On 20 November, 2018, the International Space Station marked the 20th anniversary of the launch of the station's first component, made possible by the contribution of hundreds of engineers, space shuttle astronauts, international support and the crews who continue launching up to this day. Since 2 November, 2000, the ISS has been continuously occupied.
Gary Oleson, a station engineer, told Space.com that the ISS had pushed NASA into “an entirely new way of thinking”.
Oleson has experience in the industry having worked for NASA’s Space Station Program Office from 1988 to 1993. Speaking of the unique characteristics of the ISS, Oleson said, "We normally think of a spacecraft as being a spacecraft. But it turned out that the International Space Station, during the assembly, was not, from an engineering point of view, one spacecraft. It was at one time 19 different spacecraft, because every time you went up and added a new element, you had a different spacecraft. It had a different mass; it had a different reliability."
The ISS is a habitable artificial satellite in the low earth orbit with its first component launch in 1998 and it’s first long term residents arriving in November 2000.
The ISS programme is a joint venture between five space agencies – NASA, Roscosmos (Russia), JAXA (Japan), CSA (China) and the European Space Agency (ESA). The ISS is the largest human-made body in low Earth orbit and can often be seen with the naked eye from Earth. It is still a station whose development and assembly continues to this day with components scheduled for launch even in 2019.
The ISS serves as a micro-gravity and space environment research laboratory, in which crew members conduct experiments in biology, human biology, physics, astronomy, meteorology, and other fields.
The station is also the stage for testing of equipment and whether or not they are suitable for missions to the moon and Mars. Some of the research over the last two decades has come across a spectrum of fields.
The Alpha Magnetic Spectrometer (AMS) on the ISS was used to detect hints of dark matter in 2013 – a finding NASA described as “an unexplained excess of high-energy positrons in Earth-bound cosmic rays."
Medical conditions have been under investigation and the most significant among these is the Advanced Diagnostic Ultrasound in Micro-gravity study, which lets astronauts perform ultrasound scans under the guidance of remote experts. The study considers the diagnosis and treatment of medical conditions in space. It is anticipated that remotely guided ultrasound scans will have applications on Earth in emergency and rural care situations where access to a trained physician is difficult – especially in third world countries.
Survival of some simple forms of life – called extremophiles and tardigrades – through a method called desiccation is also being studied as part of the scientific experiments in ISS.
In recent years, the ISS has also expanded to include cultural and educational outreach to the community. The ISS crew provides opportunities for students on Earth by running student-developed experiments, making educational demonstrations, allowing for student participation in classroom versions of ISS experiments, and directly engaging students using radio, video-link and email.
The future of the ISS is to build on the work that has already been done, but in view of how it is subject to harsh physical conditions which could affect the way the ISS itself functions, there are plans to end the mission in the coming decade.
While initially, plans were to dismantle the ISS by 2024, there recently has emerged a possibility that the mission could be extended up to 2028. However, whether or not there will be a replacement mission and if so, which countries would be willing to involve themselves remains a question to be answered. Russia seems eager to do it while the United States is not so much in support of launching another space station to replace the ISS. Whatever the road forward is for the ISS, there is no doubt that it has left a lasting legacy in the history of not just astronomy, but of the world as well.