Life in space is vastly different from its depiction in science fiction movies. The International Space Station (ISS) lacks the comforts of home, with every liter of water and gram of cargo meticulously planned. This stems primarily from the challenges of microgravity and the staggering cost of orbital logistics.
We take a closer look at what a typical day involves for an astronaut living in orbit.
1. How do they wash? (Zero-gravity showering is a disaster)
The ISS does not have shower stalls. If an astronaut were to simply turn on a tap, surface tension would prevent the water from falling, causing it to cling to their skin in a thick, shimmering layer that could block airways and cause suffocation. Furthermore, stray water droplets drifting into the ventilation or electrical systems could easily cause a short circuit in critical equipment.
The hygiene process works as follows:
- Body: Astronauts use standard wet wipes along with specialized, no-rinse body gels. The gel is applied to the skin, rubbed in, and then simply wiped off with a towel.
- Hair: A similar no-rinse shampoo is utilized for hair care. It is massaged into the scalp and then dried with a towel.
- Shaving: Men use electric razors equipped with a dedicated vacuum attachment. This suction system collects hair clippings to prevent them from floating freely throughout the station.
- Teeth: Crew members use a standard toothbrush and toothpaste. The brush is moistened with just two or three drops of water from a drinking pouch. Since there is no rinsing, the foam is either swallowed—as the paste is safe to ingest—or spat into a paper napkin. The mouth and brush are then carefully wiped down with a tissue. These used tissues are not discarded loosely; they are sealed in waterproof bags along with other trash. After use, the brush is rinsed with one more drop of water, wiped, and placed back into its personal storage container.
2. How is laundry done? (A washing machine is an impossible luxury)
The short answer is: it isn't. There are no washing machines on the ISS. Water is far too heavy, and the cost of ferrying it into orbit is prohibitively expensive.
The fate of clothing: Astronauts wear their garments until they are visibly dirty or saturated with sweat. At that point, the items are sealed in airtight bags and placed in a waste container. When decommissioned cargo ships like Progress or Cygnus depart the station, this dirty laundry burns up along with the vessel in the dense layers of the atmosphere. Exception: NASA recently tested experimental bags that allow uniforms and socks to be soaked in a small amount of detergent, but this remains a trial. In 99% of cases, space clothing is strictly single-use.
3. Using the restroom (Powered by suction rather than gravity)
On Earth, gravity pulls waste down when a toilet is flushed. This principle does not work in space. A space toilet is essentially a high-powered vacuum cleaner fitted with a system of various funnels.
- Liquid waste: Astronauts use a specialized hose with a funnel attachment. Airflow literally sucks up the urine to prevent any of it from escaping into the cabin.
- Solid waste: The toilet seat features openings of varying sizes. The astronaut must be precise with their aim, or the consequences for the entire station would be unfortunate. Waste is deposited into individual bags that are automatically sealed and compressed by the airflow.
- Where does it go? Solid waste is packed into containers that burn up in the atmosphere with the rest of the trash. Urine, however, is sent to a regeneration system for a complex purification process.
What is the final result?
The end product of this multi-stage system is chemically pure distilled water. This water is then transferred to the station’s main buffer tank and integrated into the closed-loop life support system.
4. With all that water consumed, are there tons of it on board?
No, there are not tons of water stored on the station. Here is why.
Launching a single kilogram of cargo to the ISS costs between $2,000 and $5,000 depending on the launch vehicle. An astronaut needs about 2 to 3 liters of drinking water daily, in addition to water for food prep and air humidification. Annually, a six-person crew consumes around 5 to 6 tons of water. Transporting that volume from Earth would mean spending tens of millions of dollars on water alone.
So where does the water come from? Everything! The ISS uses a closed-loop life support system (ECLSS) that is a true engineering marvel. It recycles moisture with an efficiency rate of approximately 98%.
1. Urine: A specialized centrifuge separates water from the urine. After intensive chemical and thermal purification, including treatment in a reactor with zinc oxide and silver ions, it becomes crystal clear.
2. Sweat and breath: Humans naturally sweat and exhale moist air. The air conditioning system harvests this condensate directly from the station's atmosphere.
3. Hygiene: Any moisture remaining on wet wipes and towels is also recovered by the system.
All of this collected fluid passes through multi-stage filters and mineralizers before being disinfected with iodine. This water is primarily used for critical technical requirements:
- Oxygen generation: Distilled water is fed into electrolysis systems. An electric current splits the water molecules, providing the crew with pure oxygen to breathe.
- Technical systems: The water maintains cooling systems, humidifies the air, and supports other internal engineering operations.
The bottom line: Astronauts drink water that is far purer than any bottled water found on Earth. As the crew often jokes: “Yesterday’s coffee is today’s coffee.”
While astronauts drink the same amount of water as people on Earth, they do not store it in massive tanks. They constantly create it from their own waste, turning life in space into the most advanced recycling system known to man.
5. What do they eat? (The ban on bread)
Space food has long evolved past simple purees in tubes. Today’s menu features hundreds of items, including soups, stews, meat, fish, desserts, and even fresh fruit, though the latter is usually eaten within the first few days of delivery.
The number one rule of the space kitchen: no crumbs! While a breadcrumb on Earth falls to the table, in zero-G it floats throughout the module. Crumbs can get into an astronaut's eyes or, even worse, clog ventilation filters and damage equipment. Consequently, astronauts swap bread for tortillas. These can be used for sandwiches without crumbling.
Food is supplied in two primary forms:
1. Thermostabilized (in flexible pouches, similar to baby food or military MREs).
2. Lyophilized (freeze-dried). Before eating, hot water is injected into the pouch through a specialized port using a syringe.
Condiments like salt, pepper, and sauces are provided as liquids in small sachets, since dry powders would simply drift away into the air.
6. Sleeping in zero-G (and how not to drift away)
In weightlessness, the body floats freely, so simply lying in a bed is impossible. Overnight, an astronaut might drift into another module or collide with sensitive gear.
The ISS sleep station
Each crew member has a private cabin roughly the size of a phone booth. Inside, you will find:
- A sleeping bag attached to the wall, which can be oriented vertically, horizontally, or even upside down.
- A small desk area with a laptop.
- Personal belongings such as family photos, headphones, and books.
- A ventilation vent, which prevents exhaled carbon dioxide from pooling around the sleeper's head and causing suffocation.
How do they anchor themselves?
1. They climb into the sleeping bag and zip it up.
2. They strap the bag securely to the cabin wall or ceiling.
3. The arms are either tucked inside or left out; some astronauts prefer letting their arms float freely, which looks quite strange.
4. The head is often secured with a strap to keep it from bobbing and interrupting sleep.
Sleep specifics in space
- Pillows are unnecessary since the head does not press against any surface.
- They sleep for 7 to 8 hours, just like on Earth.
- They still dream, though many report that dreams are more vivid and unusual due to the lack of gravity.
- Noise is constant, with a 60 dB hum from equipment requiring everyone to wear earplugs.
- Because the ISS sees 16 sunrises and sunsets daily, portholes are covered with shades at night.
Astronaut testimonials
Many report that sleeping in zero-G is actually more comfortable than sleeping on Earth:
- There is no pressure on the spine or joints.
- The entire body is completely relaxed.
- Tossing and turning is unnecessary, as a simple arm movement is enough to shift positions.
There are drawbacks, however: a persistent sensation of falling as the brain interprets weightlessness as freefall, and the unending roar of the ventilation.
7. Exercise in orbit is more than just staying in shape; it is a biological necessity. In microgravity, muscles and bones are no longer subjected to normal loads. Without training, an astronaut would rapidly lose muscle mass and bone density, leaving them unable to stand or walk upon returning to Earth.
To combat this, the International Space Station (ISS) crew spends about 2 to 2.5 hours exercising every day.
Here is how the training process works and the equipment they use:
1. The three primary machines
With weight being non-existent in space, traditional dumbbells and barbells are useless. Engineers had to design specialized equipment instead:
- T2 Treadmill (COLBERT): Running in weightlessness is impossible, as one push-off would send you to the ceiling. Instead, astronauts wear a specialized harness that uses bungee cords to pull them toward the belt, simulating body weight. The treadmill is also suspended on a system of springs and dampers so that vibrations from running do not shake the station or disrupt sensitive experiments.
- ARED (Advanced Resistive Exercise Device): This complex machine simulates weightlifting using vacuum cylinders and flywheels. It creates resistance adjustable from tens to hundreds of kilograms. It allows astronauts to perform squats, deadlifts, and presses, providing the axial loading essential for maintaining bone density.
2. Training peculiarities
Exercise in space is vastly different from Earthly workouts due to the physics of zero gravity:
- The Sweat Problem: On Earth, sweat drips down or evaporates. In space, without convection, sweat pools into large, sticky globs that cling to skin and eyes. Astronauts must wear ventilated suits or constantly wipe themselves down with towels.
- Hygiene and Safety: Equipment is wiped with antiseptic cloths after every session. Stray sweat droplets could harbor bacteria in the closed environment or cause electrical shorts if they drift into the ventilation or electronics.
Standard ISS expeditions:
A typical mission lasts about 6 months (180 days). This is the baseline duration for most crew members. The world record for a single continuous flight is held by Valery Polyakov, who spent 437 days aboard the Mir station from 1994 to 1995. This means astronauts endure these Spartan conditions for months on end, not just a few days.
The central paradox of space life: the further humanity ventures from Earth, the more it must rely on its own waste. An astronaut in orbit is more than just a researcher; they are a vital link in the most efficient closed-loop system in existence. As the saying goes: “Yesterday’s tea is today’s oxygen.”
