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As the ISS turns 25, a look back at the space laboratory's legacy
By Conor Feehly published 1 day ago
The ISS just celebrated its 25th anniversary — soon, the station will be
hanging up its boots.

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international space station seen through a spacecraft window
international space station seen through a spacecraft window (Image
credit: NASA)
Hurtling through space at 17,500 miles per hour, the International Space
Station (ISS) circles the entire globe roughly once every 90 minutes —
which amounts to 16 sunrises and sunsets every 24 hours. At any point in
time, the station is home to no less than seven international crew
members, with the station's living and working areas amounting to the
size of an average six-bedroom house.

The ISS has undoubtedly become an iconic piece of human history, and on
Nov. 20, NASA celebrated the station turning 25. This anniversary in
particular feels a little bittersweet because the station itself is set
to be decommissioned by 2030, as the structure will become too fatigued
around then to be able to house astronauts safely. So, with an
expiration date being placed on humanity's foothold in space, it's worth
talking about what we've learned and why it matters.

Related: Quantum chemistry experiment on ISS creates exotic 5th state of
matter

In an obvious way, the ISS has been pivotal in the development of space
hardware. For engineers, the station has provided the unprecedented
challenge of creating a habitat in low Earth orbit that can safely host
a semi-permanent population of people. Microgravity conditions, the
threat of space debris collisions and harmful cosmic radiation also
create a novel environment in which scientists had to solve logistical
problems.

And because of those solutions, the ISS has provided an opportunity for
humans to test new technologies that could one day be used during
longer, farther crewed ventures to other areas in the solar system and
perhaps even deep space. But while the ISS has clearly been a source of
technological innovation, maybe more importantly, it has allowed us to
understand how being in space affects people.

The human body evolved on the surface of the Earth, so it's built to
stay on Earth. Space presents a new set of challenges. For example,
astronauts on the ISS have to spend two hours a day exercising to stave
off muscular atrophy, as their bodies do not have to continually work
against gravity on the surface of the planet thereby deteriorating their
strength.

"From the ISS programme, NASA has learned really what happens to the
human body in zero-G over long duration flights. When we go to Mars
we'll be committing those people to a long duration mission, so it's
imperative to know what that's going to do to their bodies," Brain
Ferry, commercial crew programme mission manager at NASA, said in a
statement.

Living on the ISS also presents a number of psychological challenges for
astronauts. Isolation, a lack of privacy, and a high expectation working
environment can all contribute to quite difficult working conditions.
Studying the psychological effects of living and working in space on the
ISS has helped researchers understand what people will need to thrive on
longer voyages into deep space.

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views

At the eventual conclusion of the ISS programme, the station will be
"deorbited" in a controlled manner, where the entire station's
facilities will break up and vaporize as the units enter Earth's
atmosphere. Any possible remnants of the station that reach the Earth's
surface will land in a remote part of the ocean.

Over the course of its lifetime, thousands of engineers, computer
scientists, researchers and astronauts from all corners of the world
have all contributed to the functioning and flourishing of the ISS. This
station, in a sense, therefore transcends scientific achievement. It
serves as an important symbol of what can be achieved when countries put
aside their differences and work towards a common goal.

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Conor Feehly
Conor Feehly
Contributing Writer
Conor Feehly is a New Zealand-based science writer. He has earned a
master's in science communication from the University of Otago, Dunedin.
His writing has appeared in Cosmos Magazine, Discover Magazine and
ScienceAlert. His writing largely covers topics relating to neuroscience
and psychology, although he also enjoys writing about a number of
scientific subjects ranging from astrophysics to archaeology.