The International Space Station (ISS) is one of the most iconic symbols of space exploration. Though the days of the space race and moon landings are now things of the past, this station remains an important and relevant part of modern science. With no foreseeable end in sight, the ISS will likely continue to be important, too.
The ISS has been in orbit for 20 years now. Space programs have come and gone, technology has evolved and governments have changed. Yet, this spacecraft still orbits Earth. So how have NASA and other space agencies kept it operational for so long?
Before asking how astronauts keep the ISS running, you may be wondering why they should do so.
The ISS represents a historic collaboration and is a landmark of technological progress. Beyond that, it’s an essential research tool. For all of its history, the space station has helped scientists understand our world and those beyond.
Several different countries, including the United States, Japan, Russia and Canada, came together to build the ISS. Construction began in 1998 when Russia launched the Zarya control module. Over the next two years, additional countries flew more pieces of the station into space until its first crew arrived in 2000.
The ISS isn’t just a symbol of international efforts, though. It’s a collection of laboratories, allowing scientists from all over the world to conduct experiments in conditions they couldn’t achieve on Earth. Some of these experiments revolve around space itself, but many of them explore properties of our home planet.
Research from the ISS has led to discoveries in areas like bone loss and vaccine development. The unique conditions aboard the station, such as microgravity, allow astronauts to develop a better understanding of the laws of physical reality. The ISS is vital to the sciences, so it’s vital that the ISS stays operational.
Perhaps the most crucial part of keeping the ISS operational is making sure people can live in it. A lab in outer space doesn’t do much good if you can’t stay inside it for long. Astronauts have to ensure the ISS provides safe living conditions.
The first necessity in sustaining a livable habitat in space is providing clean and breathable air. The atmosphere on Earth isn’t 100% oxygen, so astronauts need compressed air from Earth, not just pure oxygen. Spacecraft bring tanks of air to the ISS, and astronauts have to make sure their air compressors are clean and efficient to maintain the right balance of gasses.
Astronauts also use systems that draw oxygen from recycled water onboard the station. They split water into hydrogen and oxygen, using the oxygen in the ISS’s air system and expelling the hydrogen along with the carbon dioxide astronauts breathe out. The station also has tools that recycle drinking water so astronauts can stay hydrated at all times.
Another important part of keeping the ISS habitable is maintaining livable temperatures. Insulating materials line the ISS to keep out excessive temperatures, while equipment like heaters and liquid coolers keep a comfortable internal temperature. Astronauts have to check and repair these systems routinely to stay safe from the extreme temperatures of space.
Living conditions aren’t the only thing astronauts have to manage. The ISS’s value as a research tool depends on the quality of its equipment. Astronauts have to make sure their machinery is functioning correctly at all times.
You probably already know that the current equipment onboard the ISS isn’t the same stuff it had when it launched. Technology changes quite a bit over 20 years, so when astronauts come to the station, they bring new tech with them to replace older gear. For example, astronauts swapped the ISS’s old nickel-hydrogen batteries for more efficient lithium-ion ones in 2017.
To keep the power on, the ISS relies on renewable energy in the form of solar power. In space, the sun’s radiation is stronger, so the ISS’s solar panels have a constant, reliable power source. Using 27,000 square feet of solar panels, the ISS can provide plenty of electricity so all the equipment can run at full power.
The ISS uses Earth’s gravity to stay in orbit, but gravity could also pull it down into the atmosphere or at least slow it down. To avoid this, the ISS will occasionally ignite the engines on some of its attached spacecraft. These periodic boosts keep the station on its course so astronauts can continue their work uninterrupted.
Before they go to space, astronauts learn how to maintain the equipment they’ll be using. If something breaks, they’ll know how to fix it. However, preventing malfunctions is better than correcting them. To keep everything running for as long as possible, astronauts try to avoid damage to the station and its tools.
The ISS isn’t the only thing orbiting Earth, and running into debris could damage the station. The U.S. Air Force tracks larger pieces of debris so they can tell the ISS to adjust their course if necessary to avoid a collision. Astronomers around the world are also building new systems to help prevent collisions. The EOS Research Centre at Mount Stromolo Observatory is also using a telescope to track debris. The ISS also has a protective layer of shielding to defend against smaller, untrackable pieces of debris.
In low levels of gravity, dirt could float into sensitive equipment, causing it to malfunction or fail. To ensure the safety of their systems, astronauts continually clean and sanitize everything onboard with wipes and vacuums. To manage the junk and dirt they collect, astronauts put all their trash in sealed bags that they periodically send back to Earth.
Keeping the ISS fully functional isn’t an easy job, but it’s a necessary one. By taking these steps, astronauts ensure that the space station can continue to serve scientists from across the globe for years to come.