The International Space Station | Learn About Life In Orbit

The International Space Station has been continuously inhabited since the year 2000, serving as a laboratory, home, and engineering marvel orbiting hundreds of miles above Earth. This episode explores the station’s purpose, the international partnership behind it, how astronauts live and work in microgravity, and the research conducted aboard the station.

It’s steady and consistent, with no whispering and no sudden changes, just enough to give your mind something to follow as you wind down. Happy sleeping!

Transcript

Welcome to the I Can't Sleep Podcast, Where I help you drift off one fact at a time. I'm your host Benjamin Boster and today's episode is about the International Space Station. The International Space Station, ISS, Is a space station in low Earth orbit, LEO. It is a product of the International Space Station Program and is operated by five partner space agencies. NASA, United States, Roscosmos, Russia, ESA, Europe, JAXA, Japan, NCSA, Canada. It is the first space station built, Maintained, And crewed through international cooperation, And the largest human spacecraft ever constructed. It is an orbital research station where scientific experiments in microgravity are conducted and the space environment is studied. Since November 2, 2000, It has hosted the longest continuous presence of humans in space. Alongside Tiangong, It is one of the only two currently operational space stations. The station orbits between 51. 64 degrees north and south at about 400 kilometers above Earth below the Van Allen radiation belts and most space debris. Its orbit takes it at 7. 67 km per second, Roughly every 93 minutes around Earth, 15. 5 times a day. Measuring 109 m x 73 m, It is as large as a full-size football or soccer field and has a pressurized internal volume of 1, 005 m³, Comparable to a Boeing 747 airliner. The station is a modular space station divided into two main sections. The Russian orbital segment, ROS, Developed by Roscosmos, And the US orbital segment, USOS, Built by NASA, ESA, JAXA, And CSA. The integrated truss structure connects the station's vast system of solar panels and radiators to its 16 major pressurized modules. These modules support scientific research, Crew habitation, Storage, Spacecraft control, And airlock operations. The ISS has eight docking and berthing ports for visiting spacecraft. In total, The station consists of 43 different modules and elements. Cruise visit via the Soyuz and Crew Dragon spacecraft, And previously the Space Shuttle. Cargo supply craft include Progress, Cargo Dragon, Cygnus, Automated Transfer Vehicle, And HTV-X. The ISS is the political product of the development of international cooperation in space throughout the space age. The station combines two previously planned crewed Earth orbiting stations, The United States Space Station Freedom and the Soviet Union's Mir-2. The first ISS module was launched in 1998, With major components delivered by Proton, Soyuz, And Space Shuttle launch vehicles. Long-term occupancy began with the arrival of the Expedition 1 crew on November 2, 2000. Since then, The ISS has remained continuously inhabited for 25 years and 249 days, The longest continuous human presence in space. As of August 2025, 290 individuals from 26 countries had visited the station. Future plans for the ISS include the addition of at least one module, The Payload Power Thermal Module by Axiom Space, Forming the commercial segment of the station. The station is expected to remain operational until the end of 2030, By which parts of it are to be used for Axiom Station and the Russian Orbital Service Station. After this, The ISS is planned to be de-orbited using the U. S. De-Orbit Vehicle. But critique of this plan and the proposal of parking the station at a more stable, Higher orbit has gathered Congressional support as of 2026. The ISS was originally intended to be a laboratory, Observatory, And factory, While providing transportation, Maintenance, And a low-Earth-orbit staging base for possible future missions to the Moon, Mars, And asteroids. However, Not all of the uses envisioned in the initial memorandum of understanding between NASA and Roscosmos have been realized. And the 2010 United States National Space Policy, The ISS was given additional roles of serving commercial, Diplomatic, And educational purposes. The ISS provides a platform to conduct scientific research, With power, Data, Cooling, And crew available to support experiments. Small, Uncrewed spacecraft can also provide platforms for experiments, Especially those involving zero gravity and exposure to space. But space stations offer a long-term environment where studies can be performed potentially for decades, With ready access by human researchers. The ISS simplifies individual experiments by allowing groups of experiments to share the same launches and crew time. Research is conducted in a wide variety of fields, Including astrobiology, Astronomy, Physical sciences, Materials science, Space weather, Meteorology, And human research, Including space medicine and the life sciences. Scientists on Earth have timely access to the data and can suggest experimental modifications to the crew. If follow-on experiments are necessary, The routinely scheduled launches of resupply craft allows new hardware to be launched with relative ease. Crews fly expeditions of several months' duration, Providing approximately 160 man-hours per week of labor, With a crew of six. However, A considerable amount of crew time is taken up by station maintenance. A notable ISS experiment is the Alpha Magnetic Spectrometer, Which is intended to detect dark matter and answer other fundamental questions about the universe. According to NASA, The AMS is as important as the Hubble Space Telescope. It is docked on the station and could not have been easily accommodated on a free-flying satellite platform because of its power and bandwidth needs. On April 3rd, 2013, Scientists reported that hints of dark matter may have been detected by the AMS. According to these scientists, The first results from the space-borne Alpha Magnetic Spectrometer confirm an unexplained excess of high-energy positrons in Earth-bound cosmic rays. The space environment is hostile to life. Unprotected presence in space results in exposure to intense radiation, Consisting primarily of protons and other subatomic charged particles from the solar wind, In addition to cosmic rays, Vacuum, Extreme temperatures, And microgravity. Some simple forms of life called extremophiles, As well as small invertebrates called tardigrades, Can survive in this environment in an extremely dry state through desiccation. Medical research improves knowledge about the effects of long-term space exposure on the human body, Including muscle atrophy, Bone loss, And fluid shifts. This data will be used to determine whether long-lasting human spaceflight and space colonization is feasible. In 2006, Data on bone loss and muscular atrophy suggested that there would be a significant risk of fractures and movement problems if astronauts landed on a planet after a lengthy interplanetary cruise, Such as a six-month interval required to travel to Mars. Medical studies are conducted aboard the ISS on behalf of the National Space Biomedical Research Institute, NSBRI. Prominent among these is the Advanced Diagnostic Ultrasound and Microgravity Study, In which astronauts perform ultrasound scans under the guidance of remote experts. The study considers the diagnosis and treatment of medical conditions in space. There is usually no physician on board the ISS, And diagnosis of medical conditions is a challenge. It is anticipated that remotely guided ultrasound scans will have application on Earth in emergency and rural care situations, Where in-person access to a trained physician is difficult. In August 2020, Scientists reported that bacteria from Earth, Particularly Deinonychus radiodurans bacteria, Which is highly resistant to environmental hazards, Were found to survive for three years in outer space, Based on studies conducted on the International Space Station. These findings supported the notion of pansperma, The hypothesis that life exists throughout the universe, Distributed in various ways, Including space dust, Meteoroids, Asteroids, Comets, Planetoids, Or contaminated spacecraft. Remote sensing of the Earth, Astronomy and deep space research on the ISS have significantly increased during the 2010s after the completion of the U. S. Orbital segment in 2011. Throughout the more than 20 years of the ISS program, Researchers aboard the ISS and on the ground have examined aerosols, Ozone, Lightning, And oxides in Earth's atmosphere, As well as the Sun, Cosmic rays, Cosmic dust, Antimatter, And dark matter in the universe. Examples of Earth-viewing remote-sensing experiments that have flown on the ISS are the Orbiting Carbon Observatory-3, ISS RapidScat EcoStress, The Global Ecosystem Dynamics Investigation, And the Cloud Aerosol Transport System. ISS-based astronomy telescopes and experiments include SOLAR, The Neutron Star Interior Composition Explorer, The Calorimetric Electron Telescope, The monitor of all-sky X-ray image, And the alpha magnetic spectrometer. Researchers are investigating the effect of the station's near-weightless environment on the evolution, Development, Growth, And international processes of plants and animals. In response to some of the data, NASA wants to investigate microgravity's effects on the growth of three-dimensional human-like tissues and the unusual protein crystals that can be formed in space. Investigating the physics of fluids and microgravity will provide better models of the behavior of fluids. Because fluids can be almost completely combined in microgravity, Physicists investigate fluids that do not mix well on Earth. Examining reactions that are slowed by low gravity and low temperatures will improve our understanding of superconductivity. The study of materials science is an important ISS research activity with the objective of reaping economic benefits through the improvement of techniques used on Earth. Other areas of interest include the effect of low gravity on combustion through the study of the efficiency of burning and control of emissions and pollutants. These findings may improve knowledge about energy production and lead to economic and environmental benefits. The International Space Station is a product of global collaboration, With its components manufactured across the world. The modules of the Russian orbital segment, Including Zarya and Zvezda, Were produced at the Khrunichev State Research and Production Space Center in Moscow. Zvezda was initially manufactured in 1985 as a component for the Mir-2 space station, Which was never launched. Much of the U. S. Orbital segment, Including the Destiny and Unity modules, The integrated truss structure and solar arrays, Were built at NASA's Marshall Space Flight Center in Huntsville, Alabama, And Michoud Assembly Facility in New Orleans. These components underwent final assembly and processing for launch at the Operations and Checkout Building and the Space Station Processing Facility at the Kennedy Space Center in Florida. The U. S. Orbital segment also hosts the Columbus module contributed by the European Space Agency and built in Germany, The Kibo module contributed by Japan and built at the Tsukuba Space Center and the Institute of Space and Astronomical Science, Along with the Canadarm2 and Daxter, A joint Canadian-U. S. Endeavor. All of these components were shipped to the SSPF for launch processing. The assembly of the International Space Station, A major endeavor in space architecture, Began in November 1998. Modules in the Russian segment launched and docked autonomously, With the exception of Rassvet. Other modules and components were delivered by the Space Shuttle, Which then had to be installed by astronauts either remotely using robotic arms or doing spacewalks, More formally known as extravehicular activities, EVAs. By June 5, 2011, Astronauts had made over 159 EVAs to add components to the station, Totaling more than 1, 000 hours in space. The beginning of the core of the ISS's tenure in orbit was the launch of the Russian Beltsarya module atop a Proton rocket on November 20, 1998. Zarya provided propulsion, Communications, And electrical power. Two weeks later, On December 4, 1998, The American-made Unity was ferried aboard Space Shuttle Endeavour on STS-88 and joined with Zarya. Unity provided the connection between the Russian and US segments of the station, And would provide ports to connect future modules and visiting spacecraft. The atmosphere on board the ISS is similar to that of Earth. Normal air pressure on the ISS is 101. 3 kilopascals, The same as at sea level on Earth. While the crew would remain healthy at a lower pressure, Some equipment is very pressure sensitive. Double-sided solar arrays provide electrical power to the ISS. These bifacial cells collect direct sunlight on one side and light reflected off from the Earth on the other, And are more efficient and operate at a lower temperature than single-celled cells commonly used on Earth. The station originally used rechargeable nickel-hydrogen batteries for continuous power during the 45 minutes of every 90-minute orbit that is eclipsed by the Earth. The batteries are recharged on the day side of the orbit. They had a 6. 5 year lifetime and were regularly replaced over the anticipated 20 year life of the station. Starting in 2016, The nickel-hydrogen batteries were replaced by lithium-ion batteries, Which are expected to last until the end of the ISS program. The ISS relies on various radio communication systems to provide telemetry and scientific data links between the station and mission control centers. Radio links are also used during rendezvous and docking procedures, And for audio and video communication between crew members, Flight controllers, And family members. As a result, The ISS is equipped with internal and external communication systems used for different purposes. The US orbital segment of the ISS is equipped with approximately 100 commercial off-the-shelf laptops running Windows or Linux. These devices are modified to use the station's 28 volt DC power system, And with additional ventilation, Since heat generated by the devices can stagnate in the weightless environment. NASA prefers to keep a high commonality between laptops, And spare parts are kept on the station so astronauts can repair laptops when needed. As of June 2023, 13 individuals have paid for their own travel to visit the ISS. In news coverage, Such travelers are often referred to as space tourists. However, Many have objected to the term as they typically undergo professional training and conduct scientific, Educational, Or outreach activities while on orbit. Gravity at the altitude of the ISS is approximately 90% as strong as on Earth's surface, But objects in orbit are in continuous freefall, Resulting in a state of weightlessness known as microgravity. This perceived weightlessness is disturbed by five effects. On-board attitude control moment gyroscopes, Thrust firings for attitude or orbital changes. The living and working space aboard the International Space Station is larger than a six-bedroom house, Equipped with seven private sleeping quarters, Three bathrooms, Two dining rooms, A gym, And a panoramic 360-degree view bay window. The station provides dedicated crew quarters for long-term crew members. These soundproof person-sized booths offer privacy, Ventilation, And basic amenities such as a sleeping bag, A reading lamp, And storage for personal items. Visiting crew members use tethered sleeping bags attached to available wall space or inside their spacecraft. While it is possible to sleep floating freely, This is generally avoided to prevent collisions with sensitive equipment. The station's lighting system is adjustable, Allowing for dimming, Switching off, And color temperature changes to support crew activities and rest. The ISS operates on Coordinated Universal Time, UTC. A typical day aboard the ISS begins at 0600 with wake-up, Post-sleep routines, And a morning inspection of the station. After breakfast, The crew holds a daily planning conference with Mission Control, Starting work around 0810. Morning tasks include scheduled exercise, Scientific experiments, Maintenance, Or operational duties. Following a one-hour lunch break at 13. 05, The crew resumes their afternoon schedule of work and exercise. Pre-sleep activities including dinner and a crew conference begin at 19. 30, With a scheduled sleep period starting at 21. 30. The crew works approximately 10 hours on weekdays and 5 hours on Saturdays, With the remaining time allocated for relaxation or catching up on tasks. Free time often involves enjoying personal hobbies, Communicating with family, Or gazing out at Earth through the station's windows. The crew can watch TV aboard the station. To simulate night conditions, The station's windows are covered during designated sleep periods, As the ISS experiences 16 sunrises and sunsets daily due to its orbital speed. Reflection of individual and crew characteristics are found particularly in the decoration of the station, And expressions in general, Such as religion. Food aboard the International Space Station is preserved and packaged to withstand long storage times, Minimize waste, And prevent contamination of station systems. Because microgravity dulls taste, Meals are often seasoned more heavily than on Earth. Crews particularly look forward to resupply missions, Which deliver perishable items such as fresh fruit and vegetables. To reduce the risk of crumbs and spills damaging equipment. Foods are prepared in specialized packaging. Liquid condiments are preferred over powdered ones. And containers are secured with Velcro or magnets. Drinks are delivered as powders to be mixed with water, While soups and beverages are sipped from plastic bags with straws. Solid foods are eaten with utensils attached to trays by magnets, And any stray food must be collected to prevent it from clogging air filters and other systems. While crews occasionally gather for group meals in unity, Especially during holidays or special occasions, They more often eat in small groups because of differing schedules. Russian cosmonauts also retain the option of dining separately in Sviazda, Where the can warmer is located. With the growing diversity of NASA's astronaut corps and the large number of international astronauts who have flown to the ISS, The variety of food available has expanded significantly. Efforts are made to provide meals that reflect astronauts' cultural backgrounds and personal preferences. And food is often shared among crew members. Experiments have also been conducted aboard the ISS to grow fresh vegetables in orbit. These studies aim to supplement astronauts' diets with additional nutrients, Provide psychological benefits, And advance space agricultural techniques needed for long-duration missions to the Moon and Mars. As of 2023, Crops grown include three types of lettuce, Chinese cabbage, Mizuna mustard, And red Russian kale. Some of the plants are harvested and eaten by the crew, While others were returned to Earth for analysis. In the future, NASA plans to grow tomatoes and peppers, And eventually berries, Beans, And other nutrient-rich foods. Such crops could offer not only improved nutrition, But also potential protection against space radiation for crew members who consume them. The ISS is equipped with three Russian-designed toilets, Located in Zvezda, Tranquility and Nauka. Inside these waste and hygiene compartments, The occupant fastens themselves to the toilet seat, Which is equipped with spring-loaded restraining bars to ensure a proper seal. A lever activates a powerful fan while opening a suction port at the bottom of the toilet bowl, And the airstream carries waste away. Solid waste is stored in individual bags placed in an aluminum container, Which is later transferred to cargo spacecraft that will burn up on re-entry. Liquid waste is collected through a hose with anatomically shaped funnel adapters so that both men and women can use the same system. The urine is diverted to the water recovery system where it is processed into drinking water. Showers were first introduced on space stations in the early 1970s aboard Skylab and Salyut 3. However, Crews complained about the complexity of showering, And by the time of Solute 6 in the early 1980s, It had been reduced to a monthly activity. The ISS, Like later Russian stations after, Has no shower. Instead, Astronauts clean themselves with wet wipes or with a water jet, And using soap dispense from a toothpaste-like tube. Rinceless shampoo and edible toothpaste are also provided to conserve water.