manned spaceflights to the ISS for a comprehensive chronological list of all manned spacecraft that have visited the ISS, including the spacecraft's respective crews
- List of unmanned spaceflights to the ISS — Progress supply flights and unmanned automatic docking space station modules
Other
- Space station for statistics of occupied space stations
- Salyut
- Skylab
- Mir
- Soyuz spacecraft
- Progress spacecraft
- Kliper
- Transhab
- space flight simulator
- Herman Potočnik
Footnotes
- ^ 10 of its member states are currently participating [6]; Austria, United Kingdom, Ireland, Portugal, and Finland chose not to participate; Greece and Luxembourg joined ESA later.
- ^ The image on the right side despicts a graph of the altitude of the ISS since launch in 1998.
- ^ The Columbus module will be flown to the ISS by Shuttle in return for ESA manufacturing both Node 2 and Node 3 for NASA.
External links
- SpaceRef - Regularly updated detailed status reports of the station.
- ISS Familiarization and Training Manual - NASA July 1998 (PDF format)
- Current ISS Vital Statistics
- NASA 3D Java Tracker for ISS and other Satellites
- International Space Station — CSA Site
- International Space Station — Energia site
- International Space Station — ESA site
- International Space Station — JAXA site
- International Space Station — AEB site
- International Space Station — NASA site
- International Space Station — EuroNews report (Real player video stream)
- International Space Station from Encyclopedia Astronautica
- NASA Space Partnership Development
- NASA Commercial Orbital Transportation Services program
- Spacelink — Space Product Development
- The Planetary Society
- http://www.seds.org/pub/seds/National/misc/why-space
- Solar Transit: ISS with Discovery — The ISS with STS-114 transit the sun.
- See the ISS from your home town
- Heavens Above — locate ISS, and find when to view it, from any location.
- NASA Human Spaceflight - ISS Assembly Sequence webpage and ISS sighting by city
- Unofficial Shuttle Launch Manifest
- Track the ISS with Google Maps
- ISS Fanclub
- Detailed list of canceled components
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