FEATURE ARTICLE A Station in Space Anand Kumar Sharma HE Indian Space Research Organisation (ISRO) has The Space Station provides a relatively safe Low Earth recently made a quantum leap in space technology by Orbit platform, to test spacecraft systems for long-duration Ttaking up the ‘Gaganyaan’ project under the Human missions to the Moon, Mars, Venus, etc. It serves as a research Space Flight Programme. As a follow-up programme of the laboratory to conduct scientific experiments in biology, Gaganyaan, India plans to build a space station in the time physics, astronomy, meteorology, etc. in microgravity and frame of 2027-2030. space environment. A space station, also known as an orbital station or an Until now, two types of space stations have been flown: orbital space station, is a spacecraft capable of supporting a monolithic and modular. Monolithic stations consist of one- human crew in orbit for an extended period of time. It is piece spacecraft placed in orbit with a single launch. Early a complex vehicle that must incorporate many interrelated stations were of monolithic designs (1971-1986) containing subsystems, including structure, electrical power, thermal all their supplies and experimental equipment. A crew would control, altitude determination and control, orbital navigation, then be launched to join the station and perform research. propulsion, automation, robotics, communications, Modular stations consist of two or more separate vehicles environmental control, life support, crew facilities and cargo that are launched independently and docked in orbit. Modular transportation. The space station must have docking ports to structures allow easy addition or removal of the existing units. allow other spacecraft to dock to transfer crew and supplies. Modular stations are currently preferred due to lower costs However, it lacks major propulsion or landing systems. and greater flexibility. The first space station, Salyut-1 (Image credit: Wikipedia) 36 | Science Reporter | September 2020 The first space station was Salyut 1 launched by the weight of an average car. The ISS travels at an average speed erstwhile Soviet Union on 19 April 1971. America’s first of 27,724 kilometres per hour and completes 15.54 orbits per space station, Skylab, was launched in 1973. The next Soviet day (93 minutes per orbit). space station Mir (1986), unlike previous stations, had a Crews aboard the ISS are assisted by mission control modular design; first a core unit was launched and then the centres in Houston and Moscow and a payload control centre additional modules with a specific role were added. in Huntsville. Other international mission control centres The International Space Station (ISS) is the ninth support the space station from Japan, Canada and Europe. inhabited space station, following the Soviet and later Russian As per the current plans, the space station will be operated Salyut-1,4,6,7 (1971, 1974, 1977, 1982), Almaz (also known by at least 2024 and could be expanded by 2030. Afterwards, as Salyut-3 & 5; 1974, 1976) and Mir (1986) stations as well plans for the space station are not clearly laid out. It could be as Skylab (1973) from the US. deorbited, or recycled for future space stations. The China National Space Administration (CNSA) had The ISS has been described as the most expensive single launched two prototype space stations, Tiangong-1 & 2 during item ever constructed. In 2010 its inflation-unadjusted cost 2011 and 2016. These stations with single crew member was estimated as US $150 billion (₹ 1,125,000 crores; 1 US $ capacity were operated for a short duration of 25-26 days. = ₹ 75). The contribution of participating agencies and shuttle flight expenses are: NASA - 74 billion US $; Russia - 12 International Space Station (ISS) billion US $; Europe - 5 billion US $; Japan - 5 billion US $, The International Space Station is the largest and most complex Canada-2 billion US $ and the cost of 36 shuttle flights is 52 structure humans have ever put into space and is built piece- billion US $. At the International Space Station, each person- by-piece in the orbit. The ISS programme is a joint project day cost is approximately $ 7.5 million (₹ 56.25 crores). between five participating space agencies: NASA (National Aeronautics and Space Administration, United States), Assembly and Integration Roscosmos (Russian State Corporation for Space Activities), The International Space Station is such a giant structure that JAXA (Japan Aerospace Exploration Agency, Japan), ESA it was impossible to build it on Earth and then launch into (European Space Agency, Europe) and CSA (Canadian Space space in one go because such a powerful rocket is still not Agency, Canada). The ownership and use of the space station available. So, the station was taken into space piece-by-piece are established by intergovernmental treaties and agreements. and gradually built in orbit by astronauts and robotics. It took The ISS is so large that it can often be seen with the naked 10 years and more than 30 missions to assemble. NASA’s eye from Earth. The length of the International Space Station space shuttle was used to carry most of the heavier pieces, is currently 73 m and width 108.5 m; which is larger than a although some individual modules were launched on single- football field. It weighs around 460,000 kg or 500 times the use rockets. A view of the International Space Station from space September 2020 | Science Reporter | 37 The station is divided into two sections, the Russian Bigelow Expandable Activity Module (BEAM) is an Orbital Segment (ROS), which is operated by Russia and the experimental expandable space station module of NASA United States Orbital Segment (USOS), which is shared by developed by Bigelow Aerospace. It is an experimental many nations. program to test and validate expandable habitat technology. The major structural components of the station can be grouped under two sections, pressurised and unpressurised. Five modules are still to be launched to ISS, including The pressurised sections are accessible by the crew without the Nauka, European Robotic Arm, Prichal module and two using spacesuits. While accessing the station’s unpressurised power modules called NEM-1 and 2. superstructure, space suits have to be used. Unpressurised Elements Pressurised Elements The ISS has a large number of external components that do not Zarya is the first module of the ISS. Although it was built require pressurisation. The largest of these is the Integrated by a Russian company, it is owned by the United States. Truss Structure (ITS). ITS consists of a linear arranged The module was equipped with propulsion, attitude control, sequence of connected trusses on which various unpressurized communication, electrical power systems, but lacked a components are mounted such as logistics carriers, radiators, long-term life support system. With the assembly of more solar arrays and other equipment. specialized modules, Zarya is currently used for storage. Unity connecting module, also known as Node 1, is the first Expeditions U.S. built component of the ISS. This cylindrical module The ISS has been visited by astronauts, cosmonauts and space connects the Russian and United States segments of the station tourists from 19 different nations. As of 31 May 2020, the where the crew take meals together. International Space Station has been visited by 240 people from 19 countries, many of them multiple times. The United Zvezda service module is the third component of the ISS and States sent 151 people, Russia sent 48, nine were Japanese, provides the life support systems to the station. eight Canadian, five Italian, four French, three German and one each from Belgium, Brazil, Denmark, Kazakhstan, Destiny module, also known as the U.S. Lab, is the Malaysia, the Netherlands, South Africa, South Korea, Spain, primary operating facility for U.S. research payloads on the Sweden, the United Arab Emirates and the United Kingdom. International Space Station (ISS). Quest Joint Airlock, is the primary airlock for the ISS Challenges of Space Station designed to host spacewalks with Extravehicular Mobility. Why is the installation and maintenance of the space station so challenging? The space environment is hostile to Pirs and Poisk are two Russian airlock modules. life. Unprotected presence in space is characterised by an Harmony, also known as Node 2, is the “utility hub” of the intense radiation field, high vacuum, extreme temperatures ISS. Sleeping cabins for four crew are housed here. Harmony and microgravity. Making a pressurized module where the is made out of stainless steel and weighs approx. 14,288 kg. astronauts can live in Earth-like conditions in space and then bring them back to Earth after the expedition are arduous Tranquility, also known as Node 3, provides six berthing tasks. Any manned mission to space presents a massive locations with environmental control and an observation technological challenge because there is absolutely no room cupola. for any error when the safety of astronauts is concerned. It is imperative to master the following key technologies Columbus is the science laboratory of ESA. for the establishment of a space station: Kibo is the Japanese Experiment Module (JEM), a science • Design of Pressurized Module laboratory of JAXA. The exposed facility is known as “Terrace” is located outside the port cone. All experiment • Construction of Heavy Lift Launch Vehicles payloads are fully exposed to the space environment. • Environmental Control and Life Support System Cupola is an ESA-built observatory module attached to the • Launch Escape System Tranquility (Node 3) module. Its seven windows are used to conduct experiments, dockings and observations of Earth. • Docking, Un-docking, Rendezvous Rassvet, also known as the Mini-Research Module 1 (MRM- • Atmospheric Re-Entry Capability 1), is used for cargo storage and as a docking port for visiting • Space Suits and Parachutes spacecraft. • Astronaut Training Leonardo Permanent Multipurpose Module of ESA is a • Waste Collection and Water Recovery System cargo way.