(The Gist of Science Reporter) International Space Station (ISS)
(GIST OF SCIENCE REPORTER) International Space Station (ISS)
International Space Station (ISS)
The International Space Station is the largest and most complex structure humans have ever put into space and is built pieceby-piece in the orbit. The ISS programme is a joint project between five participating space agencies: NASA (National Aeronautics and Space Administration, United States), Roscosmos (Russian State Corporation for Space Activities), JAXA (Japan Aerospace Exploration Agency, Japan), ESA (European Space Agency, Europe) and CSA (Canadian Space Agency, Canada). The ownership and use of the space station are established by intergovernmental treaties and agreements.
The ISS is so large that it can often be seen with the naked eye from Earth. The length of the International Space Station is currently 73 m and width 108.5 m; which is larger than a football field. It weighs around 460,000 kg or 500 times the weight of an average car. The ISS travels at an average speed of 27,724 kilometres per hour and completes 15.54 orbits per day (93 minutes per orbit).
Crews aboard the ISS are assisted by mission control centres in Houston and Moscow and a payload control centre in Huntsville. Other international mission control centres support the space station from Japan, Canada and Europe. As per the current plans, the space station will be operated by at least 2024 and could be expanded by 2030. Afterwards, plans for the space station are not clearly laid out. It could be deorbited, or recycled for future space stations. The ISS has been described as the most expensive single item ever constructed. In 2010 its inflation-unadjusted cost was estimated as US $150 billion ( 1,125,000 crores; 1 US $ = 75). The contribution of participating agencies and shuttle flight expenses are: NASA - 74 billion US $; Russia – 12 billion US $; Europe - 5 billion US $; Japan - 5 billion US $,Canada-2 billion US $ and the cost of 36 shuttle flights is 52 billion US $. At the International Space Station, each person day cost is approximately $ 7.5 million ( 56.25 crores).
Assembly and Integration:
The International Space Station is such a giant structure that it was impossible to build it on Earth and then launch into space in one go because such a powerful rocket is still not available. So, the station was taken into space piece-by-piece and gradually built in orbit by astronauts and robotics. It took 10 years and more than 30 missions to assemble. NASA’s space shuttle was used to carry most of the heavier pieces, although some individual modules were launched on single use rockets.
The station is divided into two sections, the Russian Orbital Segment (ROS), which is operated by Russia and the United States Orbital Segment (USOS), which is shared by many nations.
The major structural components of the station can be grouped under two sections, pressurised and unpressurised. The pressurised sections are accessible by the crew without using spacesuits. While accessing the station’s unpressurised superstructure, space suits have to be used.
Challenges of Space Station:
Why is the installation and maintenance of the space station so challenging? The space environment is hostile to life. Unprotected presence in space is characterised by an intense radiation field, high vacuum, extreme temperatures and microgravity. Making a pressurized module where the astronauts can live in Earth-like conditions in space and then bring them back to Earth after the expedition are arduous tasks.
Any manned mission to space presents a massive technological challenge because there is absolutely no room for any error when the safety of astronauts is concerned.
It is imperative to master the following key technologies for the establishment of a space station:
Design of Pressurized Module
Construction of Heavy Lift Launch Vehicles
Environmental Control and Life Support System
Launch Escape System
Docking, Un-docking, Rendezvous
Atmospheric Re-Entry Capability
Space Suits and Parachutes
Waste Collection and Water Recovery System
In spite of the availability of immense scientific expertise and utmost precautions some setbacks and failures have been reported with the International Space Station:
Soyuz MS-10, a crewed spaceflight was aborted shortly before launch on October 11, 2018, due to a failure of the Soyuz launch vehicle boosters. The crew were later flown to the station on March 14, 2019, onboard Soyuz MS-12.
The Soyuz spacecraft carrying Russia’s first humanoid robot, Fedor, to Space Station failed to dock.
Recently, a space capsule, Starliner, built by Boeing and successfully launched by the NASA to ferry astronauts to ISS, failed to reach the designated orbit during its first test flight.
Indian Space Station:
India is not inclined to join the International Space Station, instead, it wants to establish its own space station. The success of the Gaganyaan project will act as a precursor to the space station project. As per the current plan, the 20-tonne station is expected to be placed in a low earth orbit of about 400 kilometres altitude and will be capable of harbouring three crew members for 15-20 days. The rough time-frame is five to seven years after completion of the Gaganyaan project. There will be no collaboration with any other country for this project. The Space Station likely to be used to conduct microgravity experiments.
India still has to master many technologies, like Launch Escape System, Re-entry and Recovery Techniques, Space Suit, Astronaut Training, Heavy Lift Launch Vehicles, Life Support Systems, Soft Landing, Docking, Un-docking, Rendezvous, etc.
The second and more challenging is budget mobilization. Many planned crew space stations have either been cancelled or converted to ISS primarily due to excessive costs. Besides, the direct benefits of these missions are not visible immediately and space missions are always risky.
An unmanned rocket, Antares that was carrying a Cygnus cargo ship to the station exploded a few seconds after take-off.