It is no exaggeration to say that the world's most exciting research centre is in space. For more than two decades, the International Space Station has been contributing to our understanding of space, its characteristics, and the behaviour of living beings in space.
The ISS is operated in low Earth orbit and circles the Earth every 92 minutes, or 16 times in a single day. It is home for up to months to a crew of 6 astronauts and scientists who carry out scientific work in space. This is a huge and unprecedented task in the history of mankind. The research base, the result of an international collaboration, has given society many new developments and plans, and the private sector a major boost, proving that space is the future and that, with the democratisation of technological development, anyone with the right knowledge can enter this exciting new market.
The ISS is the result of an international collaboration. Many countries are involved in the project: the European Space Agency (ESA) Member States, the United States, Russia, Canada, Japan, and Brazil.
In the following, we will look at the history, operation, and future of the International Space Station.
History of the International Space Station
The ISS was built over many years from modules. The first of them, Zarya, was launched on 20 November 1998, and shortly afterwards, on 4 December, the Unity module was joined by the Endeavour space shuttle. The latter was a connecting node allowing docking of other modules.
The first habitation module, Zvezda, joined the two modules in July 2000. That year, the Z1 lattice module was installed, followed at the end of the year by the associated P6 lattice module with a solar panel module. On 2 November 2000, the first crew arrived at the space station: the American astronaut William McMichael Shepherd, and the Russian Yuri Pavlovich Gidzenko and Sergei Konstantinovich Krikalyov. From that year onwards, the space station was inhabited, with a crew of at least two.
Shortly after the arrival of the first astronauts, the first research module, Destiny, was attached to the station in February 2001. The Canadians sent up the SSRMS robotic arm in April and the Quest airlock module was attached to Unity in July. The latter is used as a base for launching and waiting for astronauts and researchers during space missions. The Russians launched the Pirs airlock module, which was attached to Zvezda, for the same purpose.
In 2003, the tragedy of the space shuttle Columbia set back the development of the station. Due to the US flight stop, the Soyuz crew vehicles and the unmanned Progress resupply spacecraft were used to supply the crew on board.
The construction of the space station continued in 2006, with the installation of the P3/P4 elements, the solar panels and then the P5 grid element. In the following years, the S3/S4 and S5 elements were connected to the station. The ISS thermal control and electrical systems were thus completed.
As the years went by, more and more researchers wanted to go up and do research in the microgravity environment. The living quarters were further expanded with the Harmony node module, which was connected to Destiny.
European research is centred on Columbus, which was connected in February 2008, followed immediately in March by a storage module, the Canadian Dextre robotic arm manipulator and the first elements of the Japanese Kibo. Several more flights were carried out during the year, during which additional elements of the space station were attached.
The space station was completed in 2011 and consisted of 16 pressurised modules, solar panels and other structural elements.
Since then, numerous additional modules were added, such as the ESA-built observatory module Cupola, the multipurpose laboratory module-upgrade (Nauka) and the Prichal nodal module.
ISS structure and operation
As we saw, the ISS is made up of various modules and lattice structures. It has a volume of almost 1000 cubic metres, a length of 108.4 metres and a weight of 420 tonnes. The huge complex can generate 100 kW of power. But how?
It harnesses the sun's energy through solar panels to generate electricity. As the space station orbits the Earth 16 times a day, it spends part of its time in a shaded area. During this time, it uses the energy stored in its batteries.
Russian solar panels mounted on the Zarya and Zvezda modules can produce 32 volts. The former contains 6 and the latter 8 nickel-cadmium batteries. The batteries of the Zarya module have been assembled, after which the Russian modules will rely in part on the US for their power supply.
The Americans have placed the solar panels on grid structures: the S4, P4, S6, P6 grid panels all carry solar cells. They are moved and rotated by SARJ rotating units and turned continuously towards the sun for the best energy supply.
Life on the ISS
The space station has a so-called life-support system, which is responsible for ensuring that life-supporting conditions are maintained on the station. It ensures, for example, that the air composition is right, that humidity and pressure are within the required limits and that waste and water are properly managed.
On the space station, the air in the habitable units is like on Earth. Nitrogen must be transported to the space station in tanks. The Electron and OSG facilities produce oxygen and hydrogen from water by electrolysis. The latter is released into space and the former is used as a by-product.
There are also safety solutions to provide oxygen. For example, there are oxygen generating candles that can produce enough oxygen for three people for up to two months.
One may wonder what happens to the carbon dioxide exhaled. These are removed by molecular filters in the Vozduh and CDRA facilities and then released into space. There are also emergency activation solutions. For example, lithium hydroxide filters are provided by the Russian unit.
Water arrives at the ISS in sealed containers containing all the minerals that are found in potable water on Earth. Developments in this area have been very active. As a result, in 2008 the WRS unit was put into operation, which produces pure water by distilling and purifying the vapour extracted from the space station's atmosphere and the urine produced by the astronauts.
What research is being done on the space station?
The main purpose of the ISS is to carry out research in a microgravity environment and to observe space and the Earth. Over the past two decades, more than three thousand research missions have been carried out on this unique research station.
These studies have touched on a wide range of disciplines, such as biology, geography, physics, and chemistry. The research operations investigated a wide variety of questions. Many of them focus on how human beings and organisms behave in space, but some investigate changes in the Earth, its properties, or even black holes.
Although many people do not think that the scientific significance of the research carried out on the space station is as significant as we might think, it must be said that the station has produced some ground-breaking results in terms of curing diseases and existing in microgravity. Not to mention the fact that the real usefulness of the research will only become apparent in the future, as space research and space industry developments are expected to become increasingly important.
And this right leads to the question: what will happen to the International Space Station when the private sector comes on board?
What does the future hold for the space station?
According to a recent NASA proposal, the future should see a shift towards the operation of privately owned space assets. The ISS programme is expected to end around 2030, which means that it will be able to operate and perform its current function until 2028.
Decommissioning will be necessary because the structure is quite old, with an increasing number of failures, which are costly. Not to mention the fact that the programme is already well overrun, as it was originally planned to maintain the space station until 2016.
It is predicted that by the 2030 target date, the private sector will be strong enough to build similar or more advanced stations. Industrial players will be able to organise independent projects and experiments to support their products and services. Currently, NASA has contracts with 3 commercial companies to build space-based research stations: Blue Origin, Nanoracks LLC and Northrop Grumman.