ISS: The International Space Station

Just recently, NASA revealed that the ISS is scheduled to retire in 2031. It will be crashing down into the South Pacific ocean (far away from the nearest habitation). What has that ISS ever done for us?

The International Space Station (ISS) is a spacecraft which is located in the low orbit Earth. It can be described as a manned spacecraft kept in a fixed orbit at a relatively low altitude (a space station). A space station is a type of satellite that is capable of accommodating a crew of humans or any other form of life for an ample period. Space stations orbit around planets, collecting and analysing data, and conducting investigations on the space environment. 

ISS originated as a result of a multinational partnership to design a productive space station. The Soviet Union had earlier succeeded in launching two spacecraft. The ISS was prompted when NASA had drawbacks in funding a national space station and consequently proposed a coalition with other developed countries. Russia gave in, deciding to couple their space station with that of the US. Several countries in Europe and Japan joined in and this resulted in the International Space Station.

The nations involved in the program include:

1. United States (NASA)

2. Russia

3. Japan

4. Canada

5. United kingdom

6. Several European Union states: Switzerland, Belgium, Italy, Switzerland, Denmark, France, Germany, Netherlands, Sweden, Spain, and Norway. These states together with the UK form the European Space Agency (ESA).

The ISS was launched on 20 November 1998. Human presence in the spacecraft began two years later. It is located at the low orbit of the Earth at about 350-450 km from the Earth surface (sea level). The period of revolution around the Earth is about 92 minutes. This means that the satellite revolves around 15 times in an earth day. The ISS is maintained at standard atmospheric pressure (1 atm or 1 bar). 

Structure of ISS

The ISS is a modular satellite. This means that it is made up of several detachable components. The ISS was assembled slowly by coupling new modules introduced by space shuttles or rockets. The component modules are constructed in different regions in the world and finally coupled together in orbit by astronauts. There are presently 16 modules constituting the ISS. These modules serve various purposes such as being laboratories for onboard experiments, power generation and management systems, data processing, transportation and delivery of cargos and other machines, and even the space crew.

ISS can be visible from Earth at night as it is a very good reflector of light from the moon. It is located in the thermospheric region of the atmosphere and is protected by the Earth's magnetosphere. Earth's magnetic field extends to just less than a hundred thousand kilometres away. This is very important as it helps deflect solar radiation which can destroy spacecraft. Scientists living in ISS are in continual communication with those on Earth, sharing data, current situations and information.

Scientific Research on the International Space Station

1. Missions and spaceflight to Mars and other extraterrestrial planets

The microgravity environment of ISS has facilitated studies of conditions outside our planet. A lot of information has been obtained concerning the possibilities and the implications of colonization of celestial bodies such as moons and planet Mars. For a long time, humans have been enthusiastic about establishing our existence on other planets. The gravity on Mars has a value of approximately 3.7m/s². This is 2.6 times smaller than that of the Earth (9.8m/s²). This would certainly require heavy adjustments in human physiology to be able to adapt to the environment of Mars.

2. Astrophysics 

ISS's Alpha Magnetic Spectrometer (AMS) has been a powerful tool for the study of astronomical particles especially the investigation of the nature and origin of dark matter particles. It is estimated that > 95% of matter in space is composed of dark matter. The remainder is a common matter. It has been revealed that particles such as positrons are generated by the annihilation of dark matter particles through the detection of cosmic-ray positron creation. This achievement by the ISS is a considerable step towards understanding the nature of mass in the universe.

3. Meteorology

 the ISS has allowed for active studies of the atmosphere and related conditions. Located within the Earth's thermosphere, ISS has allowed studies of solar radiation and particles, temperature, ozone levels, cloud formation, lightning, e.t.c and how they can affect climatic conditions on Earth.

4. Biomedical research and investigations

 Physiology on Earth varies significantly from that in space. Blood circulation, tissue formation and organization, nutrition psychological and tumorigenesis are critical concerns regarding long-term exposure to outer space. Due to gravitational impacts on several biological functions, it is indispensable to determine the effects of living in outside space if leaving Earth is to become a reality. Organs and tissues are constantly being examined on ISS to study the effect of low gravity and the vacuum of space on human development. Radiation is a primary problem confronting life. If we must set out to Mars or any other habitable planet, we must be able to survive these rays.

5. Space agriculture

Space farming is becoming an active area of research. This involves growing crops on other planets or satellites (natural or artificial). It is expensive to deliver food to space crew by use of rockets. For long-duration missions like the mission to Mars, large quantities of food and other nutriments must be supplied, replenished and adequately stored. Even for scientists living in ISS, feeding remains a challenge. ISS simulates conditions that should be met before a sustainable agricultural system and nutritional independence can be attained. Plants require sufficient water, sincerity, pressure, e.t.c. to grow and produce.  Microgravity, light intensity, water balance, atmospheric pressure and availability of nutrients are important factors that determine the possibility of a sustainable mission. 

6. Space biology

Do you know that microorganisms have been identified in space? Several species of bacteria were recently discovered some of which were previously unknown to biologists. The study which was published in Frontier of Microbiology states that four species of the Methylobacteriaceae family of bacteria have been found on board. Could they have been introduced by humans or did they get attached to the space station from outer space?

Many other multicellular organisms have been introduced into space. They include rodents, arachnids and tardigrades. This is to study the effects of ionizing radiation, microgravity and vacuum on adaptation and survival. The identification of new species of bacteria offers more evidence to the panspermia hypothesis which suggests that life on Earth were a result of the introduction of extraterrestrial organisms which proliferated to give the diverse life forms present today. Microorganisms in space could enable success in building a space farm as there are mutualistic relationships between plants and microbes which can benefit plant growth.

What is the value of the ISS?

ISS is a multibillion-dollar project funded by contributions from the various nations involved. The countries are listed above. Its operational cost is said to be $4 billion per year. It is consequently the most expensive megastructure ever built.

The future of space expeditions: outlook and hurdles

Scientists have discussed a lot about landing on Mars and possibly colonizing it. We can safely conclude that it is not feasible to get to Mars now with current technology. A trip to Mars could be considered a 'dangerous adventure'. There are lots of asteroids and space debris that could interfere and collide with spaceships and/or rockets. The distance between Earth and Mars is in the order of several hundred million kilometres. The distance between Earth and our moon in comparison is just 384 thousand kilometres. This means that even with the fastest spaceship currently available, it would take several or years to get there on a continuous journey. Consider the expenditures on construction, fuel and operations. That would indeed be prohibitive.

The ISS or any of its modules is not designed for missions to Mars or interplanetary travel. None of the components is capable of attaining the necessary velocity or withstanding the amount of cosmic radiation present outside of the Earth's field. But the space stations allows us to study the effects of decreased atmospheric pressure, microgravity, and even material stability in planets like Mars.

What are the plans by space agencies to successfully and sustainably send humans to Mars? More about human missions to Mars would be explained in my next article on "Mars".