Editing Space suit (section)

===Physiological effects of unprotected space exposure===
{{Main|Space exposure}}
The human body can briefly survive the hard vacuum of space unprotected,<ref name="Bellows2006">{{cite web |url=http://www.damninteresting.com/outer-space-exposure |title=Outer Space Exposure |last=Bellows |first=Alan |date=November 27, 2006 |website=Damn Interesting |id=Article #237 |access-date=June 19, 2013}}</ref> despite contrary depictions in some popular [[science fiction]]. Consciousness is retained for up to 15 seconds as the effects of [[Hypoxia (medical)|oxygen starvation]] set in. No snap freeze effect occurs because all heat must be lost through [[thermal radiation]] or the [[evaporation]] of liquids, and the blood does not boil because it remains pressurized within the body, but human flesh expands up to about twice its volume due to [[ebullism]] in such conditions, giving the visual effect of a body builder rather than an overfilled balloon.<ref name="Springel 2013" >{{cite web|date=30 July 2013 |first=Mark|last=Springel |publisher=Harvard University Graduate School of Arts and Sciences |url=https://sitn.hms.harvard.edu/flash/2013/space-human-body/ |title=The human body in space: Distinguishing fact from fiction |access-date=6 October 2023}}</ref>

In space, there are highly energized [[subatomic particle]]s that can cause [[radiation damage]] by disrupting essential biological processes. Exposure to radiation can create problems via two methods: the particles can react with water in the human body to produce [[free radicals]] that break DNA molecules apart, or by directly breaking the DNA molecules.<ref name=thomas>{{cite book|last1=Thomas|first1=Kenneth S.|last2=McMann|first2=Harold J.|title=U.S. Spacesuits|date=23 November 2011|publisher=Springer Science & Business Media |isbn=978-1-4419-9566-7 }}</ref><ref>{{cite web|title=Space Radiation Analysis Group|url=http://srag.jsc.nasa.gov/Index.cfm|website=NASA, Johnson Space Center|publisher=NASA|access-date=16 February 2015|archive-url=https://web.archive.org/web/20150218045538/http://srag.jsc.nasa.gov/Index.cfm|archive-date=February 18, 2015}}</ref>

Temperature in space can vary extremely depending on the exposure to radiant energy sources. Temperatures from solar radiation can reach up to {{convert|250|°F}}, and in its absence, down to {{convert|-387|°F|0}}. Because of this, space suits must provide sufficient insulation and cooling for the conditions in which they will be used.<ref name=thomas/>

The vacuum environment of space has no pressure, so gases will expand and exposed liquids may evaporate. Some solids may [[Sublimation (phase transition)|sublimate]]. It is necessary to wear a suit that provides sufficient internal body pressure in space.<ref name=thomas/><ref>{{cite book|last1=Hanslmeier|first1=Arnold|title=The Sun and Space Weather|date=1 January 2002|publisher=Springer Science & Business Media|isbn=1-4020-0684-5|pages=166–67|edition=Illustrated}}</ref> The most immediate hazard is in attempting to hold one's breath during [[Uncontrolled decompression#Explosive decompression|explosive decompression]] as the expansion of gas can damage the lungs by overexpansion rupture. These effects have been confirmed through various accidents (including in very-high-altitude conditions, outer space and training [[vacuum chamber]]s).<ref name="Bellows2006" /><ref>{{cite web |url=http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html |title=Ask an Astrophysicist: Human Body in a Vacuum |website=Image the Universe! |publisher=[[NASA]] |access-date=December 14, 2008}}</ref> Human skin does not need to be protected from vacuum and is gas-tight by itself.<ref name="Springel 2013" /> It only needs to be mechanically restrained to retain its normal shape and the internal tissues to retain their volume. This can be accomplished with a tight-fitting elastic body suit and a [[helmet]] for containing [[breathing gas]]es, known as a [[space activity suit]] (SAS).{{clarify|how does this affect breathing?|date=September 2023 }}{{citation needed|date=October 2023}}<!-- uncontroversial but I can't remember the sources right now. It is probably in Thomas, but I don't have access-->