Editing Outer space (section)

==Application==
{{See also|Space science|Benefits of space exploration|Earth observation|Commercialization of space|Space habitation}}
[[File:ISS-44 Milky Way.jpg|thumb|300px|The [[International Space Station]] is an orbiting laboratory for space applications and habitability. Visible in the background is the yellow-green [[airglow]] of Earth's [[ionosphere]] and the interstellar field of the Milky Way.]]
Outer space has become an important element of global society. It provides multiple applications that are beneficial to the economy and scientific research.

The placing of artificial satellites in Earth orbit has produced numerous benefits and has become the dominating sector of the [[space economy]]. They allow relay of [[Communications satellite|long-range communications]] like television, provide a means of [[Satellite navigation|precise navigation]], and permit direct monitoring of [[Weather satellite|weather conditions]] and [[remote sensing]] of the Earth. The latter role serves a variety of purposes, including tracking soil moisture for agriculture, prediction of water outflow from seasonal snow packs, detection of diseases in plants and trees, and [[Spy satellite|surveillance]] of military activities.{{sfn|Razani|2012|pp=97–99}} They facilitate the discovery and monitoring of [[climate change]] influences.<ref name="Space Foundation 2023 k582"/> Satellites make use of the significantly reduced drag in space to stay in stable orbits, allowing them to efficiently span the whole globe, compared to for example [[stratospheric balloon]]s or [[high-altitude platform station]]s, which have other benefits.<ref name="Bisset 2023 s159"/>

The absence of air makes outer space an ideal location for astronomy at all wavelengths of the [[electromagnetic spectrum]]. This is evidenced by the pictures sent back by the Hubble Space Telescope, allowing light from more than 13&nbsp;billion years ago—almost to the time of the Big Bang—to be observed.<ref name=hubblesite_cosmicdawn /> Not every location in space is ideal for a telescope. The [[Interplanetary dust cloud|interplanetary zodiacal dust]] emits a diffuse near-infrared radiation that can mask the emission of faint sources such as extrasolar planets. Moving an [[infrared telescope]] out past the dust increases its effectiveness.<ref name=esa105/> Likewise, a site like the [[Daedalus (crater)|Daedalus crater]] on the [[far side of the Moon]] could shield a [[radio telescope]] from the [[Electromagnetic interference|radio frequency interference]] that hampers Earth-based observations.<ref name=maccone2001/>

[[File:Solardisk.jpg|right|thumb|Concept for a [[space-based solar power]] system to beam energy down to Earth<ref name=BBC_2020/>]]
The deep vacuum of space could make it an attractive environment for certain industrial processes, such as those requiring ultraclean surfaces.<ref name=chapman1991/> Like [[asteroid mining]], [[space manufacturing]] would require a large financial investment with little prospect of immediate return.<ref name="IJA10_307"/> An important factor in the total expense is the high cost of placing mass into Earth orbit: ${{Inflation|US|6000|2006|r=-3|fmt=c}}–${{Inflation|US|20000|2006|r=-3|fmt=c}} per kg, according to a 2006 estimate (allowing for inflation since then).<ref name="jsr43_3_696"/> The cost of access to space has declined since 2013. Partially reusable rockets such as the [[Falcon 9]] have lowered access to space below 3500 dollars per kilogram. With these new rockets the cost to send materials into space remains prohibitively high for many industries. Proposed concepts for addressing this issue include, fully [[reusable launch system]]s, [[non-rocket spacelaunch]], [[momentum exchange tether]]s, and [[space elevators]].{{sfn|Bolonkin|2010|p=xv}}

[[Interstellar travel]] for a human crew remains at present only a theoretical possibility. The distances to the nearest stars mean it would require new technological developments and the ability to safely sustain crews for journeys lasting several decades. For example, the [[Project Daedalus|Daedalus Project]] study, which proposed a spacecraft powered by the [[nuclear fusion|fusion]] of [[deuterium]] and [[helium-3]], would require 36 years to reach the "nearby" [[Alpha Centauri]] system. Other proposed interstellar propulsion systems include [[light sail]]s, [[Bussard ramjet|ramjets]], and [[beam-powered propulsion]]. More advanced propulsion systems could use [[antimatter]] as a fuel, potentially reaching [[relativistic speed|relativistic velocities]].<ref name=Crawford1990/>

From the Earth's surface, the ultracold temperature of outer space can be used as a [[Renewable energy|renewable]] cooling technology for various applications on Earth through [[passive daytime radiative cooling]].<ref name=Yu_et_al_2022/><ref name=Ma_2021/> This enhances [[Long-wave infrared|longwave infrared]] (LWIR) [[thermal radiation]] heat transfer through the atmosphere's [[infrared window]] into outer space, lowering ambient temperatures.<ref name="Zevenhovena-2018"/><ref name="Wang-2021"/> [[Photonic metamaterial]]s can be used to suppress solar heating.<ref name="Heo-2022"/>