The International Space Station (ISS) is the largest structure humans have ever put into space. In fact, it's so large that it wasn’t launched in its entirety. It was sent up in pieces, and then constructed in orbit. The ISS is also estimated to be the most expensive man-made object ever built. Its hefty price tag exceeds $100 billion.
So, who uses the Space Station and for what? How big is it, and can we see it from down here on Earth? Let’s get to know the ISS.
What is the International Space Station used for?
A variety of scientific experiments are being conducted on the International Space Station every day. For starters, the ISS offers us a unique opportunity to view our planet from the outside. Astronauts at the space station conduct experiments that include things like aiding with storm forecasts and testing satellite technology.
Astronauts aboard ISS also perform particle physics experiments like using the Alpha Magnetic Spectrometer-02 to look for dark matter and antimatter particles without the background noise that would normally dampen such a signal down here on Earth.
Inhabitants of the space station also participate in studies of how the human body—including our muscles, bones, heart, and eyes—change without the presence of Earth’s full gravity. In NASA’s unique twin study, Astronaut Scott Kelly was studied for physiological, molecular, and cognitive changes during and after spending nearly a year in space in comparison to his retired astronaut identical twin brother Mark Kelly. Among the key findings of the twin study was the determination that our immune systems work in space just like they do on Earth. Astronaut Scott Kelly gave himself a flu vaccine while aboard the ISS and his immune system responded just as we would expect it to respond.
Astronauts also learn how to keep spacecraft functioning. They get to test out new technology for future space missions. These technological developments, combined with human biology studies, are our first steps toward the longer space missions which will be required for exploring other worlds. A trip to Mars, for example, would take at least three years round trip.
Astronauts and cosmonauts are also tasked with maintenance, including spacewalks to conduct repairs. To combat the bone density and muscle loss known to occur in microgravity, they also have to fit in at least two hours of exercise each day. You can check out Canadian astronaut Chris Hadfield’s series of videos about life on the ISS to get a look at what its like to brush your teeth, wring out a washcloth, make dessert, and even sleep in microgravity.