Editing International Space Station (section)

==Life aboard==
===Living quarters===
[[File:Nikolai Budarin in a sleep station in Zvezda.jpg|thumb|Cosmonaut [[Nikolai Budarin]] at work inside the ''[[Zvezda (ISS module)|Zvezda]]'' service module crew quarters]]The living and working space aboard the International Space Station (ISS) 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.<ref>{{Cite web |last=Howell |first=Elizabeth |date=24 August 2022 |title=International Space Station: Facts, History & Tracking |url=https://www.space.com/16748-international-space-station.html |url-status=live |archive-url=https://web.archive.org/web/20190401024329/https://www.space.com/16748-international-space-station.html |archive-date=1 April 2019 |access-date=27 April 2024 |website=Space.com}}</ref>

The station provides dedicated crew quarters for long-term crew members. Two "sleep stations" are located in the ''Zvezda'' module, one in ''Nauka'', and four in ''Harmony''.<ref name="roscomos-20210811">{{Cite web |date=11 August 2021 |title=Новости. Космонавт рассказал, кто может первым заселиться в модуль "Наука" на МКС |trans-title=A cosmonaut explained who can be the first to settle in the 'Nauka' module on the ISS |url=https://www.roscosmos.ru/32150/ |url-status=dead |archive-url=https://web.archive.org/web/20220822052138/https://www.roscosmos.ru/32150/ |archive-date=22 August 2022 |access-date=12 August 2021 |publisher=[[Roscosmos]] |language=ru}}</ref><ref>{{cite web |date=6 December 2010 |title=At Home with Commander Scott Kelly (Video) |url=https://www.youtube.com/watch?v=Q4dG9vSyUFQ |url-status=live |archive-url=https://ghostarchive.org/varchive/youtube/20211211/Q4dG9vSyUFQ |archive-date=11 December 2021 |access-date=8 May 2011 |publisher=NASA |location=International Space Station}}{{cbignore}}</ref><ref name="roscomos-nauka-booklet">{{Cite web |title=Nauka module prelaunch booklet |url=https://www.roscosmos.ru/media/files/nauka.pdf |url-status=dead |archive-url=https://web.archive.org/web/20220822181356/https://www.roscosmos.ru/media/files/nauka.pdf |archive-date=22 August 2022 |publisher=[[Roscosmos]]}}</ref><ref name="sae-08ICES-0222">{{Cite conference |last1=Broyan |first1=James Lee |last2=Borrego |first2=Melissa Ann |last3=Bahr |first3=Juergen F. |year=2008 |title=International Space Station USOS Crew Quarters Development |url=https://ntrs.nasa.gov/api/citations/20080013462/downloads/20080013462.pdf |conference=International Conference on Environmental Systems |location=San Francisco, California |publisher=[[SAE International]] |volume=38 |id=08ICES-0222 |archive-url=https://web.archive.org/web/20231118224703/https://ntrs.nasa.gov/api/citations/20080013462/downloads/20080013462.pdf |archive-date=18 November 2023 |access-date=8 May 2011 |url-status=live}}</ref> These soundproof, person-sized booths offer privacy, ventilation, and basic amenities such as a sleeping bag, a reading lamp, a desktop, a shelf, and storage for personal items.<ref name="ESALife">{{Cite web |date=19 July 2004 |title=Daily life |url=https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Astronauts/Daily_life |url-status=live |archive-url=https://web.archive.org/web/20230812210927/https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Astronauts/Daily_life |archive-date=12 August 2023 |access-date=28 October 2009 |publisher=[[European Space Agency]]}}</ref><ref name="NASACrewEquip">{{cite web |last=Mansfield |first=Cheryl L. |date=7 November 2008 |title=Station Prepares for Expanding Crew |url=http://www.nasa.gov/mission_pages/station/behindscenes/126_payload.html |url-status=dead |archive-url=https://web.archive.org/web/20081204054653/http://www.nasa.gov/mission_pages/station/behindscenes/126_payload.html |archive-date=4 December 2008 |access-date=17 September 2009 |publisher=NASA}}</ref><ref name="CSALife">{{cite web |title=Living and Working on the International Space Station |url=http://www.asc-csa.gc.ca/pdf/educator-liv_wor_iss.pdf |url-status=dead |archive-url=https://web.archive.org/web/20090419045323/http://www.asc-csa.gc.ca/pdf/educator-liv_wor_iss.pdf |archive-date=19 April 2009 |access-date=28 October 2009 |publisher=CSA}}</ref> The quarters in ''Zvezda'' include a small window but have less ventilation and soundproofing.

Visiting crew members use tethered sleeping bags attached to available wall space. While it is possible to sleep floating freely, this is generally avoided to prevent collisions with sensitive equipment.<ref name="SRLife">{{Cite news |last=Malik |first=Tariq |date=27 July 2009 |title=Sleeping in Space is Easy, But There's No Shower |url=https://www.space.com/7060-sleeping-space-easy-shower.html |url-status=live |archive-url=https://web.archive.org/web/20230812222844/https://www.space.com/7060-sleeping-space-easy-shower.html |archive-date=12 August 2023 |access-date=29 October 2009 |work=[[Space.com]]}}</ref> Proper ventilation is critical, as astronauts risk oxygen deprivation if exhaled carbon dioxide accumulates in a bubble around their heads.<ref name="ESALife" />

The station’s lighting system is adjustable, allowing for dimming, switching off, and [[color temperature|colour temperature]] changes to support crew activities and rest.<ref>{{Cite AV media |url=https://www.youtube.com/watch?v=yNgMzNN23kE |title=Bedtime in space |time={{time needed|date=September 2019}} |access-date=21 September 2019 |archive-url=https://ghostarchive.org/varchive/youtube/20211211/yNgMzNN23kE |archive-date=11 December 2021 |url-status=live |via=YouTube}}{{cbignore}}</ref><ref name="nasa-stem-sleepscience">{{Cite web |date=13 December 2018 |title=STEMonstrations: Sleep Science |url=https://images.nasa.gov/details-jsc2018m000902-STEMonstrations_Sleep_Science_MP4 |url-status=live |archive-url=https://web.archive.org/web/20231125172450/https://images.nasa.gov/details-jsc2018m000902-STEMonstrations_Sleep_Science_MP4 |archive-date=25 November 2023 |access-date=13 June 2020 |website=NASA Image and Video Library |publisher=[[NASA]] |format=AV media |id=jsc2018m000902-STEMonstrations_Sleep_Science_MP4}}</ref>

===Crew activities===
[[File:Exp18home nasa big.jpg|thumb|Engineer [[Gregory Chamitoff]] looking out of a window|left]]

The ISS operates on [[Coordinated Universal Time]] (UTC).<ref name="bbc-iss-timezone">{{Cite magazine |last=Mitchell |first=Gareth |title=What time zone do they use on the International Space Station? |url=https://www.sciencefocus.com/space/what-time-zone-do-they-use-on-the-international-space-station/ |url-status=live |archive-url=https://web.archive.org/web/20230324101052/https://www.sciencefocus.com/space/what-time-zone-do-they-use-on-the-international-space-station/ |archive-date=24 March 2023 |access-date=26 May 2021 |magazine=[[BBC Science Focus]]}}</ref> A typical day aboard the ISS begins at 06:00 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 08:10. 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 the scheduled sleep period starting at 21:30.<ref name=":3">{{cite web |date=5 November 2008 |title=ISS Crew Timeline |url=http://www.nasa.gov/pdf/287386main_110508_tl.pdf |url-status=dead |archive-url=https://web.archive.org/web/20160730044854/http://www.nasa.gov/pdf/287386main_110508_tl.pdf |archive-date=30 July 2016 |access-date=5 November 2008 |publisher=NASA}}</ref>

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.<ref name=":3" /> The crew can watch TV aboard the station.<ref>{{Cite news |last=Novak |first=Matt |date=4 August 2024 |title=Every TV Show Astronauts Can Watch on the ISS Right Now |url=https://gizmodo.com/every-tv-show-astronauts-can-watch-on-the-iss-right-now-1851567279 |access-date=13 February 2025 |work=Gizmodo |type=Digital}}</ref>

When the Space Shuttle was operating, the ISS crew aligned with the shuttle crew's [[Mission Elapsed Time]], a flexible schedule based on the shuttle's launch.<ref>{{cite web |title=NASA – Time in Space, A Space in Time |url=https://www.nasa.gov/mission_pages/station/research/news/time_in_space.html |url-status=dead |archive-url=https://web.archive.org/web/20150420050836/http://www.nasa.gov/mission_pages/station/research/news/time_in_space.html |archive-date=20 April 2015 |access-date=5 May 2015 |website=nasa.gov}}</ref><ref>{{cite web |date=17 March 2013 |title=A Slice of Time Pie |url=http://blogs.nasa.gov/cm/blog/ISS%20Science%20Blog/posts/post_1340820317951.html |url-status=dead |archive-url=https://web.archive.org/web/20130317075600/http://blogs.nasa.gov/cm/blog/ISS%20Science%20Blog/posts/post_1340820317951.html |archive-date=17 March 2013 |access-date=5 May 2015}}</ref><ref>{{cite web |title=Human Space Flight (HSF) – Crew Answers |url=http://spaceflight.nasa.gov/feedback/expert/answer/crew/sts-113/index_2.html |url-status=dead |archive-url=https://web.archive.org/web/20110721054011/http://spaceflight.nasa.gov/feedback/expert/answer/crew/sts-113/index_2.html |archive-date=21 July 2011 |access-date=5 May 2015 |website=spaceflight.nasa.gov}}</ref>

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 and material culture ===
Reflection of individual and crew characteristics are found particularly in the decoration of the station and expressions in general, such as religion.<ref name="z534">{{cite web|last=Archaeology|first=ISS|title=Religious life on ISS|website=ISS Archaeology|date=11 November 2017|url=https://issarchaeology.org/religious-life-on-iss/|access-date=22 July 2024}}</ref> The latter has produced a certain material economy between the station and Russia in particular.<ref name="q938">{{cite journal|last1=Salmond|first1=Wendy|last2=Walsh|first2=Justin|last3=Gorman|first3=Alice|title=Eternity in Low Earth Orbit: Icons on the International Space Station|journal=Religions|volume=11|issue=11|date=17 November 2020|issn=2077-1444|doi=10.3390/rel11110611|doi-access=free|page=611}}</ref>

The micro-society of the station, as well as wider society, and possibly the emergence of distinct station cultures,<ref name="p157">{{cite journal|last1=Walsh|first1=Justin St. P.|last2=Gorman|first2=Alice C.|last3=Salmond|first3=Wendy|title=Visual Displays in Space Station Culture: An Archaeological Analysis|journal=Current Anthropology|volume=62|issue=6|date=1 December 2021|issn=0011-3204|doi=10.1086/717778|pages=804–818|doi-access=free}}</ref> is being studied by analyzing many aspects, from art to dust accumulation, as well as archaeologically how material of the ISS has been discarded.<ref name="e121">{{cite web|title=Life and culture on the International Space Station|website=News|date=10 October 2021|url=https://news.flinders.edu.au/blog/2021/10/11/life-and-culture-on-the-international-space-station/|access-date=22 July 2024}}</ref>

===Food and personal hygiene===
{{See also|Space food}}
{{multiple image
| align             = left
| total_width       = 350
| image1            = Zvezda toilet.jpg
| caption1          = The space toilet in the ''[[Zvezda (ISS module)|Zvezda]]'' module in the Russian segment
| image2            = Node_3_toilet.jpg
| caption2          = The main toilet in the US Segment inside the ''[[Tranquility (ISS module)|Tranquility]]'' module
| caption3          = 
| footer            = * Both toilets are a Russian design.
}}
[[File:Meal STS127.jpg|thumb|alt=Nine astronauts seated around a table covered in open cans of food strapped down to the table. In the background a selection of equipment is visible, as well as the salmon-coloured walls of the ''Unity'' node.|The crews of [[Expedition 20]] and [[STS-127]] enjoy a meal inside ''Unity''.]]
[[File:ISS-43 Food table in the Unity module.jpg|thumb|Main dining desk in Node 1]]
[[File:ScienceCasts- Historic Vegetable Moment on the Space Station.webm|thumb|Fresh fruits and vegetables are grown in the ISS.]]
On the USOS, most of the food aboard is vacuum sealed in plastic bags; cans are rare because they are heavy and expensive to transport. Preserved food is not highly regarded by the crew and taste is reduced in microgravity,<ref name="ESALife" /> so efforts are taken to make the food more palatable, including using more spices than in regular cooking. The crew looks forward to the arrival of any spacecraft from Earth as they bring fresh fruit and vegetables. Care is taken that foods do not create crumbs, and liquid condiments are preferred over solid to avoid contaminating station equipment. Each crew member has individual food packages and cooks them in the [[Galley (kitchen)|galley]], which has two food warmers, a refrigerator (added in November 2008), and a water dispenser that provides heated and unheated water.<ref name="NASACrewEquip" /> Drinks are provided as dehydrated powder that is mixed with water before consumption.<ref name="NASACrewEquip" /><ref name="CSALife" /> Drinks and soups are sipped from plastic bags with straws, while solid food is eaten with a knife and fork attached to a tray with magnets to prevent them from floating away. Any food that floats away, including crumbs, must be collected to prevent it from clogging the station's air filters and other equipment.<ref name="CSALife" />

Showers on space stations were introduced in the early 1970s on ''Skylab'' and ''Salyut''&nbsp;3.<ref name="livingandworking">{{Cite web|url=https://history.nasa.gov/SP-4208/contents.htm|title=Living and Working in Space: A History of Skylab|last1=Benson|first1=Charles Dunlap|last2=Compton|first2=William David|date=January 1983|publisher=[[NASA]]|id=SP-4208|url-status=live|archive-url=https://web.archive.org/web/20231124155632/https://history.nasa.gov/SP-4208/contents.htm|archive-date=24 November 2023}}</ref>{{rp|139}}<!--<ref name="belew1977" />{{rp|80}}--> By ''Salyut'' 6, in the early 1980s, the crew complained of the complexity of showering in space, which was a monthly activity.<ref name="Portree1995-86">{{Cite tech report|url=https://history.nasa.gov/SP-4225/documentation/mhh/mirheritage.pdf|title=Mir Hardware Heritage|last=Portree|first=David S. F.|date=March 1995|publisher=[[NASA]]|page=86|oclc=755272548|id=Reference Publication 1357|url-status=live|archive-url=https://web.archive.org/web/20230810130808/https://history.nasa.gov/SP-4225/documentation/mhh/mirheritage.pdf|archive-date=10 August 2023}}</ref> The ISS does not feature a shower; instead, crewmembers wash using a water jet and wet wipes, with soap dispensed from a toothpaste tube-like container. Crews are also provided with rinseless shampoo and edible toothpaste to save water.<ref name="SRLife" /><ref>{{Cite AV media|url=https://www.youtube.com/watch?v=uIjNfZbUYu8|archive-url=https://ghostarchive.org/varchive/youtube/20211211/uIjNfZbUYu8|archive-date=11 December 2021|url-status=live|title=Karen Nyberg Shows How You Wash Hair in Space|date=12 July 2013|last=Nyberg|first=Karen|publisher=NASA|access-date=6 June 2015|via=YouTube}}{{cbignore}}</ref>

There are two [[space toilet]]s on the ISS, both of Russian design, located in ''Zvezda'' and ''Tranquility''.<ref name="NASACrewEquip" /> These Waste and Hygiene Compartments use a fan-driven suction system similar to the Space Shuttle Waste Collection System. Astronauts first fasten themselves to the toilet seat, which is equipped with spring-loaded restraining bars to ensure a good seal.<ref name="ESALife" /> A lever operates a powerful fan and a suction hole slides open: the air stream carries the waste away. Solid waste is collected in individual bags which are stored in an aluminium container. Full containers are transferred to Progress spacecraft for disposal.<ref name="NASACrewEquip" /><ref>{{cite web|last=Lu|first=Ed|date=8 September 2003|title=Greetings Earthling|url=http://spaceflight.nasa.gov/station/crew/exp7/luletters/lu_letter9.html|access-date=1 November 2009|publisher=NASA|archive-date=1 September 2012|archive-url=https://web.archive.org/web/20120901183936/http://spaceflight.nasa.gov/station/crew/exp7/luletters/lu_letter9.html|url-status=dead}}</ref> Liquid waste is evacuated by a hose connected to the front of the toilet, with anatomically correct "urine funnel adapters" attached to the tube so that men and women can use the same toilet. [[Urine diversion|The diverted urine]] is collected and transferred to the Water Recovery System, where it is recycled into drinking water.<ref name="CSALife" /> In 2021, the arrival of the Nauka module also brought a third toilet to the ISS.<ref>{{Cite AV media|url=https://www.youtube.com/watch?v=fJyMw5J-GsQ|archive-url=https://ghostarchive.org/varchive/youtube/20211211/fJyMw5J-GsQ|archive-date=11 December 2021|url-status=live|title=Thomas tours the MLM module (in French with English subtitles available)|date=18 August 2021|last=Pesquet|first=Thomas|publisher=ESA|access-date=29 August 2021|via=YouTube}}{{cbignore}}</ref>

===Crew health and safety===
{{Main|Effect of spaceflight on the human body}}

====Overall====
On 12 April 2019, NASA reported medical results from the [[ISS year long mission|Astronaut Twin Study]]. Astronaut [[Scott Kelly (astronaut)|Scott Kelly]] spent a year in space on the ISS, while [[Mark Kelly|his identical twin]] spent the year on Earth. Several long-lasting changes were observed, including those related to alterations in [[DNA]] and [[cognition]], when one twin was compared with the other.<ref name="NYT-20190412">{{Cite news|url=https://www.nytimes.com/2019/04/11/science/scott-mark-kelly-twins-space-nasa.html|url-access=subscription|title=Scott Kelly Spent a Year in Orbit. His Body Is Not Quite the Same|last=Zimmer|first=Carl|author-link=Carl Zimmer|date=11 April 2019|access-date=12 April 2019|url-status=live|archive-url=https://web.archive.org/web/20200522170617/https://www.nytimes.com/2019/04/11/science/scott-mark-kelly-twins-space-nasa.html|archive-date=22 May 2020|quote=NASA scientists compared the astronaut to his earthbound twin, Mark. The results hint at what humans will have to endure on long journeys through space.|work=The New York Times}}</ref><ref name="SCI-20190412">{{Cite journal|title=The NASA Twins Study: A multidimensional analysis of a year-long human spaceflight|last=Garrett-Bakeman|first=Francine E.|date=12 April 2019|pages=eaau8650|bibcode=2019Sci...364.8650G|doi=10.1126/science.aau8650|display-authors=et al.|volume=364|journal=[[Science (journal)|Science]]|pmc=7580864|issue=6436|pmid=30975860}}</ref>

In November 2019, researchers reported that astronauts experienced serious [[Hemodynamics|blood flow]] and [[Thrombus|clot]] problems while on board the ISS, based on a six-month study of 11 healthy astronauts. The results may influence long-term spaceflight, including a mission to the planet Mars, according to the researchers.<ref name="CNN-20191115">{{Cite news|url=https://www.cnn.com/2019/11/15/health/astronaut-blood-flow-clot-scn-trnd/index.html|title=Astronauts experienced reverse blood flow and blood clots on the space station, study says|last=Strickland|first=Ashley|date=15 November 2019|access-date=16 November 2019|url-status=live|archive-url=https://web.archive.org/web/20230811175409/https://edition.cnn.com/2019/11/15/health/astronaut-blood-flow-clot-scn-trnd/index.html|archive-date=11 August 2023|publisher=CNN}}</ref><ref name="JAMA-20191113">{{Cite journal|last=Marshall-Goebel|first=Karina|display-authors=et al.|date=13 November 2019|title=Assessment of Jugular Venous Blood Flow Stasis and Thrombosis During Spaceflight|journal=[[JAMA Network Open]]|volume=2|issue=11|pages=e1915011|doi=10.1001/jamanetworkopen.2019.15011|pmc=6902784|pmid=31722025}}</ref>

====Radiation====
{{See also|Coronal mass ejection}}
[[File:Aurora Australis from ISS 2011 - 1.ogv|thumb|upright=1.1|Video of the [[Aurora Australis]], taken by the crew of [[Expedition 28]] on an ascending pass from south of [[Madagascar]] to just north of Australia over the Indian Ocean]]

The ISS is partially protected from the space environment by [[Earth's magnetic field]]. From an average distance of about {{convert|70000|km|abbr=on}} from the Earth's surface, depending on Solar activity, the [[magnetosphere]] begins to deflect [[solar wind]] around Earth and the space station. [[Solar flare]]s are still a hazard to the crew, who may receive only a few minutes warning. In 2005, during the initial "proton storm" of an X-3 class solar flare, the crew of [[Expedition 10]] took shelter in a more heavily shielded part of the ROS designed for this purpose.<ref name="spacecom-20060223">{{Cite news|url=https://www.space.com/2080-solar-flare-hits-earth-mars.html|title=Solar Flare Hits Earth and Mars|last=Than|first=Ker|date=23 February 2006|url-status=live|archive-url=https://web.archive.org/web/20230811164550/https://www.space.com/2080-solar-flare-hits-earth-mars.html|archive-date=11 August 2023|work=[[Space.com]]}}</ref><ref>{{cite web|date=10 June 2005|title=A new kind of solar storm|url=https://science.nasa.gov/science-news/science-at-nasa/2005/10jun_newstorm/|publisher=NASA|access-date=12 July 2017|archive-date=16 May 2017|archive-url=https://web.archive.org/web/20170516030602/https://science.nasa.gov/science-news/science-at-nasa/2005/10jun_newstorm/|url-status=dead}}</ref>

Subatomic charged particles, primarily [[proton]]s from cosmic rays and solar wind, are normally absorbed by Earth's atmosphere. When they interact in sufficient quantity, their effect is visible to the naked eye in a phenomenon called an [[aurora]]. Outside Earth's atmosphere, ISS crews are exposed to approximately one [[millisievert]] each day (about a year's worth of natural exposure on Earth), resulting in a higher risk of cancer. Radiation can penetrate living tissue and damage the DNA and [[chromosome]]s of [[lymphocyte]]s; being central to the [[immune system]], any damage to these cells could contribute to the lower [[immunity (medical)|immunity]] experienced by astronauts. Radiation has also been linked to a higher incidence of [[cataract]]s in astronauts. Protective shielding and medications may lower the risks to an acceptable level.<ref name="JCB" />

Radiation levels on the ISS are between 12 and 28.8 milli rads per day,<ref name="Forbes 2018">{{Cite web|url=https://www.forbes.com/sites/quora/2018/11/13/how-much-radiation-are-iss-astronauts-exposed-to/|title=How Much Radiation Are ISS Astronauts Exposed To?|last=Frost|first=Robert|date=13 November 2018|work=[[Forbes]]|access-date=4 September 2022|url-status=live|archive-url=https://web.archive.org/web/20230810131701/https://www.forbes.com/sites/quora/2018/11/13/how-much-radiation-are-iss-astronauts-exposed-to/?sh=704809db18a9|archive-date=10 August 2023}}</ref> about five times greater than those experienced by airline passengers and crew, as Earth's electromagnetic field provides almost the same level of protection against solar and other types of radiation in low Earth orbit as in the stratosphere. For example, on a 12-hour flight, an airline passenger would experience 0.1 millisieverts of radiation, or a rate of 0.2 millisieverts per day; this is one fifth the rate experienced by an astronaut in LEO. Additionally, airline passengers experience this level of radiation for a few hours of flight, while the ISS crew are exposed for their whole stay on board the station.<ref>{{cite web|title=Galactic Radiation Received in Flight|url=http://jag.cami.jccbi.gov./cariprofile.asp|url-status=dead|archive-url=https://web.archive.org/web/20100329130826/http://jag.cami.jccbi.gov/cariprofile.asp|archive-date=29 March 2010|access-date=20 May 2010|publisher=FAA Civil Aeromedical Institute}}</ref>

====Stress====
There is considerable evidence that [[psychosocial]] stressors are among the most important impediments to optimal crew morale and performance.<ref>{{cite book|last1=Suedfeld|first1=Peter|author1-link=Peter Suedfeld|last2=Wilk|first2=Kasia E.|last3=Cassel|first3=Lindi|contribution=Flying with Strangers: Postmission Reflections of Multinational Space Crews|title=Psychology of Space Exploration, Contemporary Research in Historical Perspective|editor-last=Vakoch|editor-first=Douglas A.|year=2011|publisher=CreateSpace Independent Publishing Platform|pages=143–176|isbn=978-1-46999770-4}}</ref> Cosmonaut [[Valery Ryumin]] wrote in his journal during a particularly difficult period on board the [[Salyut 6|''Salyut'' 6]] space station: "All the conditions necessary for murder are met if you shut two men in a cabin measuring 18 feet by 20 [5.5&nbsp;m × 6&nbsp;m] and leave them together for two months."

NASA's interest in [[Stress (psychological)|psychological stress]] caused by space travel, initially studied when their crewed missions began, was rekindled when astronauts joined cosmonauts on the Russian space station ''Mir''. Common sources of stress in early US missions included maintaining high performance under public scrutiny and isolation from peers and family. The latter is still often a cause of stress on the ISS, such as when the mother of NASA astronaut [[Daniel M. Tani|Daniel Tani]] died in a car accident, and when Michael Fincke was forced to miss the birth of his second child.

A study of the longest spaceflight concluded that the first three weeks are a critical period where attention is adversely affected because of the demand to adjust to the extreme change of environment.<ref>{{Cite journal|last1=Manzey|first1=D.|last2=Lorenz|first2=B.|last3=Poljakov|first3=V.|year=1998|title=Mental performance in extreme environments: Results from a performance monitoring study during a 438-day spaceflight|journal=Ergonomics|volume=41|issue=4|pages=537–559|doi=10.1080/001401398186991|pmid=9557591}}</ref> ISS crew flights typically last about five to six months.

The ISS working environment includes further stress caused by living and working in cramped conditions with people from very different cultures who speak a different language. First-generation space stations had crews who spoke a single language; second- and third-generation stations have crew from many cultures who speak many languages. Astronauts must speak English and Russian, and knowing additional languages is even better.<ref>{{cite web|date=23 August 2004|title=Behind the Scenes: The Making of an Astronaut|url=https://spaceflight.nasa.gov/shuttle/support/training/isstraining/index.html|publisher=NASA|access-date=29 June 2018|archive-date=19 July 2016|archive-url=https://web.archive.org/web/20160719025001/http://spaceflight.nasa.gov/shuttle/support/training/isstraining/index.html|url-status=dead}}</ref>

Due to the lack of gravity, confusion often occurs. Even though there is no up and down in space, some crew members feel like they are oriented upside down. They may also have difficulty measuring distances. This can cause problems like getting lost inside the space station, pulling switches in the wrong direction or misjudging the speed of an approaching vehicle during docking.<ref name="bbc-20141007">{{Cite news|url=https://www.bbc.com/future/article/20141007-why-astronauts-get-space-stupid|title=Why astronauts get the 'space stupids'|last=Robson|first=David|date=7 October 2014|publisher=BBC|url-status=live|archive-url=https://web.archive.org/web/20230811164510/https://www.bbc.com/future/article/20141007-why-astronauts-get-space-stupid|archive-date=11 August 2023}}</ref>

====Medical====
[[File:Frank De Winne on treadmill cropped.jpg|thumb|Astronaut [[Frank De Winne]], attached to the [[Treadmill with Vibration Isolation Stabilization|TVIS treadmill]] with bungee cords aboard the ISS|alt=A man running on a treadmill, smiling at the camera, with bungee cords stretching down from his waistband to the sides of the treadmill]]
The [[physiology|physiological]] effects of long-term weightlessness include [[muscle atrophy]], deterioration of the skeleton ([[spaceflight osteopenia|osteopenia]]), fluid redistribution, a slowing of the cardiovascular system, decreased production of red blood cells, balance disorders, and a weakening of the immune system. Lesser symptoms include loss of body mass, and puffiness of the face.<ref name="JCB" />

Sleep is regularly disturbed on the ISS because of mission demands, such as incoming or departing spacecraft. Sound levels in the station are unavoidably high. The atmosphere is unable to [[thermosiphon]] naturally, so fans are required at all times to process the air which would stagnate in the freefall (zero-G) environment.

To prevent some of the adverse effects on the body, the station is equipped with: two [[Treadmill with Vibration Isolation Stabilization|TVIS]] treadmills (including the COLBERT); the [[ARED]] (Advanced Resistive Exercise Device), which enables various weightlifting exercises that add muscle without raising (or compensating for) the astronauts' reduced bone density;<ref>{{Cite journal|last1=Schneider|first1=S. M.|last2=Amonette|first2=W. E.|last3=Blazine|first3=K.|last4=Bentley|first4=J.|last5=c. Lee|first5=S. M.|last6=Loehr|first6=J. A.|last7=Moore|first7=A. D.|last8=Rapley|first8=M.|last9=Mulder|first9=E. R. |last10=Smith |first10=S. M.|year=2003|title=Training with the International Space Station Interim Resistive Exercise Device|journal=Medicine & Science in Sports & Exercise|volume=35|issue=11|pages=1935–1945|doi=10.1249/01.MSS.0000093611.88198.08|pmid=14600562|doi-access=free}}</ref> and a stationary bicycle. Each astronaut spends at least two hours per day exercising on the equipment.<ref name="ESALife" /><ref name="NASACrewEquip" /> Astronauts use bungee cords to strap themselves to the treadmill.<ref>{{cite web|date=16 June 2009|title=Bungee Cords Keep Astronauts Grounded While Running|url=http://www.nasa.gov/mission_pages/station/behindscenes/bungee_running.html|access-date=23 August 2009|publisher=NASA|archive-date=15 August 2009|archive-url=https://web.archive.org/web/20090815015910/http://www.nasa.gov/mission_pages/station/behindscenes/bungee_running.html|url-status=dead}}</ref><ref>{{cite web|last=Kauderer|first=Amiko|date=19 August 2009|title=Do Tread on Me|url=http://www.nasa.gov/mission_pages/station/behindscenes/colbert_feature.html|access-date=23 August 2009|publisher=NASA|archive-date=21 August 2009|archive-url=https://web.archive.org/web/20090821165909/http://www.nasa.gov/mission_pages/station/behindscenes/colbert_feature.html|url-status=dead}}</ref>

====Microbiological environmental hazards====
{{see also|Mir#Microbiological environmental hazards|l1=Microbiological environmental hazards on the Mir space station}}
Hazardous molds that can foul air and water filters may develop aboard space stations. They can produce acids that degrade metal, glass, and rubber. They can also be harmful to the crew's health. Microbiological hazards have led to a development of the [[LOCAD#Portable Test System|LOCAD-PTS]] (a portable test system) which identifies common bacteria and molds faster than standard methods of [[Cell culture|culturing]], which may require a sample to be sent back to Earth.<ref>{{cite web|last=Bell|first=Trudy E.|date=11 May 2007|title=Preventing "Sick" Spaceships|url=https://science.nasa.gov/science-news/science-at-nasa/2007/11may_locad3/|access-date=29 March 2015|publisher=NASA|archive-date=14 May 2017|archive-url=https://web.archive.org/web/20170514233537/https://science.nasa.gov/science-news/science-at-nasa/2007/11may_locad3|url-status=dead}}</ref> Researchers in 2018 reported, after detecting the presence of five ''[[Enterobacter|Enterobacter bugandensis]]'' bacterial strains on the ISS (none of which are [[pathogen]]ic to humans), that microorganisms on the ISS should be carefully monitored to continue assuring a medically healthy environment for astronauts.<ref name="EA-20181122">{{Cite press release|url=https://www.biomedcentral.com/about/press-centre/science-press-releases/23-11-18|title=ISS microbes should be monitored to avoid threat to astronaut health|last=Korn|first=Anne|date=23 November 2018|publisher=[[BioMed Central]]|access-date=11 January 2019|url-status=live|archive-url=https://web.archive.org/web/20230810145840/https://www.biomedcentral.com/about/press-centre/science-press-releases/23-11-18|archive-date=10 August 2023}}</ref><ref name="BMC-20181123">{{Cite journal|last1=Singh|first1=Nitin K.|last2=Bezdan|first2=Daniela|last3=Sielaff|first3=Aleksandra Checinska|last4=Wheeler|first4=Kevin|last5=Mason|first5=Christopher E.|last6=Vendateswaran|first6=Kasthuri|display-authors=1|date=23 November 2018|title=Multi-drug resistant Enterobacter bugandensis species isolated from the International Space Station and comparative genomic analyses with human pathogenic strains|journal=[[BMC Microbiology]]|volume=18|issue=1|page=175|doi=10.1186/s12866-018-1325-2|pmc=6251167|pmid=30466389|doi-access=free|bibcode=2018BMCMb..18..175S }}</ref>

Contamination on space stations can be prevented by reduced humidity, and by using paint that contains mold-killing chemicals, as well as the use of antiseptic solutions. All materials used in the ISS are tested for resistance against [[fungi]].<ref>{{cite web|first=Patrick L.|last=Barry|year=2000|title=Microscopic Stowaways on the ISS|url=https://science.nasa.gov/science-news/science-at-nasa/2000/ast26nov_1/|access-date=29 March 2015|archive-date=2 March 2015|archive-url=https://web.archive.org/web/20150302090949/http://science.nasa.gov/science-news/science-at-nasa/2000/ast26nov_1/|url-status=dead}}</ref> Since 2016, a series of ESA-sponsored experiments have been conducted to test the anti-bacterial properties of various materials, with the goal of developing "smart surfaces" that mitigate bacterial growth in multiple ways, using the best method for a particular circumstance. Dubbed "Microbial Aerosol Tethering on Innovative Surfaces" (MATISS), the programme involves deployment of small plaques containing an array of glass squares covered with different test coatings. They remain on the station for six months before being returned to earth for analysis.<ref name="eoportal-iss-matiss">{{Cite web|url=https://www.eoportal.org/other-space-activities/iss-matiss|title=ISS: MATISS|date=30 June 2023|publisher=[[European Space Agency]]|access-date=11 June 2023|url-status=live|archive-url=https://web.archive.org/web/20230810132645/https://www.eoportal.org/other-space-activities/iss-matiss|archive-date=10 August 2023|website=eoportal.org}}</ref> The most recent and final experiment of the series was launched on 5 June 2023 aboard the [[SpaceX CRS-28]] cargo mission to ISS, comprising four plaques. Whereas previous experiments in the series were limited to analysis by [[Microscopy|light microsocopy]], this experiment uses quartz glass made of pure silica, which will allow [[Spectroscopy|spectrographic analysis]]. Two of the plaques were returned after eight months and the remaining two after 16 months.<ref name="arstechnica-20230608">{{Cite news|url=https://arstechnica.com/science/2023/06/testing-antibacterial-surfaces-on-the-international-space-station/|title=Testing antibacterial surfaces on the International Space Station|last=Khadilkar|first=Dhananjay|date=8 June 2023|access-date=11 June 2023|url-status=live|archive-url=https://web.archive.org/web/20231108032832/https://arstechnica.com/science/2023/06/testing-antibacterial-surfaces-on-the-international-space-station/|archive-date=8 November 2023|work=[[Ars Technica]]}}</ref>

In April 2019, NASA reported that a comprehensive study had been conducted into the microorganisms and fungi present on the ISS. The experiment was performed over a period of 14 months on three different flight missions, and involved taking samples from 8 predefined locations inside the station, then returning them to earth for analysis. In prior experiments, analysis was limited to culture-based methods, thus overlooking microbes which cannot be grown in culture. The present study used [[Molecular diagnostics|molecular]]-based methods in addition to culturing, resulting in a more complete catalog. The results may be useful in improving the health and safety conditions for astronauts, as well as better understanding other closed-in environments on Earth such as clean rooms used by the pharmaceutical and medical industries.<ref name="EA-20190407">{{Cite press release|url=https://www.biomedcentral.com/about/press-centre/science-press-releases/08-04-19|title=NASA researchers catalogue all microbes and fungi on the International Space Station|last=Korn|first=Anne|date=7 April 2019|publisher=[[BioMed Central]]|access-date=30 August 2021|url-status=live|archive-url=https://web.archive.org/web/20230810131751/https://www.biomedcentral.com/about/press-centre/science-press-releases/08-04-19|archive-date=10 August 2023}}</ref><ref name="MBJ-20190408">{{Cite journal|last=Sielaff|first=Aleksandra Checinska|display-authors=et al.|date=8 April 2019|title=Characterization of the total and viable bacterial and fungal communities associated with the International Space Station surfaces|journal=Microbiome|volume=7|issue=50|page=50|doi=10.1186/s40168-019-0666-x|pmc=6452512|pmid=30955503|doi-access=free}}</ref>

====Noise====
Space flight is not inherently quiet, with noise levels exceeding acoustic standards as far back as the [[Apollo missions]].<ref>{{Cite book|last1=Limardo|first1=José G.|last2=Allen|first2=Christopher S.|last3=Danielson|first3=Richard W.|title=43rd International Conference on Environmental Systems|chapter=Assessment of Crewmember Noise Exposures on the International Space Station|date=14 July 2013|location=Vail, Colorado|publisher=American Institute of Aeronautics and Astronautics|doi=10.2514/6.2013-3516|isbn=978-1-62410-215-8}}</ref><ref>{{Cite journal|last1=Nakashima|first1=Ann|last2=Limardo|first2=José|last3=Boone|first3=Andrew|last4=Danielson|first4=Richard W.|date=31 January 2020|title=Influence of impulse noise on noise dosimetry measurements on the International Space Station|journal=International Journal of Audiology|volume=59|issue=sup1|pages=S40–S47|doi=10.1080/14992027.2019.1698067|issn=1499-2027|pmid=31846378|s2cid=209407363|doi-access=free}}</ref> For this reason, NASA and the International Space Station international partners have developed [[noise control]] and [[hearing loss]] prevention goals as part of the health program for crew members. Specifically, these goals have been the primary focus of the ISS Multilateral Medical Operations Panel (MMOP) Acoustics Subgroup since the first days of ISS assembly and operations.<ref name="MMOP_SSP_50260">{{cite web|date=May 2003|title=International Space Station Medical Operations Requirements Documents (ISS MORD), SSP 50260 Revision B|url=http://emits.sso.esa.int/emits-doc/ESTEC/AO6216-SoW-RD9.pdf|url-status=live|archive-url=https://web.archive.org/web/20200220193031/http://emits.sso.esa.int/emits-doc/ESTEC/AO6216-SoW-RD9.pdf|archive-date=20 February 2020|website=emits.sso.esa.int|publisher=NASA}}</ref><ref name="iss-acoustics">{{Cite conference|last1=Allen|first1=Christopher S.|last2=Denham|first2=Samuel A.|date=17 July 2011|title=International Space Station Acoustics – A Status Report|url=https://ntrs.nasa.gov/api/citations/20100039608/downloads/20100039608.pdf|conference=International Conference on Environmental Systems|location=Portland, Oregon|id=JSC-CN-24071 / JSC-CN-22173|archive-url=https://web.archive.org/web/20231118185324/https://ntrs.nasa.gov/api/citations/20100039608/downloads/20100039608.pdf|archive-date=18 November 2023|hdl-access=free|url-status=live|hdl=2060/20150010438|website=ntrs.nasa.gov}}</ref> The effort includes contributions from [[Acoustical engineering|acoustical engineers]], [[audiologists]], [[industrial hygienists]], and physicians who comprise the subgroup's membership from NASA, Roscosmos, the European Space Agency (ESA), the Japanese Aerospace Exploration Agency (JAXA), and the Canadian Space Agency (CSA).

When compared to terrestrial environments, the noise levels experienced by astronauts and cosmonauts on the ISS may seem insignificant and typically occur at levels that would not be of major concern to the [[Occupational Safety and Health Administration]] – rarely reaching 85 dBA. But crew members are exposed to these levels 24 hours a day, seven days a week, with current missions averaging six months in duration. These levels of noise also impose risks to crew health and performance in the form of sleep interference and communication, as well as reduced alarm [[Hearing|audibility]].

Over the 19 plus year history of the ISS, significant efforts have been put forth to limit and reduce noise levels on the ISS. During design and pre-flight activities, members of the Acoustic Subgroup have written acoustic limits and verification requirements, consulted to design and choose the quietest available payloads, and then conducted acoustic verification tests prior to launch.<ref name=MMOP_SSP_50260 />{{rp|5.7.3}} During spaceflights, the Acoustics Subgroup has assessed each ISS module's in flight sound levels, produced by a large number of vehicle and science experiment noise sources, to assure compliance with strict acoustic standards. The acoustic environment on ISS changed when additional modules were added during its construction, and as additional spacecraft arrive at the ISS. The Acoustics Subgroup has responded to this dynamic operations schedule by successfully designing and employing acoustic covers, absorptive materials, [[noise barrier]]s, and vibration isolators to reduce noise levels. Moreover, when pumps, fans, and ventilation systems age and show increased noise levels, this Acoustics Subgroup has guided ISS managers to replace the older, noisier instruments with quiet fan and pump technologies, significantly reducing [[ambient noise level]]s.

NASA has adopted most-conservative damage risk criteria (based on recommendations from the [[National Institute for Occupational Safety and Health]] and the [[World Health Organization]]), in order to protect all crew members. The MMOP Acoustics Subgroup has adjusted its approach to managing noise risks in this unique environment by applying, or modifying, terrestrial approaches for hearing loss prevention to set these conservative limits. One innovative approach has been NASA's Noise Exposure Estimation Tool (NEET), in which noise exposures are calculated in a task-based approach to determine the need for [[hearing protection device]]s (HPDs). Guidance for use of HPDs, either mandatory use or recommended, is then documented in the Noise Hazard Inventory, and posted for crew reference during their missions. The Acoustics Subgroup also tracks spacecraft noise exceedances, applies [[engineering controls]], and recommends hearing protective devices to reduce crew noise exposures. Finally, hearing thresholds are monitored on-orbit, during missions.

There have been no persistent mission-related hearing threshold shifts among US Orbital Segment crewmembers (JAXA, CSA, ESA, NASA) during what is approaching 20 years of ISS mission operations, or nearly 175,000 work hours. In 2020, the MMOP Acoustics Subgroup received the [[Safe-In-Sound Award]] for Innovation for their combined efforts to mitigate any health effects of noise.<ref>{{cite web|year=2020|title=Safe in Sound Winners|url=https://www.safeinsound.us/winners.html|url-status=live|archive-url=https://web.archive.org/web/20200625051514/https://www.safeinsound.us/winners.html|archive-date=25 June 2020|website=safeinsound.us}}</ref>

====Fire and toxic gases====
An onboard fire or a toxic gas leak are other potential hazards. Ammonia is used in the external radiators of the station and could potentially leak into the pressurised modules.<ref>{{Cite AV media|url=https://www.youtube.com/watch?v=doN4t5NKW-k|title=Departing Space Station Commander Provides Tour of Orbital Laboratory|date=3 July 2015|last=Williams|first=Suni (presenter)|publisher=NASA|time=18.00–18.17|access-date=1 September 2019|quote=And some of the things we have to worry about in space are fire ... or if we had some type of toxic atmosphere. We use ammonia for our radiators so there is a possibility that ammonia could come into the vehicle.|medium=video|archive-date=14 August 2021|archive-url=https://web.archive.org/web/20210814155134/https://www.youtube.com/watch?v=doN4t5NKW-k|url-status=live}}</ref>