The International Space Station (ISS)

International Space Station

The International Space Station (ISS) is a habitable artificial satellite in low Earth orbit. It follows the Salyut, Almaz, Skylab and Mir stations as the ninth space station to be inhabited. The ISS is a modular structure whose first component was launched in 1998.^[8] Now the largest artificial body in orbit, it can often be seen at the appropriate time with the naked eye from Earth.^[9] The ISS consists of pressurised modules, external trusses, solar arrays and other components. ISS components have been launched by American Space Shuttles as well as Russian Proton and Soyuz rockets.^[10] Budget constraints led to the merger of three space station projects with the Japanese Kibō module and Canadian robotics. In 1993 the partially built components for a Soviet/Russian space station Mir-2, the proposed American Freedom, and the proposed European Columbus merged into a single multinational programme.^[10]

 

The ISS serves as a microgravity and space environment research laboratory in which crew members conduct experiments in biology, human biology, physics, astronomy, meteorology and other fields.^[11][12][13] The station is suited for the testing of spacecraft systems and equipment required for missions to the Moon and Mars.^[14]

 

The station has been continuously occupied for 700112000000000000012 years and 7002155000000000000155 days, having exceeded the previous record of almost 10 years (or 3,634 days) held by Mir, in 2010. The station is serviced by Soyuz spacecraft, Progress spacecraft, the Automated Transfer Vehicle, the H-II Transfer Vehicle,^[15] and the Dragon spacecraft. It has been visited by astronauts and cosmonauts from 15 different nations.^[16]

The ISS programme is a joint project between five participating space agencies: NASA, the Russian Federal Space Agency, JAXA, ESA, and CSA.^[15][17] The ownership and use of the space station is established by intergovernmental treaties and agreements.^[18] The station is divided into two sections, the Russian orbital segment (ROS) and the United States orbital segment (USOS), which is shared by many nations. The ISS is maintained at an orbital altitude of between 330 km (205 mi) and 435 km (270 mi). It completes 15.7 orbits per day.^[19] The ISS is funded until 2020, and may operate until 2028.^[20][21][22] The Russian Federal Space Agency (RSA/RKA) has proposed using ISS to commission modules for a new space station, called OPSEK, before the remainder of the ISS is de-orbited.

Purpose

 

According to the original Memorandum of Understanding between NASA and RSA, the International Space Station was intended to be a laboratory, observatory and factory in space. It was also planned to provide transportation, maintenance, and act as a staging base for possible future missions to the Moon, Mars and asteroids.^[23] In the 2010 United States National Space Policy, the ISS was given additional roles of serving commercial, diplomatic^[24] and educational purposes.^[25]

  Scientific research

Main article: Scientific research on the ISS

The ISS provides a platform to conduct scientific research that cannot be performed in any other way. While small unmanned spacecraft can provide platforms for zero gravity and exposure to space, space stations offer a long term environment where studies can be performed potentially for decades, combined with ready access by human researchers over periods that exceed the capabilities of manned spacecraft.^[16][26]

 

The Station simplifies individual experiments by eliminating the need for separate rocket launches and research staff. The primary fields of research include Astrobiology, astronomy, human research including space medicine and life sciences, physical sciences, materials science, space weather and weather on Earth (meteorology).^{[11][12][13][27][28]} Scientists on Earth have access to the crew's data and can modify experiments or launch new ones, benefits generally unavailable on unmanned spacecraft.^[26] Crews fly expeditions of several months duration, providing approximately 160 man-hours a week of labour with a crew of 6.^[11][29]

 

Kibō is intended to accelerate Japan's progress in science and technology, gain new knowledge and apply it to such fields as industry and medicine.^[30]

In order to detect dark matter and answer other fundamental questions about our universe, engineers and scientists from all over the world built the Alpha Magnetic Spectrometer (AMS), which NASA compares to the Hubble telescope, and says could not be accommodated on a free flying satellite platform due in part to its power requirements and data bandwidth needs.^[31][32] On 3 April 2013, NASA scientists reported that hints of dark matter may have been detected by the Alpha Magnetic Spectrometer.^{[33][34][35][36][37][38]} 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.^[39] Some simple forms of life called extremophiles,^[40] including small invertebrates called tardigrades^[41] can survive in this environment in an extremely dry state called desiccation.

 

Medical research improves knowledge about the effects of long-term space exposure on the human body, including muscle atrophy, bone loss, and fluid shift. This data will be used to determine whether lengthy human spaceflight and space colonisation are feasible. As of 2006, data on bone loss and muscular atrophy suggest that there would be a significant risk of fractures and movement problems if astronauts landed on a planet after a lengthy interplanetary cruise, such as the six-month interval required to travel to Mars.^[42][43] 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 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.^[44][45][46]