The crew aboard the International Space Station orbits Earth once every 90 minutes, traveling at roughly 28,000 km/h. But inside the station, life follows a surprisingly structured rhythm. Every crew member's day is planned in blocks, reviewed by Mission Control, and logged down to 5-minute increments. It is regimented, repetitive, and occasionally extraordinary.

Here is what a typical day actually looks like for the people living in space right now.

A Day on the Timeline

The ISS runs on Coordinated Universal Time (UTC), also known as GMT. This keeps operations synchronized between the station, NASA's Mission Control in Houston, and the other international partner control centers in Moscow, Munich, Tsukuba, and Montreal.

The crew day starts at 06:00 UTC with a wake-up alarm. There is no sunrise to set the mood (or rather, there are 16 of them per day). Instead, astronauts rely on the schedule uplinked to them the evening before. This timeline is managed by a team of flight controllers on the ground who plan every crew member's day in parallel, coordinating shared resources like equipment, lab space, and communication windows.

After waking up, astronauts go through a post-sleep routine: personal hygiene, changing clothes, and a quick breakfast. Brushing teeth in microgravity works about the way you would expect (toothpaste, toothbrush, a small amount of water), though most crew members swallow the toothpaste rather than try to spit into a floating blob of water.

By 07:30 UTC, the crew gathers for the Daily Planning Conference (DPC), a short call with Mission Control to review the day's schedule, flag any issues, and coordinate handoffs.

Morning: Exercise and Prep

Two hours of exercise every single day. That is not optional. It is one of the most important things astronauts do, and skipping it has real consequences.

In microgravity, the human body starts to break down quickly. Without the constant load of gravity pulling on bones and muscles, bone density drops at roughly 1% per month. Muscles atrophy. Cardiovascular fitness declines. Two hours of daily exercise is the primary countermeasure, and it is split between two types of training:

Astronauts typically split their exercise into two sessions, one in the morning and one later in the day, though the exact timing varies by crew member and schedule. The equipment is shared among the entire crew, so sessions are staggered.

Exercise is also one of the few parts of the day that astronauts say they genuinely look forward to. It is physical, unstructured compared to the rest of the timeline, and comes with a view. The COLBERT treadmill sits near a window.

The Work Day: Science and Maintenance

The core of each day is about 6.5 hours of scheduled work. This breaks down into two broad categories: science and maintenance.

Science

At any given time, hundreds of experiments are running aboard the ISS across disciplines including biology, physics, materials science, Earth observation, and human medicine. Some experiments are mostly automated and just need an astronaut to swap samples or check equipment. Others require hands-on time: growing protein crystals, tending plants in the Veggie growth chamber, drawing blood for medical studies, or monitoring combustion experiments in the glovebox.

Crew members receive detailed procedures for each experiment, often with step-by-step photo instructions sent up from the ground. For complex tasks, Mission Control can watch via onboard cameras and talk the astronaut through it in real time.

The science is the whole reason the station exists. Every other part of the schedule (the exercise, the maintenance, the logistics) is in service of keeping this research going.

Maintenance

The ISS is a machine the size of a football field, and it needs constant upkeep. On a given day, maintenance tasks might include:

Maintenance is not glamorous, but it keeps the station habitable. The ISS has been continuously occupied since November 2000, and some of its hardware is decades old. Things break. Workarounds become permanent. The crew has to be part scientist, part plumber, part electrician.

Meals in Microgravity

Astronauts eat three meals a day: breakfast, lunch, and dinner. The food comes pre-packaged in individual servings and falls into a few categories:

Tortillas are the bread of space. Regular bread produces crumbs, and crumbs in microgravity float into equipment, air vents, and eyes. Tortillas hold together, wrap around fillings, and do not create a maintenance problem. NASA has been flying tortillas since the 1980s, and they remain a staple.

Each crew member has a food container with their assigned meals, but they can trade items with crewmates. NASA also allows astronauts to request "bonus containers" of their favorite foods. These personal picks are a small but meaningful morale boost during a six-month stay.

The galley area has a food warmer and a hot water dispenser for rehydrating freeze-dried packets. There is no refrigerator (it would use too much power), so everything is shelf-stable.

Shared meals are one of the social anchors of station life. The crew gathers at the galley table, velcros their food pouches to the surface, and eats together. In a place where the work is highly individual and communication with the ground is constant, sitting down together for dinner is one of the few moments that feels genuinely communal.

Spacewalk Days

Most days follow the routine described above. Spacewalk days do not.

An EVA (extravehicular activity) is one of the most physically demanding and high-stakes tasks an astronaut can perform. Only about 10 happen per year, and each one requires weeks of preparation on the ground and aboard the station.

The day before a spacewalk, the two crew members assigned to the EVA begin a "campout" protocol. They sleep in the Quest airlock at reduced pressure to start flushing nitrogen from their bloodstream. This pre-breathe protocol is necessary to prevent decompression sickness when they transition to the lower-pressure suit environment (the EMU suits operate at about 4.3 psi, compared to the station's 14.7 psi).

On the morning of the walk, the astronauts put on their suits with help from a third crew member acting as the intravehicular (IV) officer. The IV officer runs the airlock systems, monitors suit telemetry, and coordinates with Mission Control while the spacewalkers are outside.

A typical EVA lasts 6 to 7 hours. Tasks range from replacing batteries on the station's solar arrays to installing new experiments on the exterior truss. The work is slow and precise. Gloved hands lose dexterity. Tools are tethered to prevent them from floating away. Every movement is planned and rehearsed, often months earlier in the Neutral Buoyancy Lab (a massive swimming pool in Houston used to simulate weightlessness).

After the walk, the crew repressurizes the airlock, removes the suits, and undergoes medical checks. Spacewalk days are exhausting. Most astronauts describe them as the hardest physical work they have ever done.

Evenings and Weekends

The workday nominally ends around 19:00 UTC. The crew has an evening planning conference with Mission Control to debrief the day and preview tomorrow's schedule. After that, the time is their own.

How astronauts spend their evenings varies. Common activities include:

See them fly over: While the crew runs through their packed daily schedule, the ISS passes over your location several times a day. Skytrail will tell you exactly when to look up, and knowing there are real people inside running experiments and exercising makes the sighting so much better.

Weekends have a lighter schedule. Saturday mornings are set aside for housekeeping: cleaning air vents, wiping down surfaces with disinfectant, vacuuming filters, and tidying the modules. The rest of Saturday and all of Sunday are mostly free.

From the Cupola, the crew can watch 16 sunrises and 16 sunsets every 24 hours. The station circles the globe roughly once every 90 minutes, so the scenery changes constantly. If you have ever wondered what the current crew might be doing at any given moment, there is a decent chance at least one of them is floating in the Cupola, watching the planet roll by below. You can even track the station's position overhead and know exactly which part of Earth they are flying over.

Sleep happens in small crew quarters, each about the size of a phone booth. Astronauts zip themselves into sleeping bags attached to the wall. There is no "lying down" in microgravity, so orientation does not matter. Most crew members say they sleep well once they get used to it, though the 16 daily sunrises can be disorienting. Window shades help.

Next time you see a bright dot crossing the sky at dusk, remember there are people inside doing all of this. I use Skytrail to know exactly when the station is passing over, and knowing the crew's daily schedule makes it feel much more real.