What 20 years of space station research means for life on Earth

The International Space Station (ISS) is not just a place to live in space – it’s an experimental laboratory. With astronauts onboard and Earth positioned below, the ISS offers a unique opportunity: long-duration research in microgravity.

It also provides low Earth orbit views of our planet, along with a human crew who support experiments, swap samples, and troubleshoot in real time.

Since its launch, researchers have used the space station to conduct hundreds of studies. These range from characterizing fluid behavior in zero gravity to tracking changes in the human body. Their work advances science by answering questions that can’t be studied on Earth.

Science without gravity

Without Earth’s gravity pulling things down, scientists can run experiments that simply aren’t possible on the ground. For example, hot air doesn’t rise. Flames take on a spherical shape. Fluids stop behaving the way they do in a glass of water.

This gives researchers a rare opportunity to examine physical, chemical, and biological processes in new ways.

By eliminating variables like surface tension or capillary movement, they can get a much clearer picture of how things actually work.

Orbiting lab sees it all

The space station orbits Earth in about 90 minutes, traveling at 17,500 miles per hour from about 250 miles above the surface.

This low vantage point means the ISS is able to make observations of the planet both in daylight and darkness, and from various angles and lighting conditions.

By being outside Earth’s atmosphere and magnetic field, the ISS carries instruments that could not be used on Earth.

That makes it possible to study space radiation, neutron stars, and other phenomena – along with how materials and living organisms behave in space.

ISS crew makes science possible

Other satellites can carry instruments, but only the ISS has a living, breathing crew to run the science. Human operators are key. They adjust setups, monitor changes, fix problems, and pack samples for return to Earth.

This flexibility is critical for complex research on the ISS. It also means scientists can get a second chance if something doesn’t go as planned.

Since experiments can stay on the station for months or even years, there’s plenty of time to refine ideas and gather more data.

Body changes in space

Because the space station has been operating for over two decades, scientists have been able to track long-term changes – including how space affects the human body. One example: vision changes that astronauts began noticing after spending months in orbit.

Scientists launched the Fluid Shifts investigation in 2015 to understand what was happening. They suspected that in microgravity, fluids move from the lower to the upper body, increasing pressure in the head and possibly changing eye shape.

The study asked whether increased fluid pressure was the cause of these vision changes.

It ran through 2020 and tracked multiple astronauts over time. It marked a major step toward understanding the effects of spaceflight on human health.

Research on the space station

Research on the space station takes time. First, scientists have to identify a question and come up with a possible answer. Then, they design an experiment to test it, decide what data to collect, and figure out how.

Getting that experiment into space is its own process. NASA reviews proposals based on scientific value and relevance.

Once approved, studies are scheduled for future missions – often many months away. Training, hardware development, flight procedures, and data collection plans all need to be worked out.

Once the experiment is on board, astronauts begin collecting data. After that, the real work begins: analyzing results and writing them up. That alone can take a year or more.

Before a study is published, it goes through peer review. One analysis found that peer review alone takes an average of 100 days. Editors may also ask for revisions or more analysis before giving the green light.

Small crew, big science

One challenge with human research on the International Space Station is the limited number of subjects. With only about six people on board at any given time, gathering enough data takes longer.

Consider the Lighting Effects study, which tested whether adjusting the station’s lighting could improve sleep, mood, and performance by syncing with astronauts’ circadian rhythms.

Because researchers needed data from several astronauts, the study ran from 2016 to 2020. Other long-term human studies have looked at heart muscle loss and nutrition, including how to grow fresh food in space.

Space station research takes time

Research in physical science can often move more quickly. Scientists can send up batches of materials and collect results faster. But even then, one round of experiments often leads to more questions.

The Burning and Suppression of Solids (BASS) series ran from 2011 to 2017, studying how different fuels behave in space. That work led to the Saffire series, which began in 2016 and ended in 2024.

These fire safety demonstrations helped answer critical questions about how to prevent and put out fires in space.

Scientific breakthroughs don’t happen overnight, especially not in orbit. But the space station gives researchers something priceless: time, access, and the ability to keep going.

The payoff? New insights into how our bodies work, how materials behave, and how we can prepare for longer missions. That’s not just useful for life in space – it helps improve life back on Earth, too.

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