Editing Spaceflight (section)

== Challenges ==
{{main|Human spaceflight|Effect of spaceflight on the human body}}

=== Safety ===
{{Main|List of spaceflight-related accidents and incidents}}

All launch vehicles contain a huge amount of energy that is needed for some part of it to reach orbit. There is therefore some risk that this energy can be released prematurely and suddenly, with significant effects. When a [[Delta II]] rocket exploded 13 seconds after launch on January 17, 1997, there were reports of store windows {{convert|10|mi|km}} away being broken by the blast.<ref>{{cite news | url = http://www.cnn.com/TECH/9701/17/rocket.explosion/index.html | title = Unmanned rocket explodes after liftoff | publisher = CNN }}</ref>

Space is a fairly predictable environment, but there are still risks of accidental depressurization and the potential failure of equipment, some of which may be very newly developed.

In April 2004 the [[International Association for the Advancement of Space Safety]] was established in the [[Netherlands]] to further international cooperation and scientific advancement in space systems safety.<ref>{{cite web |url=http://www.congrex.nl/07a02/ |archive-url=https://archive.today/20120724193521/http://www.congrex.nl/07a02/ |url-status=dead |archive-date=24 July 2012 |title= The second IAASS: Introduction |access-date=3 January 2009 |work=Congrex |publisher=European Space Agency}}</ref>

=== Weightlessness ===
{{Main|Weightlessness}}
[[Image:Foale ZeroG.jpg|thumb|upright=1.1|Astronauts on the [[International Space Station|ISS]] in weightless conditions. [[Michael Foale]] can be seen exercising in the foreground.]]

In a microgravity environment such as that provided by a spacecraft in orbit around the Earth, humans experience a sense of "weightlessness." Short-term exposure to microgravity causes [[space adaptation syndrome]], a self-limiting nausea caused by derangement of the [[vestibular system]]. Long-term exposure causes multiple health issues. The most significant is bone loss, some of which is permanent, but microgravity also leads to significant [[deconditioning]] of muscular and cardiovascular tissues.

=== Radiation ===
Once above the atmosphere, radiation due to the [[Van Allen belts]], [[solar radiation]] and [[cosmic radiation]] issues occur and increase. Further away from the Earth, [[solar flare]]s can give a fatal radiation dose in minutes, and the [[Health threat from cosmic rays|health threat from cosmic radiation]] significantly increases the chances of cancer over a decade exposure or more.<ref>[https://science.nasa.gov/science-news/science-at-nasa/2002/16sep_rightstuff/ Super Spaceships] {{Webarchive|url=https://web.archive.org/web/20190713161328/https://science.nasa.gov/science-news/science-at-nasa/2002/16sep_rightstuff/ |date=2019-07-13 }}, ''[[NASA]]'', 16 September 2002, Retrieved 25 October 2011.</ref>

=== Life support ===
{{Main|Life support system}}

In human spaceflight, the [[life support system]] is a group of devices that allow a human being to survive in outer space. [[NASA]] often uses the phrase Environmental Control and Life Support System or the acronym ECLSS when describing these systems for its [[human spaceflight]] missions.<ref>{{cite web|url=https://science.nasa.gov/headlines/y2000/ast13nov_1.htm |title=Breathing Easy on the Space Station |publisher=NASA |url-status=dead |archive-url=https://web.archive.org/web/20080921141609/https://science.nasa.gov/headlines/y2000/ast13nov_1.htm |archive-date=2008-09-21 }}</ref> The life support system may supply: [[air]], [[water]] and [[food]]. It must also maintain the correct body temperature, an acceptable pressure on the body and deal with the body's waste products. Shielding against harmful external influences such as radiation and micro-meteorites may also be necessary. Components of the life support system are [[Life-critical system|life-critical]], and are designed and constructed using [[safety engineering]] techniques.

=== Space weather ===
{{Main|Space weather}}
[[Image:Aurora-SpaceShuttle-EO.jpg|thumb|upright=1.1|[[Aurora (astronomy)|Aurora australis]] and [[Space Shuttle Discovery|''Discovery'']], May 1991]]

Space weather is the concept of changing environmental conditions in [[outer space]]. It is distinct from the concept of [[weather]] within a [[Celestial body atmosphere|planetary atmosphere]], and deals with phenomena involving ambient [[Plasma (physics)|plasma]], magnetic fields, [[radiation]] and other [[matter]] in space (generally close to Earth but also in [[interplanetary space|interplanetary]], and occasionally [[interstellar medium]]). "Space weather describes the conditions in space that affect Earth and its technological systems. Our space weather is a consequence of the behavior of the Sun, the nature of Earth's magnetic field, and our location in the Solar System."<ref>[http://www7.nationalacademies.org/ssb/SSB_Space_weather97.pdf Space Weather: A Research Perspective] {{Webarchive|url=https://web.archive.org/web/20090326235324/http://www7.nationalacademies.org/ssb/SSB_Space_weather97.pdf |date=2009-03-26 }}, [[National Academy of Sciences]], 1997</ref>

Space weather exerts a profound influence in several areas related to space exploration and development. Changing geomagnetic conditions can induce changes in atmospheric density causing the rapid degradation of spacecraft altitude in [[Low Earth orbit]]. Geomagnetic storms due to increased solar activity can potentially blind sensors onboard spacecraft, or interfere with on-board electronics. An understanding of space environmental conditions is also important in designing shielding and life support systems for crewed spacecraft.

=== Environmental considerations ===
{{Main|Space sustainability|Space debris|Graveyard orbit|Spacecraft cemetery}}
Exhaust pollution of rockets depends on the produced exhausts by the propellants reactions and the location of exhaustion. They mostly exhaust [[greenhouse gas]]es and sometimes toxic components. Particularly at higher levels of the atmosphere the potency of exhausted gases as greenhouse gases increases considerably.<ref name="Gammon 2021"/> Many solid rockets have chlorine in the form of [[perchlorate]] or other chemicals, and this can cause temporary local holes in the ozone layer. Re-entering spacecraft generate nitrates which also can temporarily impact the ozone layer. Most rockets are made of metals that can have an environmental impact during their construction.
While spaceflight altogether pollutes at a fraction of other human activities, it still does pollute heavily if calculated per passenger.<ref name="Gammon 2021">{{cite web | last=Gammon | first=Katharine | title=How the billionaire space race could be one giant leap for pollution | website=the Guardian | date=2021-07-19 | url=http://www.theguardian.com/science/2021/jul/19/billionaires-space-tourism-environment-emissions | access-date=2022-05-05}}</ref>

In addition to the atmospheric effects there are effects on the near-Earth space environment. There is the possibility that orbit could become inaccessible for generations due to exponentially increasing [[space debris]] caused by [[spalling]] of satellites and vehicles ([[Kessler syndrome]]). Many launched vehicles today are therefore designed to be re-entered after use.

=== Regulation ===
{{Main|Space law}}

A wide range of issues such as [[space traffic management]] or [[Liability Convention|liability]] have been issues of spaceflight regulation.

Participation and representation of all humanity in spaceflight is an issue of international [[space law]] ever since the first phase of space exploration.<ref name="Durrani"/> Even though some rights of non-spacefaring countries have been secured, sharing of space for all humanity is still criticized as [[imperialism|imperialist]] and lacking, understanding spaceflight as a resource.<ref name="Durrani">{{cite magazine |url=https://www.thenation.com/article/archive/apollo-space-lunar-rockets-colonialism/ |title=Is Spaceflight Colonialism? |author=Haris Durrani |access-date=2 October 2020 |date=19 July 2019|magazine=The Nation}}</ref>

=== Access ===
Inclusion has been a national and international issue, resulting in 1967 in the [[Outer Space Treaty]] and its claim of outer space as the "[[Common heritage of mankind|province of all mankind]]". Furthermore social inclusion in human spaceflight has been demanded, with [[Women in space|women to fly to space]] being limited, and minorities, like people with disability, only having been selected in [[European Space Agency]]'s [[2022 European Space Agency Astronaut Group|2022 astronaut group]].

The dominating issue about access in most recent years has been the issue of [[space debris]] and [[space sustainability]], since established spacefaring countries endanger access to outer space with their orbital space polluting activity.<ref name="v399">{{cite journal | last1=Yap | first1=Xiao-Shan | last2=Heiberg | first2=Jonas | last3=Truffer | first3=Bernhard | title=The emerging global socio-technical regime for tackling space debris: A discourse network analysis | journal=Acta Astronautica | volume=207 | date=2023 | doi=10.1016/j.actaastro.2023.01.016 | pages=445–454| bibcode=2023AcAau.207..445Y }}</ref>