Nine months in space, on a mission that was supposed to last just eight days—NASA astronauts Sunita Williams and Butch Wilmore have finally returned to Earth. The duo left Earth in June 2024 to test Boeing's Starliner capsule, but due to technical issues, NASA decided to keep them on the International Space Station (ISS) and return the Starliner empty. Throughout the year, several space agencies and private companies also scheduled missions to resupply the space station with food, water and oxygen.
Williams and Wilmore are not the first astronauts to stay in space for an extended time due to unforeseen circumstances. The longest spaceflight by a U.S. astronaut was by Frank Rubio. He spent 371 days aboard the ISS from 2022 to 2023, which was prolonged due to problems with the Soyuz spacecraft that brought him to orbit.
NASA's William M. Shepherd, Russia's Yuri P. Gidzenko, and Sergei K. Krikalev were the first astronauts to board the ISS on November 2, 2000, for a four-month mission. Since then, humans have been in space uninterrupted, in small groups of six at a time.
But what is the International Space Station, and what is life like on it?
The ISS is a spacecraft, an observatory, a laboratory, and a home where astronauts carry out experiments on biology, technology, and other fields, with implications for life in space and on Earth. It is one of the brightest objects in the sky. In fact, you can spot the International Space Station with the naked eye.
The orbiting space laboratory is the result of decades of international effort. The ISS, built and operated by 15 countries including the United States, Russia, and Japan, began operations in 1998 as a base for all sorts of space-based research. It floats 240 miles above Earth's surface and completes 16 orbits of Earth every 24 hours, travelling through 16 sunrises and sunsets.
According to the National Aeronautics and Space Administration (NASA), ISS is larger than a six-bedroom house with six sleeping quarters, two bathrooms, a gym, and a 360-degree view bay window. Microgravity means that crew members face obstacles in all their daily routines, such as eating, sleeping, taking showers and more.
This weightless environment forces astronauts to rethink even the most basic aspects of daily life, including how they eat. The space station has no refrigeration, so all food must be stored carefully and is often vacuum-packed. Some foods are specially designed, like spaghetti, which requires added water. Even salt and pepper are in liquid form because, without gravity, the sprinkles would float away. Free-floating droplets of water can be hazardous on the ISS, as they could end up in sensitive equipment and cause malfunctions. In 2015, astronauts grew and ate their first space-grown salad. NASA says: “The Veggie concept is a simple, low-power system to grow fresh, nutritious food for our astronauts to supplement their diet and use as a tool to support relaxation and recreation.”
There are two space toilets on the ISS, which astronauts strap themselves into to use. Their urine is even filtered and turned into drinking water.
Weightlessness also takes a physical toll. On Earth, even when you stand still, your muscles and bones resist gravity and help maintain posture. In space, however, your body doesn't need support from muscles and bones. If astronauts don't exercise, their muscles and bones will weaken. Therefore, they exercise for about two hours every day. They use resistance exercise equipment for weight training and aerobic exercise equipment like treadmills and ergometers. On the treadmill, astronauts can run while being held down by rubber straps.
Since gravity is very weak in space, water floats in every direction. Because of this, the ISS does not have baths, showers, or washstands. To clean their bodies, astronauts use a wet towel with body wash. For washing their hair, they apply waterless shampoo and wipe it off with a dry towel. To wash their hands or face, they use a wet wipe or a towel with liquid soap.
Then comes sleep, which, like everything else in space, requires adjustment. In space, there is no clear distinction between up and down as on Earth. Any surface can serve as a floor, wall, or ceiling, allowing astronauts to sleep anywhere. However, weak gravity means that astronauts may slowly float away while sleeping. To prevent this, most astronauts on the ISS sleep by securing their bodies in small sleeping compartments or sleeping bags. Also, due to the large amount of equipment on the ISS, the sound of air-conditioning fans and machinery is always present. Astronauts disturbed by these ambient noises and who have trouble sleeping may use eye masks and earplugs.
Because there isn’t an up or down in space, Astronauts often feel sick during the first few weeks on the ISS, and the body usually takes time to adjust. Living in space has been compared to standing on your head. With less gravity pressing down, fluids tend to accumulate in the upper parts of the body, causing astronauts to have puffy, red faces.
Each astronaut on the Space Shuttle has a specific role and receives intensive training for that task. In case of medical emergencies, the Crew Medical Officer is in charge. The medical officer is trained not only in basic first aid but also in procedures like stitching wounds and administering injections. All astronauts are trained for emergency resuscitations.
The ISS residents have laptops and can connect to the internet to keep in touch with family and friends. They share stories and photos via social media and also take part in educational sessions via video, discussing science and space with students around the world.
