View source for Medicine:Space medicine

{{Short description|For health conditions encountered during spaceflight}}
[[File:NASA Medical Monitoring 2.jpg|thumb|Dan Burbank and Anton Shkaplerov participate in a medical contingency drill in the Destiny laboratory of the International Space Station. This drill gives crew members the opportunity to work as a team in resolving a simulated medical emergency on board the space station.<ref name="ISS Medical 2013">{{cite web | url=http://www.nasa.gov/mission_pages/station/research/experiments/1025.html | title=International Space Station Medical Monitoring (ISS Medical Monitoring) | date=3 December 2013 | access-date=January 13, 2014 }}</ref>]]
'''Space medicine''' is an area in aerospace medicine that focuses on the medical care of [[Astronaut|astronaut]]s and spaceflight participants. The spaceflight environment poses many unique stressors to the human body, including [[Physics:G-force|G forces]], [[Physics:Micro-g environment|microgravity]], unusual atmospheres such as low pressure or high carbon dioxide, and [[Astronomy:Health threat from cosmic rays|space radiation]]. Space medicine applies space physiology, preventive medicine, primary care, emergency medicine, acute care medicine, austere medicine, public health, and toxicology to prevent and treat medical problems in space. This expertise is additionally used to inform vehicle systems design to minimize the risk to human health and performance while meeting mission objectives.

[[Astronomy:Astronautical hygiene|Astronautical hygiene]] is the application of science and technology to the prevention or control of exposure to the hazards that may cause astronaut ill health.  Both these sciences work together to ensure that astronauts work in a safe environment. Medical consequences such as possible [[Medicine:Blindness|visual impairment]] and [[Medicine:Osteoporosis|bone loss]] have been associated with [[Astronomy:Human spaceflight|human spaceflight]].<ref name="NYT-20140127">{{cite news |last=Chang |first=Kenneth |title=Beings Not Made for Space |url=https://www.nytimes.com/2014/01/28/science/bodies-not-made-for-space.html |date=January 27, 2014 |work={{wipe|New York Times}} |access-date=January 27, 2014 }}</ref><ref name="Wired-20120723">{{cite magazine |last=Mann |first=Adam |title=Blindness, Bone Loss, and Space Farts: Astronaut Medical Oddities |magazine=Wired |url=https://www.wired.com/wiredscience/2012/07/medicine-psychology-space/ |date=July 23, 2012 |access-date=July 23, 2012 }}</ref>

In October 2015, the NASA Office of Inspector General issued a [[Astronomy:Effect of spaceflight on the human body|health hazards report]] related to [[Astronomy:Space exploration|space exploration]], including a [[Astronomy:Human mission to Mars|human mission to Mars]].<ref name="AP-20151029">{{cite news |last=Dunn |first=Marcia |title=Report: NASA needs better handle on health hazards for Mars |url=http://apnews.excite.com/article/20151029/us-sci-space-travel-health-6dfd5b2c76.html |date=October 29, 2015 |work=AP News |access-date=October 30, 2015 }}</ref><ref name="NASA-20151029oig">{{cite web |author=Staff |title=NASA's Efforts to Manage Health and Human Performance Risks for Space Exploration (IG-16-003) |url=https://oig.nasa.gov/audits/reports/FY16/IG-16-003.pdf |date=October 29, 2015 |work=[[Organization:NASA|NASA]] |access-date=October 29, 2015 }}</ref>

== History ==
Hubertus Strughold (1898–1987), a former Nazi physician and physiologist, was brought to the {{wipe|United States}} after [[Social:World War II|World War II]] as part of Operation Paperclip.<ref>{{cite news |url=http://news.bbc.co.uk/1/hi/magazine/4443934.stm |title=Project Paperclip: Dark side of the Moon |date=21 November 2005 |author=Andrew Walker |publisher=BBC News |access-date=2012-04-25 }}</ref> He first coined the term "space medicine" in 1948 and was the first and only Professor of Space Medicine at the School of Aviation Medicine (SAM) at {{wipe|Randolph Air Force Base}}, {{wipe|Texas}}. In 1949, Strughold was made director of the Department of Space Medicine at the SAM (which is now the US Air Force School of Aerospace Medicine (USAFSAM) at Wright-Patterson Air Force Base, Ohio. He played an important role in developing the [[Engineering:Pressure suit|pressure suit]] worn by early American astronauts. He was a co-founder of the Space Medicine Branch of the [[Organization:Aerospace Medical Association|Aerospace Medical Association]] in 1950. The aeromedical library at Brooks AFB was named after him in 1977, but later renamed because documents from the Nuremberg War Crimes Tribunal linked Strughold to medical experiments in which inmates of the Dachau concentration camp were tortured and killed.<ref>{{cite news | agency=Associated Press | date=2006-05-19 | url=http://www.nbcnews.com/id/12869190 | title=Former Nazi removed from Space Hall of Fame | publisher=NBC News | access-date=2006-05-19}}</ref>

Soviet research into Space Medicine was centered at the Scientific Research Testing Institute of Aviation Medicine (NIIAM).  In 1949, A.M. Vasilevsky, the Minister of Defense of the USSR, gave instructions via the initiative of [[Biography:Sergei Korolev|Sergei Korolev]] to NIIAM to conduct biological and medical research. In 1951, NIIAM began to work on the first research work entitled "Physiological and hygienic substantiation of flight capabilities in special conditions", which formulated the main research tasks, the necessary requirements for pressurized cabins, life support systems, rescue and control and recording equipment. At the Korolev design bureau, they created rockets for lifting animals within 200–250&nbsp;km and 500–600&nbsp;km, and then began to talk about developing artificial satellites and launching a man into space.<ref>{{cite news |url=https://function.mil.ru/news_page/country/more.htm?id=12286600@egNews |title=Russian Space Medicine |date=21 July 2021 |publisher=Russian Military |access-date=2021-07-28 }}</ref>  Then in 1963 the Institute for Biomedical Problems (IMBP) was founded to undertake the study of space medicine.<ref>{{cite news |url=https://siarchives.si.edu/collections/siris_arc_217719 |title=Soviet Space Medicine Video History Collection, 1989 |date=20 July 2021 |publisher=Smithsonian Institution |access-date=2021-07-29 }}</ref>

=== Animal testing ===
Before sending humans, space agencies used animals to study the effects of space travel on the body.<ref name=":0">{{Cite book |title=Herald of the Russian Academy of Sciences |year=2013 |publisher=Pleiades Publishing Ltd|doi=10.1134/11480.1555-6492 }}</ref> After several years of failed animal recoveries, an Aerobee rocket launch in September 1951 was the first safe return of a monkey and a group of mice from near space altitudes.<ref name=":12">{{Cite web |title=This New Ocean - Ch2-3 |url=https://history.nasa.gov/SP-4201/ch2-3.htm |access-date=2022-03-11 |website=history.nasa.gov}}</ref> On 3 November 1957, [[Engineering:Sputnik 2|Sputnik 2]] became the first mission to carry a living animal to space, a dog named [[Engineering:Laika|Laika]]. This flight and others suggested the possibility of safely flying in space within a controlled environment, and provided data on how living beings react to space flight.<ref name=":0" /> Later flights with cameras to observe the animal subjects would show in flight conditions such as high-G and zero-G.<ref name=":12" /> Russian tests yielded more valuable physiological data from the animal tests.<ref name=":12" />

On January 31, 1961, a chimpanzee named [[Astronomy:Ham (chimpanzee)|Ham]] was launched into a [[Engineering:Sub-orbital spaceflight|sub-orbital]] flight aboard a [[Engineering:Mercury-Redstone Launch Vehicle|Mercury-Redstone Launch Vehicle]]. The flight was meant to model the planned mission of astronaut Alan Shepard. The mission planned to reach an altitude of 115 miles, and speeds up to 4400 miles per hour.<ref name="Animals in Space">{{Cite web |title=Animals in Space |url=https://history.nasa.gov/animals.html#:~:text=American%20and%20Russian%20scientists%20utilized,Albert%20I,%20a%20rhesus%20monkey. |access-date=2022-04-15 |website=history.nasa.gov}}</ref> However, the actual flight reached 157 miles and a maximum speed of 5857 miles per hour.<ref name="Animals in Space"/> During flight, Ham experienced 6.6 minutes of [[Physics:Weightlessness|weightlessness]]. After splashing down in the Atlantic Ocean, Ham was recovered by the USS Donner.<ref>{{Cite web |title=This New Ocean - Ch10-3 |url=https://history.nasa.gov/SP-4201/ch10-3.htm |access-date=2022-04-15 |website=history.nasa.gov}}</ref> He suffered only limited injuries during flight, only receiving a bruised nose.<ref name=":02">{{Cite web |date=2007-11-12 |title=October Flashback - National Geographic Magazine |url=http://magma.nationalgeographic.com/ngm/2007-10/flashback.html |access-date=2022-04-15 |archive-url=https://web.archive.org/web/20071112094423/http://magma.nationalgeographic.com/ngm/2007-10/flashback.html |archive-date=2007-11-12 }}</ref> Ham's vital signs were monitored and collected throughout the 16 minute flight, and used to develop life support systems for later human astronauts.<ref name=":02" />

Animal testing in space continues currently, with mice, ants, and other animals regularly being sent to the [[Astronomy:International Space Station|International Space Station]].<ref name=":03">{{Cite web |title=Focus on animal experiments onboard of the ISS |url=https://www.recherche-animale.org/en/focus-animal-experiments-onboard-iss |access-date=2022-04-29 |website=Recherche animale |language=en}}</ref> In 2014, eight ant colonies were sent to the ISS to investigate the group behavior of ants in microgravity. The ISS allows for the investigation of animal behavior without sending them in specifically designed capsules.<ref name=":03" />

=== North American X-15 ===
{{main|Engineering:North American X-15}}

Rocket-powered aircraft North American X-15 provided an early opportunity to study the effects of a near-space environment on human physiology.<ref>{{Cite web |title=This New Ocean - Ch2-3 |url=https://www.hq.nasa.gov/office/pao/History/SP-4201/ch2-3.htm |access-date=2022-03-11 |website=www.hq.nasa.gov}}</ref> At its highest operational speed and altitude, the X-15 provided approximately five minutes of weightlessness. This opportunity allowed for the development of devices to facilitate working in low pressure, high acceleration environments such as pressure suits, and [[Telemetry|telemetering]] systems to collect physiological data.<ref name=":1">{{Cite web |title=This New Ocean - Ch2-2 |url=https://history.nasa.gov/SP-4201/ch2-2.htm |access-date=2022-03-11 |website=history.nasa.gov}}</ref> This data and technologies allowed for better mission planning for future space missions.<ref name=":1" />

=== Project Mercury ===
{{main|Astronomy:Project Mercury}}

Space medicine was a critical factor in the United States human space program, starting with [[Astronomy:Project Mercury|Project Mercury]].<ref name="Mills-1965">{{cite book |last=Link |first=Mae Mills |title=Space Medicine in Project Mercury |url=https://books.google.com/books?id=jT3QAAAAMAAJ |access-date=17 February 2019 |series=NASA SP (Series) |year=1965 |publisher=Scientific and Technical Information Office, National Aeronautics and Space Administration |location=Washington, D.C. |oclc=1084318604 |type=NASA Special Publication |id=NASA SP-4003}}</ref> The main precaution taken by Mercury astronauts to defend against high G environments like launch and reentry was a couch with seat belts to make sure astronauts were not forcibly moved from their position. Additionally, experienced pilots proved to be better able to cope with high G scenarios.<ref name=":12" /> One of the pressing concerns with Project Mercury's mission environment was the isolated nature of the cabin. There were deeper concerns about psychological issues than there were about physiological health effects. Substantial animal testing proved beyond a reasonable doubt to NASA engineers that spaceflight could be done safely provided a climate controlled environment.<ref name=":12" />

=== Project Gemini ===
The [[Astronomy:Project Gemini|Gemini]] program primarily addressed the psychological issues from isolation in space with two crewmembers. Upon returning from space, it was recorded that crewmembers experienced a loss of balance and a decrease in anaerobic ability.<ref name=":2">{{Cite book |last1=Johnston|first1=Richard S. |last2=Dietlein|first2=Lawrence F. |last3=Berry|first3=Charles A. |url=http://worldcat.org/oclc/1222824163 |title=Biomedical results of Apollo |date=1975 |publisher=Scientific and Technical Information Office, National Aeronautics and Space Administration |oclc=1222824163}}</ref>

=== Project Apollo ===
The [[Astronomy:Apollo program|Apollo]] program began with a substantial basis of medical knowledge and precautions from both Mercury and [[Astronomy:Project Gemini|Gemini]]. The understanding of high and low G environments was well documented and the effects of isolation had been addressed with Gemini and Apollo having multiple occupants in one capsule. The primary research of the Apollo Program focused on pre-flight and post-flight monitoring.<ref name=":2" /> Some Apollo mission plans were postponed or altered due to some or all crewmembers contracting a communicable disease. Apollo 14 instituted a form of quarantine for crewmembers so as to curb the passing of typical illnesses.<ref name=":2" /> While the efficacy of the Flight Crew Health Stabilization Program was questionable as some crewmembers still contracted diseases,<ref name=":2" /> the program showed enough results to maintain implementation with current space programs.<ref>{{Cite web |title=Astronauts Enter Quarantine for Upcoming Crew-1 Mission – Commercial Crew Program |url=https://blogs.nasa.gov/commercialcrew/2020/11/03/astronauts-enter-quarantine-for-upcoming-crew-1-mission/ |access-date=2022-04-29 |website=blogs.nasa.gov |language=en-US}}</ref>

== Effects of space-travel ==
[[File:Space body fluid.svg|thumb|400px|The effects of microgravity on fluid distribution around the body (greatly exaggerated) ''(NASA)'']]
{{Main|Astronomy:Effect of spaceflight on the human body}}
In October 2018, [[Organization:NASA|NASA]]-funded researchers found that lengthy journeys into [[Astronomy:Outer space|outer space]], including travel to the [[Astronomy:Mars|planet Mars]], may substantially damage the  [[Biology:Gastrointestinal tract|gastrointestinal tissues]] of astronauts. The studies support earlier work that found such journeys could significantly damage the [[Biology:Brain|brain]]s of [[Astronaut|astronaut]]s, and age them prematurely.<ref name="TI-20181002">{{cite news |last=Griffin |first=Andrew |title=Travelling to Mars and deep into space could kill astronauts by destroying their guts, finds Nasa-funded study – Previous work has shown that astronauts could age prematurely and have damaged brain tissue after long journeys |url=https://www.independent.co.uk/news/science/nasa-mars-deep-space-journey-guts-gi-digestive-animal-study-gastrointestinal-health-a8563926.html |archive-url=https://ghostarchive.org/archive/20220524/https://www.independent.co.uk/news/science/nasa-mars-deep-space-journey-guts-gi-digestive-animal-study-gastrointestinal-health-a8563926.html |archive-date=2022-05-24 |url-access=subscription |url-status=live |date=2 October 2018 |work=The Independent |access-date=2 October 2018 }}</ref>

In November 2019, researchers reported that [[Astronaut|astronaut]]s experienced serious [[Physics:Hemodynamics|blood flow]] and [[Medicine:Thrombus|clot]] problems while on board the International Space Station, based on a six-month study of 11 healthy astronauts. The results may influence long-term [[Engineering:Spaceflight|spaceflight]], including a mission to the planet [[Astronomy:Mars|Mars]], according to the researchers.<ref name="CNN-20191115">{{cite news |last=Strickland |first=Ashley |title=Astronauts experienced reverse blood flow and blood clots on the space station, study says |url=https://www.cnn.com/2019/11/15/health/astronaut-blood-flow-clot-scn-trnd/index.html |date=15 November 2019 |work=CNN News |access-date=22 November 2019 }}</ref><ref name="JAMA-20191113">{{cite journal |author=Marshall-Goebel, Karina |display-authors=et al. |title=Assessment of Jugular Venous Blood Flow Stasis and Thrombosis During Spaceflight |date=13 November 2019 |journal=JAMA Network Open |volume=2 |issue=11 |pages=e1915011 |doi=10.1001/jamanetworkopen.2019.15011 |pmid=31722025 |doi-access=free |pmc=6902784 }}</ref>

=== Blood clots ===
Deep vein thrombosis of the internal jugular vein of the neck was first discovered in 2020 in an astronaut on a long duration stay on the ISS, requiring treatment with blood thinners.<ref>{{Cite web |last=David |first=Leonard |date=2020-01-03 |title=An Astronaut Got a Blood Clot in Space. Here's How Doctors on Earth Fixed It. |url=https://www.space.com/astronaut-suffers-blood-clot-on-space-station.html |access-date=2023-12-30 |website=Space.com |language=en}}</ref> A subsequent study of eleven astronauts found slowed blood flow in the neck veins and even reversal of blood flow in two of the astronauts.<ref>{{Cite web |last=Care |first=University of North Carolina Health |title=Blood clot expert working with NASA to study blood flow, clot formation in zero gravity |url=https://phys.org/news/2022-05-blood-clot-expert-nasa-formation.html |access-date=2023-12-30 |website=phys.org |language=en}}</ref> NASA is currently conducting more research to study whether these abnormalities could predispose astronauts to blood clots. 

=== Cardiac rhythms ===
{{Main|Engineering:Cardiac rhythm problems during space flight}}
Heart rhythm disturbances have been seen among astronauts.<ref>Platts, S. H., Stenger, M. B., Phillips, T. R., Brown, A. K., Arzeno, N. M., Levine, B., & Summers, R. (2009). Evidence Based Review: Risk of Cardiac Rhythm Problems During Spaceflight.</ref> Most of these have been related to [[Medicine:Cardiovascular disease|cardiovascular disease]], but it is not clear whether this was due to pre-existing conditions or [[Astronomy:Effect of spaceflight on the human body|effects of space flight]]. It is hoped that advanced screening for coronary disease has greatly mitigated this risk. Other heart rhythm problems, such as [[Medicine:Atrial fibrillation|atrial fibrillation]], can develop over time, necessitating periodic screening of crewmembers’ heart rhythms. Beyond these terrestrial heart risks, some concern exists that prolonged exposure to microgravity may lead to heart rhythm disturbances. Although this has not been observed to date, further surveillance is warranted.

=== Decompression illness in spaceflight ===
In space, astronauts use a [[Astronomy:Space suit|space suit]], essentially a self-contained individual spacecraft, to do spacewalks, or extra-vehicular activities (EVAs). Spacesuits are generally inflated with 100% [[Chemistry:Oxygen|oxygen]] at a total pressure that is less than a third of normal [[Physics:Atmospheric pressure|atmospheric pressure]].  Eliminating inert atmospheric components such as [[Chemistry:Nitrogen|nitrogen]] allows the astronaut to breathe comfortably, but also have the mobility to use their hands, arms, and legs to complete required work, which would be more difficult in a higher pressure suit.

After the astronaut dons the spacesuit, air is replaced by 100% oxygen in a process called a "nitrogen purge". In order to reduce the risk of [[Medicine:Decompression sickness|decompression sickness]], the astronaut must spend several hours "pre-breathing" at an intermediate nitrogen [[Physics:Partial pressure|partial pressure]], in order to let their body tissues [[Physics:Outgassing|outgas]] nitrogen slowly enough that bubbles are not formed. When the astronaut returns to the "shirt sleeve" environment of the spacecraft after an EVA, pressure is restored to whatever the operating pressure of that spacecraft may be, generally normal atmospheric pressure. Decompression illness in spaceflight consists of decompression sickness (DCS) and other injuries due to uncompensated changes in pressure, or [[Medicine:Barotrauma|barotrauma]].

==== Decompression sickness ====
[[Medicine:Decompression sickness|Decompression sickness]] is the injury to the tissues of the body resulting from the presence of nitrogen bubbles in the tissues and blood. This occurs due to a rapid reduction in ambient pressure causing the dissolved nitrogen to come out of solution as gas bubbles within the body.<ref>{{cite journal | last = Ackles | first = KN | title = Blood-Bubble Interaction in Decompression Sickness | journal = Defence R&D Canada (DRDC) Technical Report | volume = DCIEM-73-CP-960 | year = 1973 | url = http://archive.rubicon-foundation.org/3867 | archive-url = https://web.archive.org/web/20090821164836/http://archive.rubicon-foundation.org/3867 | url-status = usurped | archive-date = August 21, 2009 | access-date =23 May 2010 }}</ref> In space the risk of DCS is significantly reduced by using a technique to wash out the nitrogen in the body's tissues. This is achieved by breathing 100% oxygen for a specified period of time before donning the spacesuit, and is continued after a nitrogen purge.<ref>{{Cite web | url = http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts115/interview_tanner.html | title = Preflight Interview: Joe Tanner | first = Amiko | last = Nevills | publisher = NASA | year = 2006 | access-date = 26 June 2010 | archive-date = 12 May 2013 | archive-url = https://web.archive.org/web/20130512135522/http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts115/interview_tanner.html | url-status = dead }}</ref><ref>{{Cite journal | last1 = Webb | first1 = James T | last2 = Olson | first2 = RM | last3 = Krutz | first3 = RW | last4 = Dixon | first4 = G | last5 = Barnicott | first5 = PT | title = Human tolerance to 100% oxygen at 9.5 psia during five daily simulated 8-hour EVA exposures | journal = Aviation, Space, and Environmental Medicine | volume = 60 | issue = 5 | pages = 415–21 | year = 1989 | pmid = 2730484 | doi=10.4271/881071}}</ref> DCS may result from inadequate or interrupted pre-oxygenation time, or other factors including the astronaut's level of hydration, physical conditioning, prior injuries and age. Other risks of DCS include inadequate nitrogen purge in the EMU, a strenuous or excessively prolonged EVA, or a loss of suit pressure. Non-EVA crewmembers may also be at risk for DCS if there is a loss of spacecraft cabin pressure.

Symptoms of DCS in space may include chest pain, shortness of breath, cough or pain with a deep breath, unusual fatigue, lightheadedness, dizziness, headache, unexplained musculoskeletal pain, tingling or numbness, extremities weakness, or visual abnormalities.<ref>{{cite book  | last1 = Francis  | first1 = T James R  | last2 = Mitchell  | first2 = Simon J  |  year = 2003  | chapter = 10.6: Manifestations of Decompression Disorders  | pages = 578–584  | editor1-last = Brubakk  | editor1-first = Alf O  | editor2-last = Neuman  | editor2-first = Tom S  | title = Bennett and Elliott's physiology and medicine of diving  | edition = 5th Revised  | publisher = Saunders  | location = United States  | oclc = 51607923  | isbn = 978-0-7020-2571-6 }}</ref>

Primary treatment principles consist of in-suit repressurization to re-dissolve nitrogen bubbles,<ref>{{cite journal | last1 = Berghage | first1 = Thomas E | first2 = James | last2 = Vorosmarti Jr | first3 = EEP | last3 = Barnard | title = Recompression treatment tables used throughout the world by government and industry | journal = US Naval Medical Research Center Technical Report | volume = NMRI-78-16 | year = 1978 | url = http://archive.rubicon-foundation.org/3414 | archive-url = https://web.archive.org/web/20090805032550/http://archive.rubicon-foundation.org/3414 | url-status = usurped | archive-date = August 5, 2009 | access-date =25 May 2010 }}</ref> 100% oxygen to re-oxygenate tissues,<ref>{{cite book  | last = Marx  | first = John  | year = 2010  | title = Rosen's emergency medicine: concepts and clinical practice  | edition = 7th  | publisher = Mosby/Elsevier  | location = Philadelphia, PA  | isbn = 978-0-323-05472-0}}</ref> and hydration to improve the circulation to injured tissues.<ref>{{cite web|url=http://www.diversalertnetwork.org/medical/articles/article.asp?articleid=65 |title=Decompression Illness: What Is It and What Is The Treatment? |last=Thalmann |first=Edward D |publisher=Divers Alert Network |date=March–April 2004 |access-date=3 August 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100613064055/http://diversalertnetwork.org/medical/articles/article.asp?articleid=65 |archive-date=13 June 2010 |df=dmy }}</ref>

==== Barotrauma ====
[[Medicine:Barotrauma|Barotrauma]] is the injury to the tissues of air filled spaces in the body as a result of differences in pressure between the body spaces and the ambient atmospheric pressure. Air filled spaces include the middle ears, paranasal sinuses, lungs and gastrointestinal tract.<ref>{{cite book |title=US Navy Diving Manual, 6th revision |year=2006 |publisher=US Naval Sea Systems Command |location=United States |url=http://www.supsalv.org/00c3_publications.asp?destPage=00c3&pageID=3.9 |access-date=2008-05-26 |archive-date=2008-05-02 |archive-url=https://web.archive.org/web/20080502023541/http://www.supsalv.org/00c3_publications.asp?destPage=00c3&pageId=3.9 |url-status=dead }}</ref><ref name="usn">{{cite book |title=Bennett and Elliott's physiology and medicine of diving, 5th Rev ed. |last1=Brubakk |first1=A. O. |first2=T. S. |last2=Neuman |year=2003 |publisher=Saunders Ltd. |location=United States |isbn=978-0-7020-2571-6 |pages=800 }}</ref> One would be predisposed by a pre-existing upper respiratory infection, nasal allergies, recurrent changing pressures, dehydration, or a poor equalizing technique.

Positive pressure in the air filled spaces results from reduced barometric pressure during the depressurization phase of an EVA.<ref>{{cite journal | author = Vogt L. |others= Wenzel J., Skoog A. I., Luck S., Svensson B. | year = 1991 | title = European EVA decompression sickness risks | journal = Acta Astronautica | volume = 23 | pages = 195–205 | doi = 10.1016/0094-5765(91)90119-p | pmid = 11537125 | bibcode = 1991AcAau..23..195V }}</ref><ref>Newman, D., & Barrat, M. (1997). Life support and performance issues for extravehicular activity (EVA). Fundamentals of Space Life Sciences, 2.</ref> It can cause abdominal distension, ear or sinus pain, decreased hearing, and dental or jaw pain.<ref name=usn/><ref>{{cite journal |last1=Robichaud |first1=R. |last2=McNally |first2=M. E. |title=Barodontalgia as a differential diagnosis: symptoms and findings |journal=Journal of the Canadian Dental Association |volume=71 |issue=1 |pages=39–42 |date = January 2005|pmid=15649340 |url=http://www.cda-adc.ca/jcda/vol-71/issue-1/39.html |access-date=2008-07-19}}</ref> Abdominal distension can be treated with extending the abdomen, gentle massage and encourage passing flatus. Ear and sinus pressure can be relieved with passive release of positive pressure.<ref name=pp/> Pretreatment for susceptible individuals can include oral and nasal [[Chemistry:Decongestant|decongestant]]s, or oral and nasal [[Biology:Steroid|steroid]]s.<ref name=med/>

Negative pressure in air fill spaces results from increased barometric pressure during repressurization after an EVA or following a planned restoration of a reduced cabin pressure. Common symptoms include ear or sinus pain, decreased hearing, and tooth or jaw pain.<ref>Clark, J. B. (2008). Decompression-related disorders: pressurization systems, barotrauma, and altitude sickness. In Principles of Clinical Medicine for Space Flight (pp. 247–271). Springer, New York, NY.</ref>

Treatment may include active positive pressure equalization of ears and sinuses,<ref>{{cite journal | author = Hidir Y. |others=Ulus S., Karahatay S., Satar B. | year = 2011 | title = A comparative study on efficiency of middle ear pressure equalization techniques in healthy volunteers | journal = Auris Nasus Larynx | volume = 38 | issue = 4| pages = 450–455 | doi = 10.1016/j.anl.2010.11.014 | pmid = 21216116 }}</ref><ref name="pp">{{cite web|url=http://staff.washington.edu/ekay/MEbaro.html#BTV|title=Prevention of middle ear barotrauma|last=Kay|first=E|year=2000|work=Doc's Diving Medicine|publisher=staff.washington.edu|access-date=13 January 2017|archive-date=16 January 2017|archive-url=https://web.archive.org/web/20170116144243/http://staff.washington.edu/ekay/MEbaro.html#BTV|url-status=dead}}</ref> oral and nasal decongestants, or oral and nasal steroids, and appropriate pain medication if needed.<ref name="med">{{cite web|title=Barotrauma Medication |url=http://emedicine.medscape.com/article/768618-medication |first=Joseph |last=Kaplan |editor-first=Joe |editor-last=Alcock |website=emedicine.medscape.com |access-date=15 January 2017}}</ref>

=== Decreased immune system functioning ===
Astronauts in space have weakened immune systems, which means that in addition to increased vulnerability to new exposures, viruses already present in the body—which would normally be suppressed—become active.<ref>{{cite journal | author = Pierson D.L. |others= Stowe R.P., Phillips T.M., Lugg D.J., Mehta S.K. | year = 2005 | title = Epstein–Barr virus shedding by astronauts during space flight | journal = Brain, Behavior, and Immunity | volume = 19 | issue = 3| pages = 235–242 | doi = 10.1016/j.bbi.2004.08.001 | pmid = 15797312 | s2cid = 24367925 }}</ref> In space, T-cells do not reproduce properly, and the cells that do exist are less able to
fight off infection.<ref>{{cite journal | author = Cogoli A | year = 1996 | title = Gravitational physiology of human immune cells: a review of in vivo, ex vivo and in vitro studies | journal = Journal of Gravitational Physiology | volume = 3 | issue = 1| pages = 1–9 | pmid = 11539302 }}</ref> NASA research is measuring the change in the immune systems of its astronauts as well as performing experiments with T-cells in space.

On April 29, 2013, scientists in Rensselaer Polytechnic Institute, funded by [[Organization:NASA|NASA]], reported that, during [[Engineering:Spaceflight|spaceflight]] on the [[Astronomy:International Space Station|International Space Station]], microbes seem to adapt to the [[Astronomy:Space environment|space environment]] in ways "not observed on Earth" and in ways that "can lead to increases in growth and [[Biology:Virulence|virulence]]".<ref name="PLos-20130429">{{cite journal  |vauthors=Kim W, etal |title=Spaceflight Promotes Biofilm Formation by Pseudomonas aeruginosa |date=April 29, 2013 |journal=PLOS ONE |volume=8 |issue=4 |page=e6237 |doi=10.1371/journal.pone.0062437 |pmid=23658630 |pmc=3639165 |bibcode = 2013PLoSO...862437K |doi-access=free }}</ref>

In March 2019, NASA reported that latent [[Biology:Virus|virus]]es in humans may be activated during [[Astronomy:Human spaceflight|space missions]], adding possibly more risk to astronauts in future deep-space missions.<ref name="EA-20190315">{{cite news |author=Staff |title=Dormant viruses activate during spaceflight -- NASA investigates - The stress of spaceflight gives viruses a holiday from immune surveillance, putting future deep-space missions in jeopardy |url=https://www.eurekalert.org/pub_releases/2019-03/f-dva031519.php |date=15 March 2019 |work=EurekAlert! |access-date=16 March 2019 }}</ref>

=== Increased infection risk ===

A 2006 Space Shuttle experiment found that ''Salmonella typhimurium'', a bacterium that can cause food poisoning, became more virulent when cultivated in space.<ref name="ASU-20070923">{{cite web |last=Caspermeyer |first=Joe |title=Space flight shown to alter ability of bacteria to cause disease |url=https://biodesign.asu.edu/news/space-flight-shown-alter-ability-bacteria-cause-disease |date=23 September 2007 |work=[[Organization:Arizona State University|Arizona State University]] |access-date=14 September 2017 |archive-date=14 September 2017 |archive-url=https://web.archive.org/web/20170914172718/https://biodesign.asu.edu/news/space-flight-shown-alter-ability-bacteria-cause-disease |url-status=dead }}</ref> On April 29, 2013, scientists in Rensselaer Polytechnic Institute, funded by [[Organization:NASA|NASA]], reported that, during [[Engineering:Spaceflight|spaceflight]] on the [[Astronomy:International Space Station|International Space Station]], microbes seem to adapt to the [[Astronomy:Space environment|space environment]] in ways "not observed on Earth" and in ways that "can lead to increases in growth and [[Biology:Virulence|virulence]]".<ref name="PLos-20130429" /> More recently, in 2017, [[Biology:Bacteria|bacteria]] were found to be more resistant to [[Chemistry:Antibiotic|antibiotic]]s and to thrive in the near-weightlessness of space.<ref name="GZM-20170913">{{cite web |last=Dvorsky |first=George |title=Alarming Study Indicates Why Certain Bacteria Are More Resistant to Drugs in Space |url=https://gizmodo.com/alarming-study-indicates-why-certain-bacteria-are-more-1805666249 |date=13 September 2017 |work=Gizmodo |access-date=14 September 2017 }}</ref> [[Biology:Microorganism|Microorganism]]s have been observed to survive the [[Physics:Vacuum|vacuum]] of outer space.<ref name=Dose>{{cite journal | title=ERA-experiment "space biochemistry" | journal=Advances in Space Research | volume=16 | issue=8 | year= 1995 |pages=119–129 |doi=10.1016/0273-1177(95)00280-R | pmid=11542696| last1=Dose | first1=K. | last2=Bieger-Dose | first2=A. | last3=Dillmann | first3=R. | last4=Gill | first4=M. | last5=Kerz | first5=O. | last6=Klein | first6=A. | last7=Meinert | first7=H. | last8=Nawroth | first8=T. | last9=Risi | first9=S. | last10=Stridde | first10=C. | bibcode=1995AdSpR..16h.119D }}</ref><ref name='Horneck'>{{cite journal | title=Biological responses to space: results of the experiment "Exobiological Unit" of ERA on EURECA I | journal=Adv. Space Res. | year=1995 | author1=Horneck G. |author2=Eschweiler, U. |author3=Reitz, G. |author4=Wehner, J. |author5=Willimek, R. |author6=Strauch, K. | volume=16 | issue=8 | pages=105–18| pmid=11542695 | bibcode=1995AdSpR..16h.105H |doi=10.1016/0273-1177(95)00279-N}}</ref> Researchers in 2018 reported, after detecting the presence on the [[Astronomy:International Space Station|International Space Station]] (ISS) of five ''[[Biology:Enterobacter|Enterobacter bugandensis]]'' bacterial strains, none [[Biology:Pathogen|pathogen]]ic to humans, that [[Biology:Microorganism|microorganism]]s on ISS should be carefully monitored to continue assuring a medically healthy environment for [[Astronaut|astronaut]]s.<ref name="EA-20181122">{{cite web |author=BioMed Central |title=ISS microbes should be monitored to avoid threat to astronaut health |url=https://www.eurekalert.org/pub_releases/2018-11/bc-ims112018.php |date=22 November 2018 |work=EurekAlert! |access-date=25 November 2018 }}</ref><ref name="BMC-20181123">{{cite journal |author=Singh, Nitin K. |display-authors=0 |title=Multi-drug resistant Enterobacter bugandensis species isolated from the International Space Station and comparative genomic analyses with human pathogenic strains |date=23 November 2018 |journal=BMC Microbiology |volume=18 |issue=1 |page=175 |doi=10.1186/s12866-018-1325-2 |pmid=30466389 |pmc=6251167 |doi-access=free }}</ref>

=== Effects of fatigue ===
{{further|Medicine:Fatigue and sleep loss during spaceflight}}
[[Astronomy:Human spaceflight|Human spaceflight]] often requires astronaut crews to endure long periods without rest.   Studies have shown that lack of sleep can cause fatigue that leads to errors while performing critical tasks.<ref name="Harrison 1998">{{cite journal |last1=Harrison |first1=Yvonne |last2=Horne |first2=James |title=Sleep loss impairs short and novel language tasks having a prefrontal focus |journal=Journal of Sleep Research |date=June 1998 |volume=7 |issue=2 |pages=95–100 |doi=10.1046/j.1365-2869.1998.00104.x |pmid=9682180 |s2cid=34980267}}</ref><ref name="Durmer 2005">{{cite journal |last1=Durmer |first1=JS |last2=Dinges |first2=DF |title=Neurocognitive consequences of sleep deprivation. |journal=Seminars in Neurology|date=Mar 2005 |volume=25 |issue=1 |pages=117–29 |pmid=15798944 |pmc=3564638 |url=http://www.med.upenn.edu/uep/user_documents/dfd3.pdf |doi=10.1055/s-2005-867080 |url-status=dead |archive-url=https://web.archive.org/web/20120617024410/http://www.med.upenn.edu/uep/user_documents/dfd3.pdf |archive-date=2012-06-17}}</ref><ref name="Banks 2007">{{cite journal |last1=Banks |first1=S |last2=Dinges |first2=DF |title=Behavioral and physiological consequences of sleep restriction. |journal=Journal of Clinical Sleep Medicine |date=15 August 2007 |volume=3 |issue=5 |pages=519–28 |pmid=17803017 |pmc=1978335 |doi=10.5664/jcsm.26918}}</ref>  Also, individuals who are fatigued often cannot determine the degree of their impairment.<ref>{{cite web |last=Whitmire |first=A.M. |title=Risk of Performance Errors due to Sleep Loss, Circadian Desynchronization, Fatigue, and Work Overload |url=http://humanresearchroadmap.nasa.gov/evidence/reports/Sleep.pdf |work=Human Health and Performance Risks of Space Exploration Missions: Evidence reviewed by the NASA Human Research Program |access-date=17 May 2012 |author2=Leveton, L.B |author3=Barger, L. |author4=Brainard, G. |author5=Dinges, D.F. |author6=Klerman, E. |author7= Shea, C. |page=88}}</ref>
Astronauts and ground crews frequently suffer from the effects of [[Medicine:Sleep deprivation|sleep deprivation]] and [[Biology:Circadian rhythm#Disruption|circadian rhythm disruption]].  Fatigue due to sleep loss, sleep shifting and [[Medicine:Occupational stress|work overload]] could cause performance errors that put space flight participants at risk of compromising mission objectives as well as the health and safety of those on board.

=== Loss of balance ===
Leaving and returning to Earth's gravity causes “space sickness,” dizziness, and loss of balance in astronauts. By studying how changes can affect balance in the human body—involving the senses, the brain, the inner ear, and blood pressure—NASA hopes to develop treatments that can be used on Earth and in space to correct balance disorders. Until then, NASA's astronauts must rely on a medication called [[Chemistry:Midodrine|Midodrine]] (an “anti-dizzy” pill that temporarily increases blood pressure), and/or [[Chemistry:Promethazine|promethazine]] to help carry out the tasks they need to do to return home safely.<ref>{{cite journal | author = Shi S. J. |others= Platts S. H., Ziegler M. G., Meck J. V. | year = 2011 | title = Effects of promethazine and midodrine on orthostatic tolerance | journal = Aviation, Space, and Environmental Medicine | volume = 82 | issue = 1| pages = 9–12 | doi = 10.3357/asem.2888.2011 | pmid = 21235099 }}</ref>

=== Loss of bone density ===
[[Astronomy:Spaceflight osteopenia|Spaceflight osteopenia]] is the bone loss associated with [[Astronomy:Human spaceflight|human spaceflight]].<ref name="Wired-20120723" /> The metabolism of calcium is limited in microgravity and will cause calcium to leak out of bones.<ref name=":0" /> After a 3–4 month trip into space, it takes about 2–3 years to regain lost bone density.<ref>{{cite journal | author = Sibonga J. D. |others= Evans H. J., Sung H. G., Spector E. R., Lang T. F., Oganov V. S., LeBlanc A. D. | year = 2007 | title = Recovery of spaceflight-induced bone loss: bone mineral density after long-duration missions as fitted with an exponential function | journal = Bone | volume = 41 | issue = 6| pages = 973–978 | doi = 10.1016/j.bone.2007.08.022 | pmid = 17931994 | hdl = 2060/20070032016 | hdl-access = free }}</ref><ref>{{cite journal | author = Williams D. |others= Kuipers A., Mukai C., Thirsk R. | year = 2009 | title = Acclimation during space flight: effects on human physiology | journal = Canadian Medical Association Journal | volume = 180 | issue = 13| pages = 1317–1323 | doi = 10.1503/cmaj.090628 | pmid = 19509005 | doi-access = free | pmc = 2696527 }}</ref> New techniques are being developed to help astronauts recover faster. Research in the following areas holds the potential to aid the process of growing new bone:
* Diet and Exercise changes may reduce osteoporosis.
* Vibration Therapy  may stimulate bone growth.<ref>{{cite journal | author = Hawkey A | year = 2007 | title = Low magnitude, high frequency signals could reduce bone loss during spaceflight | journal = Journal of the British Interplanetary Society | volume = 60 | pages = 278–284 | bibcode = 2007JBIS...60..278H }}</ref>
* Medication could trigger the body to produce more of the protein responsible for bone growth and formation.

=== Loss of muscle mass ===
In space, muscles in the legs, back, spine, and heart weaken and waste away because they no longer are needed to overcome gravity, just as people lose muscle when they age due to reduced physical activity.<ref name="Wired-20120723" /> Astronauts rely on research in the following areas to build muscle and maintain body mass:
* Exercise may build muscle if at least two hours a day is spent doing resistance training routines.
* Neuromuscular Electrical Stimulation as a method to prevent muscle atrophy.<ref name=":1" />

=== Impairment of eyesight ===
{{Main|Medicine:Visual impairment due to intracranial pressure}}
During long space flight missions, astronauts may develop ocular changes and visual impairment collectively known as the Space Associated Neuro-ocular Syndrome (SANS).<ref name="NYT-20140127" /><ref name="Wired-20120723" /><ref name="Mader-2011">{{cite journal |author=Mader, T. H.|title=Optic Disc Edema, Globe Flattening, Choroidal Folds, and Hyperopic Shifts Observed in Astronauts after Long-duration Space Flight |url=http://www.aaojournal.org/article/S0161-6420(11)00564-1/abstract |date=2011 |journal=Ophthalmology |volume=118 |issue=10 |pages=2058–2069 |doi=10.1016/j.ophtha.2011.06.021 |pmid=21849212|s2cid=13965518 |display-authors=0}}</ref><ref name="Puiu-20111109">{{cite web |last=Puiu |first=Tibi |title=Astronauts' vision severely affected during long space missions |url=http://www.zmescience.com/medicine/astronaut-eyesight-damage-weightlessness-3214143/ |date=November 9, 2011 |publisher=zmescience.com |access-date=February 9, 2012 }}</ref><ref name="CNN-20120109">{{cite news |url=http://www.cnn.com/video/#/video/us/2012/02/09/pkg-zarrella-astronaut-vision.cnn |title=Male Astronauts Return With Eye Problems (video) |date=9 Feb 2012 |publisher=CNN News |access-date=2012-04-25 }}</ref><ref name="Space-20120313">{{cite web |author=Space Staff |title=Spaceflight Bad for Astronauts' Vision, Study Suggests |url=http://www.space.com/14876-astronaut-spaceflight-vision-problems.html |date=13 March 2012 |publisher=Space.com |access-date=14 March 2012 }}</ref><ref name="Radiology-20120313">{{cite journal |author=Kramer, Larry A.|title=Orbital and Intracranial Effects of Microgravity: Findings at 3-T MR Imaging |journal=Radiology |doi=10.1148/radiol.12111986 |pmid=22416248 |date=13 March 2012 |display-authors=0 |volume=263 |issue=3 |pages=819–827}}</ref><ref name="SKR-20171103">{{cite news |last=Howell |first=Elizabeth |title=Brain Changes in Space Could Be Linked to Vision Problems in Astronauts |url=https://www.seeker.com/space/brain-changes-in-space-could-be-linked-to-vision-problems-in-astronauts |date=3 November 2017 |work=Seeker |access-date=3 November 2017 }}</ref> Such vision problems may be a major concern for future deep space flight missions, including a [[Astronomy:Human mission to Mars|human mission to Mars]].<ref name="Mader-2011" /><ref name="Puiu-20111109" /><ref name="CNN-20120109" /><ref name="Space-20120313" /><ref name="WIRED-20140212">{{cite magazine |last=Fong, MD |first=Kevin |title=The Strange, Deadly Effects Mars Would Have on Your Body |url=https://www.wired.com/opinion/2014/02/happens-body-mars/ |date=12 February 2014 |magazine=Wired |access-date=12 February 2014 }}</ref>

=== Loss of mental abilities and risk of Alzheimer's disease ===
On December 31, 2012, a [[Organization:NASA|NASA]]-supported study reported that [[Astronomy:Human spaceflight|human spaceflight]] may harm the [[Biology:Brain|brain]] of astronauts and accelerate the onset of [[Medicine:Alzheimer's disease|Alzheimer's disease]].<ref name="PLOS-20121231">{{cite journal |last1=Cherry |first1=Jonathan D. |last2=Frost |first2=Jeffrey L. |last3=Lemere |first3=Cynthia A. |last4=Williams |first4=Jacqueline P. |last5=Olschowka |first5=John A. |last6=O'Banion |first6=M. Kerry |title=Galactic Cosmic Radiation Leads to Cognitive Impairment and Increased Aβ Plaque Accumulation in a Mouse Model of Alzheimer's Disease |doi=10.1371/journal.pone.0053275 |volume=7 |number=12 |page=e53275 |journal=PLOS ONE |bibcode = 2012PLoSO...753275C |pmid=23300905 |date=2012 |pmc=3534034|doi-access=free }}</ref><ref name="SpaceRef-20130101">{{cite web |author=Staff |title=Study Shows that Space Travel is Harmful to the Brain and Could Accelerate Onset of Alzheimer's |url=http://spaceref.com/news/viewpr.html?pid=39650 |date=January 1, 2013 |publisher=SpaceRef |access-date=January 7, 2013 |archive-date=May 21, 2020 |archive-url=https://web.archive.org/web/20200521052054/http://spaceref.com/news/viewpr.html?pid=39650%2F |url-status=dead }}</ref><ref name="NasaWatch-20130103">{{cite web |last=Cowing |first=Keith |title=Important Research Results NASA Is Not Talking About (Update) |url=http://nasawatch.com/archives/2013/01/important-resea.html |date=January 3, 2013 |publisher=NASA Watch |access-date=January 7, 2013 }}</ref>

On 2 November 2017, scientists reported that significant changes in the position and structure of the [[Biology:Brain|brain]] have been found in [[Astronaut|astronaut]]s who have taken [[Astronomy:Human spaceflight|trips in space]], based on [[Physics:Magnetic resonance imaging|MRI studies]]. Astronauts who took longer space trips were associated with greater brain changes.<ref name="NEJM-20171102">{{cite journal |author=Roberts, Donna R. |display-authors=0 |title=Effects of Spaceflight on Astronaut Brain Structure as Indicated on MRI |date=2 November 2017 |journal=New England Journal of Medicine |volume=377 |issue=18 |pages=1746–1753 |doi=10.1056/NEJMoa1705129 |pmid=29091569 |s2cid=205102116 |doi-access=free }}</ref><ref name="QTZ-20171103">{{cite web |last=Foley |first=Katherine Ellen |title=Astronauts who take long trips to space return with brains that have floated to the top of their skulls |url=https://qz.com/1119668/space-travel-changes-astronauts-brains/ |date=3 November 2017 |work=Quartz |access-date=3 November 2017 }}</ref>

=== Orthostatic intolerance ===
[[File:Beckman instruments incorp 8049g5371.tiff |right|thumb|The Beckman cardiovascular reflex conditioning system inflated and deflated cuffs in Gemini and Apollo flight suits to stimulate blood flow to lower limbs.<ref>{{cite web |title=Beckman physiological and cardiovascular monitoring system |url=https://digital.sciencehistory.org/works/d217qp53d |website=Science History Institute |access-date=31 July 2019}}</ref>]]
"Under the effects of the earth's [[Physics:Gravity|gravity]], blood and other body fluids are pulled towards the lower body. When gravity is taken away or reduced during space exploration, the blood tends to collect in the upper body instead, resulting in facial [[Medicine:Edema|edema]] and other unwelcome side effects. Upon return to earth, the blood begins to pool in the lower extremities again, resulting in [[Medicine:Orthostatic hypotension|orthostatic hypotension]]."<ref name="Dizzy">{{cite web |url=https://science.nasa.gov/headlines/y2002/25mar_dizzy.htm |title=When Space Makes You Dizzy |date=2002 |publisher=NASA |access-date=2012-04-25 |url-status=dead |archive-url=https://web.archive.org/web/20090826230313/http://science.nasa.gov/headlines/y2002/25mar_dizzy.htm |archive-date=2009-08-26 }}</ref>

In space, astronauts lose fluid volume—including up to 22% of their blood volume. Because it has
less blood to pump, the heart will [[Medicine:Atrophy|atrophy]]. A weakened heart results in low blood pressure
and can produce a problem with “orthostatic tolerance,” or the body's ability to send enough
oxygen to the brain without fainting or becoming dizzy.<ref name="Dizzy"/>

=== Radiation effects ===
[[File:PIA17601-Comparisons-RadiationExposure-MarsTrip-20131209.png|thumb|left|250px|Comparison of Radiation Doses – includes the amount detected on the trip from Earth to Mars by the RAD on the MSL (2011–2013).<ref name="SCI-20130531a">{{cite journal |last=Kerr |first=Richard |title=Radiation Will Make Astronauts' Trip to Mars Even Riskier |date=31 May 2013 |journal=Science |volume=340 |number=6136 |page=1031 |doi=10.1126/science.340.6136.1031 |pmid=23723213 |bibcode=2013Sci...340.1031K}}</ref><ref name="SCI-20130531b">{{cite journal |author=Zeitlin, C.|title=Measurements of Energetic Particle Radiation in Transit to Mars on the Mars Science Laboratory |journal=Science |date=31 May 2013 |volume=340 |number=6136 |pages=1080–1084 |doi=10.1126/science.1235989 |pmid=23723233 |bibcode = 2013Sci...340.1080Z |s2cid=604569 |display-authors=0}}</ref><ref name="NYT-20130530">{{cite news |last=Chang |first=Kenneth |title=Data Point to Radiation Risk for Travelers to Mars |url=https://www.nytimes.com/2013/05/31/science/space/data-show-higher-cancer-risk-for-mars-astronauts.html |date=30 May 2013 |work=New York Times |access-date=31 May 2013 }}</ref><ref name="SN-20130629">{{cite journal |last=Gelling |first=Cristy|title=Mars trip would deliver big radiation dose; Curiosity instrument confirms expectation of major exposures |url=http://www.sciencenews.org/view/generic/id/350728/description/Mars_trip_would_deliver_big_radiation_dose |volume=183 |issue=13 |page=8 |journal=Science News |date=June 29, 2013 |access-date=July 8, 2013 |doi=10.1002/scin.5591831304}}</ref>  ]]

Soviet [[Biography:Cosmonaut|cosmonaut]] [[Biography:Valentin Lebedev|Valentin Lebedev]], who spent 211 days in orbit during 1982 (an absolute record for  stay in Earth's orbit), lost his eyesight to progressive [[Medicine:Cataract|cataract]]. Lebedev stated: “I suffered from a lot of radiation in space. It was all concealed back then, during the Soviet years, but now I can say that I caused damage to my health because of that flight.”<ref name="Wired-20120723" /><ref>{{cite web |url=http://english.pravda.ru/science/earth/17-12-2008/106841-soviet_cosmonaut-0/ |title=Soviet cosmonauts burnt their eyes in space for USSR's glory |date=17 Dec 2008 |publisher=Pravda.Ru |access-date=2012-04-25 }}</ref> On 31 May 2013, NASA scientists reported that a possible [[Astronomy:Human mission to Mars|human mission to Mars]] may involve a great [[Physics:Radiation|radiation risk]] based on the amount of [[Physics:Radiation|energetic particle radiation]] detected by the [[Astronomy:Radiation assessment detector|RAD]] on the [[Organization:Mars Science Laboratory|Mars Science Laboratory]] while traveling from the [[Astronomy:Earth|Earth]] to [[Astronomy:Mars|Mars]] in 2011–2012.<ref name="WIRED-20140212" /><ref name="SCI-20130531a" /><ref name="SCI-20130531b" /><ref name="NYT-20130530" /><ref name="SN-20130629" />

=== Sleep disorders ===

Spaceflight has been observed to disrupt physiological processes that influence sleep patterns in human beings.<ref name="physiology.org">{{Cite journal |last1=Dijk |first1=Derk-Jan |last2=Neri |first2=David F. |last3=Wyatt |first3=James K. |last4=Ronda |first4=Joseph M. |last5=Riel |first5=Eymard |last6=Ritz-De Cecco |first6=Angela |last7=Hughes |first7=Rod J. |last8=Elliott |first8=Ann R. |last9=Prisk |first9=G. Kim |last10=West |first10=John B. |last11=Czeisler |first11=Charles A. |date=2001-11-01 |title=Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights |journal=American Journal of Physiology. Regulatory, Integrative and Comparative Physiology |language=en |volume=281 |issue=5 |pages=R1647–R1664 |doi=10.1152/ajpregu.2001.281.5.R1647 |pmid=11641138 |s2cid=3118573 |issn=0363-6119|doi-access=free }}</ref> Astronauts exhibit asynchronized cortisol rhythmicity, dampened diurnal fluctuations in body temperature, and diminished sleep quality.<ref name="physiology.org"/> Sleep pattern disruption in astronauts is a form of extrinsic (environmentally caused) [[Medicine:Circadian rhythm sleep disorder|circadian rhythm sleep disorder]].<ref name="physiology.org"/>

== Spaceflight analogues ==
Biomedical research in space is expensive and logistically and technically complicated, and thus limited. Conducting medical research in space alone will not provide humans with the depth of knowledge needed to ensure the safety of inter-planetary travelers. Complementary to research in space is the use of spaceflight analogues. Analogues are particularly useful for the study of immunity, sleep, psychological factors, human performance, habitability, and telemedicine. Examples of spaceflight analogues include confinement chambers (Mars-500), sub-aqua habitats ([[Astronomy:NEEMO|NEEMO]]), and Antarctic (Concordia Station) and Arctic FMARS and ([[Astronomy:Haughton–Mars Project|Haughton–Mars Project]]) stations.<ref name="WIRED-20140212" />

== Space medicine careers ==
Physicians in space medicine generally work in operations or research at NASA or, more recently, space companies that are flying private or commercial astronauts or spaceflight participants. 

Operational space medicine provides direct medical support to astronauts and spaceflight participants, conducting medical screening and overseeing their preflight, inflight, and postflight medical care and preparations. As such, operational space medicine physicians are generally physicians trained in a clinical specialty--such as emergency medicine, family medicine, or internal medicine--who have undergone additional residency or fellowship training in aerospace medicine. Board certification in aerospace medicine is the gold standard for physicians who practice operational space medicine.

Research physicians study specific space medical problems, such as the Space Associated Neuro-ocular Syndrome, or focus on medical capabilities for future deep space exploration missions. Research physicians do not have clinical responsibilities in the care of astronauts and thereby are often not specialty-trained in aerospace medicine.

=== Related degrees, areas of specialization, and certifications ===
* Aeromedical certification
* Aerospace medicine
* Aerospace studies
* Occupational and preventive medicine
* Global Health 
* Public Health 
* Disaster medicine
* Prehospital medicine
* Wilderness and extreme medicine

=== Space nursing ===
[[Medicine:Space nursing|Space nursing]] is the [[Medicine:Nursing|nursing]] specialty that studies how [[Astronomy:Human spaceflight|space travel]] impacts human response patterns.  Similar to space medicine, the specialty also contributes to knowledge about nursing care of earthbound patients.<ref>{{cite web|title=Space Nursing Society|url=http://www.spacenursingsociety.net/index.html|access-date=5 December 2011}}</ref><ref>{{cite journal|last=Perrin|first=MM|title=Space nursing. A professional challenge|journal=Nurs Clin North Am|date=Sep 1985|volume=20|issue=3|pages=497–503|doi=10.1016/S0029-6465(22)01894-1 |pmid=3851391|s2cid=252060683 }}</ref>

== Medicine in flight ==
{{further|Medicine:Medical treatment during spaceflight|Astronomy:Sleep in space}}

=== Sleep medicine ===
The use of hypnotic sleep aids is widespread among astronauts, with one 10 year long study finding that 75% and 78% of ISS and space shuttle crew members reported taking such medications while in space.<ref>{{Cite web |date=2014-08-07 |title=Ten-year astronaut sleep study reveals widespread use of sleeping pills in space |url=https://www.pbs.org/newshour/science/ten-year-astronaut-sleep-study-reveals-widespread-use-sleeping-pills-space |access-date=2023-07-17 |website=PBS NewsHour |language=en-us}}</ref> Of astronauts who took hypnotic medications, frequency of use was 52% of all nights. NASA allocates 8.5 hours of 'downtime' for sleep per day for astronauts aboard the ISS, but the average duration of sleep is only 6 hours.<ref>{{Cite journal |last1=Barger |first1=Laura K |last2=Flynn-Evans |first2=Erin E |last3=Kubey |first3=Alan |last4=Walsh |first4=Lorcan |last5=Ronda |first5=Joseph M |last6=Wang |first6=Wei |last7=Wright |first7=Kenneth P |last8=Czeisler |first8=Charles A |date=September 2014 |title=Prevalence of sleep deficiency and use of hypnotic drugs in astronauts before, during, and after spaceflight: an observational study |journal=The Lancet Neurology |language=en |volume=13 |issue=9 |pages=904–912 |doi=10.1016/S1474-4422(14)70122-X |pmc=4188436 |pmid=25127232}}</ref> Poor sleep quality and quantity can compromise the daytime performance and attentiveness of space crew. As such, improving nighttime sleep has been a topic of NASA-funded research for more than half a century.<ref>{{Cite journal |last=Berry |first=C. A. |date=1967-07-24 |title=Space medicine in perspective. A critical review of the manned space program |url=https://pubmed.ncbi.nlm.nih.gov/4383984/ |journal=JAMA |volume=201 |issue=4 |pages=232–241 |doi=10.1001/jama.1967.03130040028009 |issn=0098-7484 |pmid=4383984}}</ref> The following pharmacological and environmental strategies have been investigated in the context of sleep in space:
* Light therapy, involving exposure to visible light at varying intensities and wavelengths to entrain circadian rhythm, is key a topic of interest in NASA-funded research.<ref>{{Cite web |title=Blues Cues {{!}} Harvard Medicine Magazine |url=https://magazine.hms.harvard.edu/articles/blues-cues |access-date=2023-07-17 |website=magazine.hms.harvard.edu |language=en}}</ref> Various photoreceptors in the human eye such as melanopsin, rhodopsin, and photopsin communicate with the [[Biology:Suprachiasmatic nucleus|suprachiasmatic nucleus]] (the master circadian pacemaker of the brain) to entrain circadian rhythm.<ref>{{Cite journal |last1=Paul |first1=Ketema N. |last2=Saafir |first2=Talib B. |last3=Tosini |first3=Gianluca |date=December 2009 |title=The role of retinal photoreceptors in the regulation of circadian rhythms |journal=Reviews in Endocrine and Metabolic Disorders |language=en |volume=10 |issue=4 |pages=271–278 |doi=10.1007/s11154-009-9120-x |issn=1389-9155 |pmc=2848671 |pmid=19777353}}</ref> Melanopsin photoreceptors are most sensitive to blue light wavelengths in the range of 470-490&nbsp;nm (blue light).<ref>{{Cite journal |last1=Enezi |first1=Jazi al |last2=Revell |first2=Victoria |last3=Brown |first3=Timothy |last4=Wynne |first4=Jonathan |last5=Schlangen |first5=Luc |last6=Lucas |first6=Robert |date=August 2011 |title=A "Melanopic" Spectral Efficiency Function Predicts the Sensitivity of Melanopsin Photoreceptors to Polychromatic Lights |journal=Journal of Biological Rhythms |language=en |volume=26 |issue=4 |pages=314–323 |doi=10.1177/0748730411409719 |issn=0748-7304 |pmid=21775290 |s2cid=22369861|doi-access=free }}</ref> NASA has trialed and implemented rhythmic light panels on the ISS to assist entrain the circadian rhythms of astronauts.<ref>{{Citation |title=ScienceCasts: The Power of Light |url=https://www.youtube.com/watch?v=HBtdbaSKexU |access-date=2023-07-17 |language=en}}</ref><ref>{{Cite web |last=Harbaugh |first=Jennifer |date=2016-10-19 |title=Let There Be (Better) Light |url=http://www.nasa.gov/mission_pages/station/research/let-there-be-better-light |access-date=2023-07-17 |website=NASA}}</ref> NASA is soon to test more advanced light panels that change their output light intensity and wavelengths according to time of day, with red-tinted lights (<600&nbsp;nm) set to be used at night to provide visibility at 'night' and shorter wavelengths of high light intensity to be used in the 'morning' or at times where alertness and vigilance are needed.<ref>{{Cite web |title=Circadian Light for ISS |url=https://saga.dk/projects/circadian-light}}</ref><ref>{{Cite web |last=designboom |first=matthew burgos {{!}} |date=2023-03-17 |title=SAGA's multicolored circadian light panel helps astronauts in space beat insomnia |url=https://www.designboom.com/technology/saga-multicolored-circadian-light-panel-astronauts-insomnia-03-17-2023/ |access-date=2023-07-17 |website=designboom {{!}} architecture & design magazine |language=en}}</ref>
*  [[Chemistry:Melatonin|Melatonin]], a naturally occurring hormone secreted by pineal gland, has shown positive effects in reducing sleep latency in orbit.<ref>{{Cite journal |last1=Dijk |first1=D. J. |last2=Neri |first2=D. F. |last3=Wyatt |first3=J. K. |last4=Ronda |first4=J. M. |last5=Riel |first5=E. |last6=Ritz-De Cecco |first6=A. |last7=Hughes |first7=R. J. |last8=Elliott |first8=A. R. |last9=Prisk |first9=G. K. |last10=West |first10=J. B. |last11=Czeisler |first11=C. A. |date=November 2001 |title=Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights |journal=American Journal of Physiology. Regulatory, Integrative and Comparative Physiology |volume=281 |issue=5 |pages=R1647–1664 |doi=10.1152/ajpregu.2001.281.5.R1647 |issn=0363-6119 |pmid=11641138 |s2cid=3118573|doi-access=free }}</ref>
* [[Biology:Nonbenzodiazepine|Nonbenzodiazepine]]s sedative-hypnotics (also known as "z drugs") such as [[Biology:Zolpidem|Zolpidem]] [[Chemistry:Zopiclone|Zopiclone]], and [[Chemistry:Zaleplon|Zaleplon]] are the most frequently used medications on shuttle missions. Despite their widespread use amongst astronauts, relatively little research has been conducted on nonbenzodiazepines in the context of spaceflight. In earthling contexts, nonbenzodiazepines have been shown to produce less residual impairment than benzodiazepines.<ref>{{Cite journal |last=Gunja |first=Naren |date=June 2013 |title=In the Zzz Zone: The Effects of Z-Drugs on Human Performance and Driving |journal=Journal of Medical Toxicology |language=en |volume=9 |issue=2 |pages=163–171 |doi=10.1007/s13181-013-0294-y |issn=1556-9039 |pmc=3657033 |pmid=23456542}}</ref> The shortest acting nonbenzodiazepine, Zaleplon, produces little to no cognitive impairment (at clinically relevant doses) upon waking even when dosed as little as hour before awakening.<ref>{{Cite web |title=Effects of zolpidem and zaleplon on cognitive performance after emergent morning awakenings at Tmax: a randomized placebo-controlled trial |url=https://academic.oup.com/sleep/article/42/3/zsy258/5257338 |access-date=2023-07-17 }}</ref> Research indicates that astronauts frequently take second doses of hypnotic drugs, the shorter duration of action of [[Biology:Nonbenzodiazepine|nonbenzodiazepine]]s have been implicated as being preferable for such situations.<ref name=":3">{{Cite journal |last1=Guo |first1=Jin-Hu |last2=Qu |first2=Wei-Min |last3=Chen |first3=Shan-Guang |last4=Chen |first4=Xiao-Ping |last5=Lv |first5=Ke |last6=Huang |first6=Zhi-Li |last7=Wu |first7=Yi-Lan |date=2014-10-21 |title=Keeping the right time in space: importance of circadian clock and sleep for physiology and performance of astronauts |journal=Military Medical Research |volume=1 |issue=1 |pages=23 |doi=10.1186/2054-9369-1-23 |issn=2054-9369 |pmc=4440601 |pmid=26000169 |doi-access=free }}</ref>
* Benzodiazepines are frequently used medications in space, though less often than [[Biology:Nonbenzodiazepine|nonbenzodiazepine]] "z-drugs".<ref>{{Citation |last1=Ramburrun |first1=Poornima |title=Sleep in Space Environment |date=2022 |url=https://doi.org/10.1007/978-3-030-05526-4_33 |work=Handbook of Space Pharmaceuticals |pages=469–483 |editor-last=Pathak |editor-first=Yashwant V. |access-date=2023-07-17 |place=Cham |publisher=Springer International Publishing |language=en |bibcode=2022hsp..book..469R |doi=10.1007/978-3-030-05526-4_33 |isbn=978-3-030-05526-4 |last2=Ramburrun |first2=Shivani |last3=Choonara |first3=Yahya E. |editor2-last=Araújo dos Santos |editor2-first=Marlise |editor3-last=Zea |editor3-first=Luis}}</ref> The long acting nature of benzodiazepines used by astronauts, such as [[Chemistry:Temazepam|temazepam]], have been labelled "non-ideal" for spaceflight use due to a high tendency of causing morning impairments.<ref name=":3" /> 
* [[Chemistry:Modafinil|Modafinil]], a wakefulness drug, is available on the space station to mitigate the deleterious effects of sleep disruption and "optimise performance while fatigued".<ref>{{Cite journal |last1=Thirsk |first1=R. |last2=Kuipers |first2=A. |last3=Mukai |first3=C. |last4=Williams |first4=D. |date=2009-06-09 |title=The space-flight environment: the International Space Station and beyond |journal=Canadian Medical Association Journal |language=en |volume=180 |issue=12 |pages=1216–1220 |doi=10.1503/cmaj.081125 |issn=0820-3946 |pmc=2691437 |pmid=19487390}}</ref> Modafinil has shown positive results in restoring cognitive function to baseline in the face of total sleep deprivation, though no studies examining modafinil's effects specifically in astronauts have been conducted

=== Ultrasound and space ===

[[Physics:Ultrasound|Ultrasound]] is the main diagnostic imaging tool on ISS and for the foreseeable future missions.  X-rays and [[CT scan]]s involve radiation which is unacceptable in the space environment.  Though [[Physics:Magnetic resonance imaging|MRI]] uses magnetics to create images, it is too large at present to consider as a viable option.  Ultrasound, which uses sound waves to create images and comes in laptop size packages, provides imaging of a wide variety of tissues and organs.  It is currently being used to look at the eyeball and the optic nerve to help determine the cause(s) of changes that NASA has noted mostly in long duration astronauts.  NASA is also pushing the limits of ultrasound use regarding musculoskeletal problems as these are some of the most common and most likely problems to occur.  Significant challenges to using ultrasounds on space missions is training the astronaut to use the equipment (ultrasound technicians spend years in training and developing the skills necessary to be "good" at their job) as well as interpreting the images that are captured.  Much of ultrasound interpretation is done real-time but it is impractical to train astronauts to actually read/interpret ultrasounds.  Thus, the data is currently being sent back to mission control and forwarded to medical personnel to read and interpret.  Future exploration class missions will need to be autonomous due to transmission times taking too long for urgent/emergent medical conditions.  The ability to be autonomous, or to use other equipment such as MRIs, is currently being researched.

=== Space Shuttle era ===

With the additional lifting capability presented by the Space Shuttle program, NASA designers were able to create a more comprehensive medical readiness kit.  The SOMS consists of two separate packages: the Medications and Bandage Kit (MBK) and the Emergency Medical Kit (EMK). While the MBK contained capsulate medications (tablets, capsules, and suppositories), bandage materials, and topical medication, the EMK had medications to be administered by injection, items for performing minor surgeries, diagnostic/therapeutic items, and a microbiological test kit.<ref>{{cite web|last1=Emanuelli|first1=Matteo|title=Evolution of NASA Medical Kits: From Mercury to ISS|url=http://www.spacesafetymagazine.com/spaceflight/space-medicine/evolution-medical-kits-mercury-iss/|publisher=Space Safety Magazine|access-date=28 April 2015|date=2014-03-17}}</ref>

[[Biography:John Glenn|John Glenn]], the first American astronaut to orbit the Earth, returned with much fanfare to space once again on [[Engineering:STS-95|STS-95]] at 77 years of age to confront the physiological challenges preventing long-term space travel for astronauts—loss of bone density, loss of muscle mass, balance disorders, sleep disturbances, cardiovascular changes, and immune system depression—all of which are problems confronting aging people as well as astronauts.<ref>{{cite web|url=https://history.nasa.gov/40thmerc7/glenn.htm|title=John H. Glenn Jr.|last1=Gray|first1=Tara|publisher=NASA History Program Office|access-date=December 9, 2016|url-status=live|archive-url=https://web.archive.org/web/20160128151112/http://history.nasa.gov/40thmerc7/glenn.htm|archive-date=January 28, 2016|df=mdy-all}}</ref>

=== Future investigations ===

==== Feasibility of Long Duration Space Flights ====

In the interest of creating the possibility of longer duration space flight, NASA has invested in the research and application of preventative space medicine, not only for medically preventable pathologies but trauma as well. Although trauma constitutes more of a life-threatening situation, medically preventable pathologies pose more of a threat to astronauts. "The involved crewmember is endangered because of mission stress and the lack of complete treatment capabilities on board the spacecraft, which could result in the manifestation of more severe symptoms than those usually associated with the same disease in the terrestrial environment. Also, the situation is potentially hazardous for the other crewmembers because the small, closed, ecological system of the spacecraft is conducive to disease transmission. Even if the disease is not transmitted, the safety of the other crewmembers may be jeopardized by the loss of the capabilities of the crewmember who is ill. Such an occurrence will be more serious and potentially hazardous as the durations of crewed missions increase and as operational procedures become more complex. Not only do the health and safety of the crewmembers become critical, but the probability of mission success is lessened if the illness occurs during flight. Aborting a mission to return an ill crewmember before mission goals are completed is costly and potentially dangerous."<ref>{{cite journal|last1=Wooley|first1=Bennie|title=Apollo Experience Report- Protection of Life and Health|journal=NASA Technical Note|date=1972|page=20|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720017450.pdf}}</ref>  Treatment of trauma may involve surgery in zero-gravity,<ref>{{Cite web |title=Doctors remove tumour in first zero-g surgery |url=https://www.newscientist.com/article/dn10169-doctors-remove-tumour-in-first-zero-g-surgery/#:~:text=French%20doctors%20carried%20out%20the%20world%E2%80%99s%20first%20ever,tumour%20from%20the%20forearm%20of%20a%2046-year-old%20volunteer.}}</ref> which is a challenging proposition given the need for blood sample containment.  Diagnosis and monitoring of crew members is a particularly vital need.  NASA tested the rHEALTH ONE<ref>{{Cite web |title=rHEALTH ONE flight demonstration |url=https://humanresearchroadmap.nasa.gov/Tasks/task.aspx?i=2431}}</ref> to advance this capability for on-orbit, travel to Moon and Mars.  This capability is mapped to Risk of Adverse Health Outcomes and Decrements in Performance Due to Medical Conditions that occur in Mission, as well as Long Term Health Outcomes Due to Mission Exposures.  Without an approach to perform onboard medical monitoring, loss of crew members may jeopardize long duration missions.

== Impact on science and medicine ==

Astronauts are not the only ones who benefit from space medicine research. Several medical products have been developed that are space spinoffs, which are practical applications for the field of medicine arising out of the space program. Because of joint research efforts between NASA, the National Institutes on Aging (a part of the National Institutes of Health), and other aging-related organizations, space exploration has benefited a particular segment of society, seniors. Evidence of aging related medical research conducted in space was most publicly noticeable during STS-95. These spin-offs are sometimes termed as "exomedicine".

=== Pre-Mercury through Apollo ===
* [[Physics:Radiation therapy|Radiation therapy]] for the treatment of cancer: In conjunction with the Cleveland Clinic, the cyclotron at [[Organization:Glenn Research Center|Glenn Research Center]] in Cleveland, Ohio was used in the first clinical trials for the treatment and evaluation of neutron therapy for cancer patients.<ref>Gahbauer, R., Koh, K. Y., Rodriguez-Antunez, A., Jelden, G. L., Turco, R. F., Horton, J., ... & Roberts, W. (1980). Preliminary results of fast neutron treatments in carcinoma of the pancreas.</ref>
* Foldable [[Engineering:Walker (mobility)|walkers]]: Made from a lightweight metal material developed by NASA for aircraft and spacecraft, foldable walkers are portable and easy to manage.
* Personal alert systems: These are emergency alert devices that can be worn by individuals who may require emergency medical or safety assistance. When a button is pushed, the device sends a signal to a remote location for help. To send the signal, the device relies on telemetry technology developed at NASA.
* CAT and [[Physics:Magnetic resonance imaging|MRI]] scans: These devices are used by hospitals to see inside the [[Medicine:Human body|human body]]. Their development would not have been possible without the technology provided by NASA after it found a way to take better pictures of the Earth's moon.<ref>{{cite journal | author = Goldin D. S. | year = 1995 | title = Keynote address: Second NASA/Uniformed Services University of Health Science International Conference on Telemedicine, Bethesda, Maryland | journal = Journal of Medical Systems | volume = 19 | issue = 1| pages = 9–14 | doi = 10.1007/bf02257185 | pmid = 7790810 | s2cid = 11951292 }}</ref>
* Neuromuscular Electric Stimulation (NMES): A form of treatment originally developed to combat muscle atrophy in space that has been found to have applications outside of space. A prominent example of NMES being used outside of space medicine is muscle stimulator devices for paralyzed individuals. These devices can be used from up to half an hour per day to prevent muscle atrophy in paralyzed individuals.<ref name=":1b">{{Cite journal |last1=Maffiuletti |first1=Nicola A. |last2=Green |first2=David A. |last3=Vaz |first3=Marco Aurelio |last4=Dirks |first4=Marlou L. |date=2019-08-13 |title=Neuromuscular Electrical Stimulation as a Potential Countermeasure for Skeletal Muscle Atrophy and Weakness During Human Spaceflight |journal=Frontiers in Physiology |volume=10 |pages=1031 |doi=10.3389/fphys.2019.01031 |issn=1664-042X |pmc=6700209 |pmid=31456697|doi-access=free }}</ref> It provides electrical stimulation to muscles which is equal to jogging three miles per week. A well-known example is that Christopher Reeve used these in his therapy. Outside of paralyzed individuals, it also has applications in sports medicine, where it is used to manage or prevent potential damages that those high-intensity lifestyles have on athletes.<ref>{{Cite journal |last=Lake |first=David A. |date=1992-05-01 |title=Neuromuscular Electrical Stimulation |url=https://doi.org/10.2165/00007256-199213050-00003 |journal=Sports Medicine |language=en |volume=13 |issue=5 |pages=320–336 |doi=10.2165/00007256-199213050-00003 |pmid=1565927 |s2cid=9708216 |issn=1179-2035}}</ref> 
* Orthopedic evaluation tools: equipment to evaluate posture, gait and balance disturbances was developed at NASA, along with a radiation-free way to measure bone flexibility using vibration.
* [[Medicine:Diabetes|Diabetic]] foot mapping: This technique was developed at NASA's center in Cleveland, Ohio to help monitor the effects of diabetes in feet.
* Foam cushioning: special foam used for cushioning astronauts during liftoff is used in pillows and mattresses at many nursing homes and hospitals to help prevent ulcers, relieve pressure, and provide a better night's sleep.
* Kidney dialysis machines: the [[Company:Marquardt Corporation|Marquardt Corporation]], an ancestor company with NASA, were developing a system that would purify and recycle water during space missions in the late 1960s.<ref name="ntrs.nasa.gov">{{cite web|url=https://ntrs.nasa.gov/api/citations/20020083273/downloads/20020083273.pdf |title=Critical Care Dialysis System |publisher=NASA|access-date=November 29, 2022}}</ref> From this project, the Marquardt Corporation observed that these processes could be used in removing toxic waste from used dialysis fluid.<ref name="ntrs.nasa.gov"/> This allowed the development of a kidney dialysis machine.<ref name="ntrs.nasa.gov"/> These machines rely on technology developed by NASA in order to process and remove toxic waste from used dialysis fluid.<ref name="ntrs.nasa.gov"/>

[[File:Stephen hawking and lucy hawking nasa 2008 (cropped).jpg|thumb|Dr. Stephen Hawking used the "talking wheelchair" or the Versatile Portable Speech Prosthesis. To operate the VSP, Dr. Hawking used a thumb switch and a blink-switch that was attached to his glasses to control his computer.<ref>{{Cite web|url=https://www.nasa.gov/50th/NASA_lecture_series/hawking.html|title = NASA - NASA's Lecture Series - Prof. Stephen Hawking}}</ref>]]

* Talking [[Engineering:Wheelchair|wheelchair]]s: paralyzed individuals who have difficulty speaking may use a talking feature on their wheelchairs which was developed by NASA to create synthesized speech for aircraft. "Talking Wheelchairs" or The Versatile Portable Speech Prosthesis (VSP) is a technology that aids in the communication for non-verbal persons.<ref name="R e P O R">{{Cite web|url=https://webcache.googleusercontent.com/search?q=cache:gqlP90_YO1sJ:https://ntrs.nasa.gov/api/citations/19820014023/downloads/19820014023.pdf+&cd=11&hl=en&ct=clnk&gl=us&client=firefox-b-1-d|title =Final Report: Research and Developmen of a Versatile Portable Speech Prosthesis|access-date=November 29, 2022}}</ref> The project started in May 1978 and finished in November 1981.<ref name="R e P O R"/> Originally, this technology was created for people who were diagnosed with [[Medicine:Cerebral palsy|cerebral palsy]] who were using traditional electric wheelchairs.<ref name="R e P O R"/> This technology is portable and versatile, as well as a highly successful speech prosthesis.<ref name="R e P O R"/> However, the nickname "talking wheelchair" has created some separation from the wheelchair itself.<ref name="R e P O R"/> The VSP is easily accessible to the person using it by operation of single or multiple switches or by keyboard, and uses a synthetic voice used for verbal speech.<ref name="R e P O R"/> The synthetic voice provides communication opportunities that regular speaking persons have such as: communicating with people in a crowd, communicating in the dark, communicating with people who have vision problems, communicating with younger children, communicating when the listener's back is turned, etc.<ref name="R e P O R"/> The synthetic voice also provides a sense of personal and individual communication as the keyboard can be programmed with “fun” words as well as “throw-away lines”.<ref name="R e P O R"/> The first version of the versatile portable speech prosthesis was completed in May 1979.<ref name="R e P O R"/> There were additions made to the VSP in November 1979 and provided more controls for speech.<ref name="R e P O R"/> By November 1979, VSP was capable of taking English text and successful in putting out English speech.<ref name="R e P O R"/> The user was also able to store and retrieve vocabulary, as well as edit and create new vocabulary.<ref name="R e P O R"/> The controls and plugs on the VSP were versatile allowing plug-and-go ability.<ref name="R e P O R"/> With the limitations of ASR systems, Portable Speech Prosthesis have moved to the use of Silent Speech Recognition (SSR).<ref name="ReferenceA">{{Cite journal|pmc = 6168082|year = 2018|last1 = Meltzner|first1 = G. S.|last2 = Heaton|first2 = J. T.|last3 = Deng|first3 = Y.|last4 = De Luca|first4 = G.|last5 = Roy|first5 = S. H.|last6 = Kline|first6 = J. C.|title = Development of sEMG sensors and algorithms for silent speech recognition|journal = Journal of Neural Engineering|volume = 15|issue = 4|page = 046031|doi = 10.1088/1741-2552/aac965|pmid = 29855428|bibcode = 2018JNEng..15d6031M}}</ref> The goal of using SSR with VSP is to recognize information that is speech related with some modals such as surface electromyography (sEMG).<ref name="ReferenceA"/> Speech recognition models used algorithms for extracting speech-related features through the sEMG signals.<ref name="ReferenceA"/> The patterns of sEMG signals used grammar models to recognize sequences of words.<ref name="ReferenceA"/> Phoneme-based models were also used when recognizing vocabulary of previously untrained words.<ref name="ReferenceA"/> Multi-point sensors were used with these algorithms in which they could be arranged in a flexible way to record the measurements of sEMG signals from the small articular muscles found in the human face and neck.<ref name="ReferenceA"/>
* Collapsible, lightweight wheelchairs: wheelchairs designed for portability that can be folded and put into trunks of cars. They rely on synthetic materials that NASA developed for its air and space craft
* Surgically implantable heart pacemaker: these devices depend on technologies developed by NASA for use with satellites. They communicate information about the activity of the pacemaker, such as how much time remains before the batteries need to be replaced.<ref name=pacemaker>{{cite web| url = https://spinoff.nasa.gov/spinoff1996/25.html| title = Programmable Pacemaker| date = 1996| website = NASA| access-date =September 25, 2022 
| quote =...the NASA-developed technology for two-way communication with satellites that provided a way for physicians to communicate with an implanted pacemaker and reprogram it without surgery.}}</ref>
* Implantable heart [[Medicine:Defibrillator|defibrillator]]: this tool continuously monitors heart activity and can deliver an electric shock to restore heartbeat regularity.
* EMS communications: technology used to communicate telemetry between Earth and space was developed by NASA to monitor the health of astronauts in space from the ground. Ambulances use this same technology to send information—like EKG readings—from patients in transport to hospitals. This allows faster and better treatment.
* [[Physics:Weightlessness|Weightlessness]] therapy: The weightlessness of space can allow some individuals with limited mobility on Earth—even those normally confined to wheelchairs—the freedom to move about with ease. Physicist [[Biography:Stephen Hawking|Stephen Hawking]] took advantage of weightlessness in NASA's Vomit Comet aircraft in 2007.<ref>{{Cite news |url=http://news.bbc.co.uk/2/hi/science/nature/6594821.stm |title=Hawking takes zero-gravity flight |date=2007-04-27 |work=BBC |access-date=2018-02-03 |language=en-GB}}</ref> This idea also led to the development of the Anti-Gravity Treadmill from NASA technology, which employs "differential air pressure to mimic...gravity".<ref name=antigrav>{{cite web| url = https://spinoff.nasa.gov/Spinoff2009/hm_5.html| title = 'Anti-Gravity' Treadmills Speed Rehabilitation| date = 2009| website = NASA| access-date = September 25, 2022}}</ref>

=== Ultrasound microgravity ===

The  [[Medicine:Advanced Diagnostic Ultrasound in Microgravity|Advanced Diagnostic Ultrasound in Microgravity]] Study is funded by the [[Organization:National Space Biomedical Research Institute|National Space Biomedical Research Institute]] and involves the use of ultrasound among Astronauts including former ISS Commanders Leroy Chiao and Gennady Padalka who are guided by remote experts to diagnose and potentially treat hundreds of medical conditions in space. This study has a widespread impact and has been extended to cover professional and Olympic sports injuries as well as medical students. It is anticipated that remote guided ultrasound will have application on Earth in emergency and rural care situations. Findings from this study were submitted for publication to the journal [[Medicine:Radiology|Radiology]] aboard the International Space Station; the first article submitted in space.<ref>{{cite web |url=http://www.nasa.gov/mission_pages/station/science/experiments/ADUM.html |archive-url=https://web.archive.org/web/20070823011200/http://www.nasa.gov/mission_pages/station/science/experiments/ADUM.html |url-status=dead |archive-date=2007-08-23 |title=Advanced Diagnostic Ultrasound in Microgravity (ADUM) |publisher=Nasa.gov |date=2011-11-08 |access-date=2012-02-10}}</ref><ref>{{cite journal |author=Sishir Rao, BA |others= Lodewijk van Holsbeeck, BA, Joseph L. Musial, PhD, Alton Parker, MD, J. Antonio Bouffard, MD, Patrick Bridge, PhD, Matt Jackson, PhD and Scott A. Dulchavsky, MD, PhD |date=May 1, 2008 |title=A Pilot Study of Comprehensive Ultrasound Education at the Wayne State University School of Medicine |journal=Journal of Ultrasound in Medicine |volume=27 |issue=5 |pages=745–749 |pmid=18424650 |doi=10.7863/jum.2008.27.5.745 |doi-access=free }}</ref><ref>{{cite journal |author=E. Michael Fincke, MS |others= Gennady Padalka, MS, Doohi Lee, MD, Marnix van Holsbeeck, MD, Ashot E. Sargsyan, MD, Douglas R. Hamilton, MD, PhD, David Martin, RDMS, Shannon L. Melton, BS, Kellie McFarlin, MD and Scott A. Dulchavsky, MD, PhD |date=February 2005 |title=Evaluation of Shoulder Integrity in Space: First Report of Musculoskeletal US on the International Space Station |journal=Radiology |volume=234 |issue= 2|pages=319–322 |doi=10.1148/radiol.2342041680 |pmid=15533948}}</ref>

== See also ==
{{div col|colwidth=22em}}

* [[Physics:Artificial gravity|Artificial gravity]]
* Aviation medicine
* [[Astronomy:Bioastronautics|Bioastronautics]]
* [[Astronomy:Effect of spaceflight on the human body|Effect of spaceflight on the human body]]
* [[Medicine:Fatigue and sleep loss during spaceflight|Fatigue and sleep loss during spaceflight]]
* [[Medicine:Intervertebral disc damage and spaceflight|Intervertebral disc damage and spaceflight]]
* [[Astronomy:List of microorganisms tested in outer space|List of microorganisms tested in outer space]]
* [[Astronomy:Mars analog habitat|Mars analog habitat]]
* [[Medicine:Medical treatment during spaceflight|Medical treatment during spaceflight]]
* [[Organization:Microgravity University|Microgravity University]]
* [[Astronomy:Reduced-gravity aircraft|Reduced-gravity aircraft]]
* [[Medicine:Renal stone formation in space|Renal stone formation in space]]
* [[Astronomy:Spaceflight osteopenia|Spaceflight osteopenia]]
* [[Medicine:Spaceflight radiation carcinogenesis|Spaceflight radiation carcinogenesis]]
* [[Astronomy:Space food|Space food]]
* [[Medicine:Space nursing|Space nursing]]
* [[Organization:Space Nursing Society|Space Nursing Society]]
* [[Medicine:Space pharmacology|Space pharmacology]]
* [[Astronomy:Team composition and cohesion in spaceflight missions|Team composition and cohesion in spaceflight missions]]
* [[Medicine:Visual impairment due to intracranial pressure|Visual impairment due to intracranial pressure]]
{{div col end}}

== References ==
;Notes
{{reflist|2}}

;Sources
* {{cite journal | author = MacPherson G | year = 2007| title = Altitude Decompression Sickness Susceptibility | journal = Aviation, Space, and Environmental Medicine | volume = 78 | issue = 6| pages = 630–631 | pmid = 17571668}}
* {{cite journal | author1 = John-Baptiste A |author2= Cook T |author3= Straus S |author4= Naglie G | display-authors = etal | year = 2006| title = "Decision Analysis in Aerospace Medicine " Costs and Benefits of a Hyperbaric Facility in Space | journal = Aviation, Space, and Environmental Medicine | volume = 77 | issue = 4| pages = 434–443 | pmid = 16676656 }}
* {{cite journal |author1 = DeGroot D |author2= Devine JA |author3= Fulco CS | title = Incidence of Adverse Reactions from 23,000 Exposures to Simulated Terrestrial Altitudes up to 8900&nbsp;m | journal = Aviation, Space, and Environmental Medicine |year= 2003 | volume = 74 | issue = 9| pages = 994–997 |pmid= 14503681 }}

== External links ==
* [http://spacemedicineassociation.org/sma/ Space Medicine Association]
* [http://iss.sfo.jaxa.jp/med/index_e.html Description of space medicine] {{Webarchive|url=https://web.archive.org/web/20070317024607/http://iss.sfo.jaxa.jp/med/index_e.html |date=2007-03-17 }}
* [https://history.nasa.gov/series95.html NASA History Series Publications] (many of which are online)
* [https://archive.today/20130203203510/http://www.temec.com/portal/node/99 Sleep in Space, Digital Sleep Recorder used by NASA in STS-90 and STS-95 missions]
* [http://www.nasa.gov/mission_pages/station/research/news/IVGEN.html A Solution for Medical Needs and Cramped Quarters in Space – NASA] {{Webarchive|url=https://web.archive.org/web/20160412152906/http://www.nasa.gov/mission_pages/station/research/news/IVGEN.html |date=2016-04-12 }}

{{Space medicine}}
{{Spaceflight}}
{{inspace}}


[[Category:Space medicine| ]]
[[Category:Human spaceflight programs]]

{{Sourceattribution|Space medicine}}