Editing Space exploration (section)

==History of exploration{{anchor|History|History_of_exploration_in_the_20th_century}}==
{{See also|History of astronomy|Discovery and exploration of the Solar System|Timeline of space exploration|Timeline of first orbital launches by country|Outer space#Discovery}}
[[File:Fusée V2.jpg|thumb|[[V-2 Rocket]] in the Peenemünde Museum]]

===First telescopes===
The first [[telescope]] is said to have been invented in 1608 in the [[Netherlands]] by an [[eyeglass]] maker named [[Hans Lippershey]], but their first recorded use in astronomy was by [[Galileo Galilei]] in 1609.<ref>{{cite book |author=King, C. C.|date=2003|title=The History of the Telescope|publisher=Dover Publications|pages=30–32|isbn=978-0-486-43265-6}}</ref> In 1668 [[Isaac Newton]] built [[Newton's reflector|his own]] [[reflecting telescope]], the first fully functional telescope of this kind, and a landmark for future developments due to its superior features over the previous [[Refracting telescope#Galilean telescope|Galilean telescope]].<ref name="books.google.com">{{cite book|author=A. Rupert Hall|title=Isaac Newton: Adventurer in Thought|url=https://archive.org/details/isaacnewtonadven0000hall|url-access=registration|year=1996|publisher=Cambridge University Press|isbn=978-0-521-56669-8|page=[https://archive.org/details/isaacnewtonadven0000hall/page/67 67]}}</ref>

A string of [[Timeline of discovery of Solar System planets and their moons|discoveries in the Solar System]] (and beyond) followed, then and in the [[Scientific Revolution|next centuries]]: the [[Lunar craters|mountains of the Moon]], the [[phases of Venus]], [[Galilean Moons|the main satellites]] of [[satellites of Jupiter|Jupiter]] and [[Satellites of Saturn|Saturn]], the [[Saturn's rings|rings of Saturn]], many [[comet]]s, the [[asteroid]]s, the new planets [[Uranus]] and [[Neptune]], and many more [[List of natural satellites|satellites]].

The [[Orbiting Astronomical Observatory 2]] was the first [[space telescope]] launched 1968,<ref name=joseph>{{cite book|first=Joseph A.|last=Angelo|title=Spacecraft for Astronomy |url= https://books.google.com/books?id=y8BMepjeciEC&pg=PA20|year=2014|publisher=Infobase Publishing|isbn=978-1-4381-0896-4|page=20}}</ref> but the launching of [[Hubble Space Telescope]] in 1990<ref>{{cite web |url=http://science.ksc.nasa.gov/shuttle/missions/sts-31/mission-sts-31.html |title=STS-31 |publisher=NASA |access-date=April 26, 2008 |archive-date= August 15, 2011 |archive-url= https://web.archive.org/web/20110815191242/http://science.ksc.nasa.gov/shuttle/missions/sts-31/mission-sts-31.html |url-status=live }}</ref> set a milestone. As of 1 December 2022, there were 5,284 confirmed [[Lists of exoplanets|exoplanets]] discovered. The [[Milky Way]] is estimated to contain 100–400 billion [[star]]s<ref>{{cite web |url= http://asd.gsfc.nasa.gov/blueshift/index.php/2015/07/22/how-many-stars-in-the-milky-way/ |title=How Many Stars in the Milky Way? |work=NASA Blueshift |url-status=live |archive-url= https://web.archive.org/web/20160125140109/http://asd.gsfc.nasa.gov/blueshift/index.php/2015/07/22/how-many-stars-in-the-milky-way/ |archive-date=25 January 2016 }}</ref> and more than 100 billion [[planets]].<ref name="Space-20130102">{{cite news |author=|title=100 Billion Alien Planets Fill Our Milky Way Galaxy: Study |url=http://www.space.com/19103-milky-way-100-billion-planets.html |date=2 January 2013 |work=[[Space.com]] |access-date= |archive-url=https://web.archive.org/web/20130103060601/http://www.space.com/19103-milky-way-100-billion-planets.html |archive-date=3 January 2013 |url-status=live}}</ref> There are at least 2 trillion [[galaxy|galaxies]] in the [[observable universe]].<ref name="Conselice">{{cite journal |title= The Evolution of Galaxy Number Density at ''z'' < 8 and Its Implications |first=Christopher J. |last=Conselice |display-authors=etal |journal=The Astrophysical Journal |volume= 830 |issue=2 |year=2016 |arxiv=1607.03909v2 |bibcode= 2016ApJ...830...83C |doi=10.3847/0004-637X/830/2/83 |page=83|s2cid=17424588 |doi-access=free }}</ref><ref name="NYT-20161017">{{cite news |last=Fountain |first=Henry |title=Two Trillion Galaxies, at the Very Least |url=https://www.nytimes.com/2016/10/18/science/two-trillion-galaxies-at-the-very-least.html |date=17 October 2016 |work=[[The New York Times]]|access-date=17 October 2016 }}</ref> [[HD1]] is the [[List of the most distant astronomical objects|most distant]] known object from Earth, reported as 33.4 billion [[light-year]]s away.<ref name="ALMA-20220407">{{cite news |last1=Lira |first1=Nicolás |last2=Iono |first2=Daisuke |last3=Oliver |first3=Amy C. |last4=Ferreira |first4=Bárbara |date=7 April 2022 |title=Astronomers Detect Most Distant Galaxy Candidate Yet |url=https://www.almaobservatory.org/en/press-releases/astronomers-detect-most-distant-galaxy-candidate-yet/ |url-status=dead |archive-url=https://web.archive.org/web/20220717040741/https://www.almaobservatory.org/en/press-releases/astronomers-detect-most-distant-galaxy-candidate-yet/ |archive-date=17 July 2022 |accessdate=8 April 2022 |work=[[Atacama Large Millimeter Array]]}}</ref><ref name="ARX-20220212">{{cite journal |author=Harikane, Yuichi |display-authors=et al. |title=A Search for H-Dropout Lyman Break Galaxies at z ∼ 12–16 |journal=The Astrophysical Journal |arxiv=2112.09141 |date=2 February 2022 |volume=929 |issue= 1 |page=1 |doi=10.3847/1538-4357/ac53a9 |bibcode=2022ApJ...929....1H |s2cid=246823511 |doi-access=free }}</ref><ref name="NS-20220407">{{cite news |last=Crane |first=Leah |title= Astronomers have found what may be the most distant galaxy ever seen – A galaxy called HD1 appears to be about 33.4 billion light years away, making it the most distant object ever seen – and its extreme brightness is puzzling researchers |url=https://www.newscientist.com/article/2315330-astronomers-have-found-what-may-be-the-most-distant-galaxy-ever-seen/ |date=7 April 2022 |work=[[New Scientist]] |accessdate=8 April 2022 }}</ref><ref name="MN-20220407">{{cite journal |author=Pacucci, Fabio |display-authors=et al. |title=Are the newly-discovered z ∼ 13 drop-out sources starburst galaxies or quasars? |date=7 April 2022 |journal=[[Monthly Notices of the Royal Astronomical Society]] |volume=514 |pages=L6–L10 |doi=10.1093/mnrasl/slac035 |doi-access=free |arxiv=2201.00823 }}</ref><ref name="AST-20220407">{{cite news |last=Buongiorno |first=Caitlyn |title=Astronomers discover the most distant galaxy yet - Unusually bright in ultraviolet light, HD1 may also set another cosmic record. |url=https://astronomy.com/news/2022/04/researchers-discover-the-most-distant-galaxy-yet |date=7 April 2022 |work=[[Astronomy (magazine)|Astronomy]] |accessdate=7 April 2022 }}</ref><ref name="INV-20220407">{{cite news |last=Wenz |first=John |title=Behold! Astronomers May Have Discovered The Most Distant Galaxy Ever – HD1 could be from just 300 million years after the Big Bang. |url=https://www.inverse.com/science/most-distant-galaxy-discovery |date=7 April 2022 |work=[[Inverse (website)|Inverse]] |accessdate=7 April 2022 }}</ref>

===First outer space flights===
[[File:Vostok spacecraft.jpg|thumb|Model of Vostok spacecraft]]
[[File:Apollo CSM lunar orbit.jpg|thumb|Apollo Command Service Module in lunar orbit]]

[[MW 18014]] was a German [[V-2 rocket]] test launch that took place on 20 June 1944, at the [[Peenemünde Army Research Center]] in [[Peenemünde]]. It was the first human-made object to reach [[outer space]], attaining an [[apogee]] of 176 kilometers,<ref name="psv">{{cite journal |author=Milazzo |first1=M. P. |last2=Kestay |first2=L. |last3=Dundas |first3=C. |author4=U.S. Geological Survey |year=2017 |title=The Challenge for 2050: Cohesive Analysis of More Than One Hundred Years of Planetary Data |url=https://www.hou.usra.edu/meetings/V2050/pdf/8070.pdf |journal=Planetary Science Vision 2050 Workshop |publisher=Planetary Science Division, NASA |volume=1989 |pages=8070 |bibcode=2017LPICo1989.8070M |accessdate=2019-06-07}}</ref> which is well above the [[Kármán line]].<ref name="Karman line">{{cite web | url=http://www.universetoday.com/25410/how-far-is-space/ | title=How high is space? | website=[[Universe Today]] | last=Williams | first=Matt | date=2016-09-16 | accessdate=2017-05-14 | url-status=live | archiveurl=https://web.archive.org/web/20170602105939/https://www.universetoday.com/25410/how-far-is-space/ | archivedate=2017-06-02 }}</ref> It was a vertical test launch. Although the rocket reached space, it did not reach [[orbital speed|orbital velocity]], and therefore returned to Earth in an impact, becoming the first [[sub-orbital spaceflight]].<ref>{{cite web |title=V-2 rocket (MW 18014) became the first human-made object in space on June 20, 1944 |url=https://ourplnt.com/v-2-rocket-mw-18014-first-human-made-object-in-space/ |website=Our Planet |date=20 June 2022 |access-date=11 July 2022}}</ref> In 1949, the [[Bumper-WAC]] reached an altitude of {{convert|393|km||||}}, becoming the first human-made object to enter space, according to [[NASA]].<ref>{{cite web|url=https://www.nasa.gov/mission_pages/explorer/bumper.html|title=First Human-Made Object to Enter Space|work=NASA|date=3 January 2008}}</ref>

===First object in orbit===
The first successful orbital launch was of the [[Soviet Union|Soviet]] uncrewed ''[[Sputnik 1]]'' ("Satellite 1") mission on 4 October 1957. The satellite weighed about {{convert|83|kg|lb|abbr=on}}, and is believed to have orbited Earth at a height of about {{convert|250|km|mi|abbr=on}}. It had two radio transmitters (20 and 40&nbsp;MHz), which emitted "beeps" that could be heard by radios around the globe. Analysis of the radio signals was used to gather information about the electron density of the ionosphere, while temperature and pressure data was encoded in the duration of radio beeps. The results indicated that the satellite was not punctured by a [[meteoroid]]. ''Sputnik 1'' was launched by an [[R-7 Semyorka|R-7]] rocket. It burned up upon re-entry on 3 January 1958.

===First human outer space flight===
The first successful human spaceflight was ''[[Vostok 1]]'' ("East 1"), carrying the 27-year-old Russian [[cosmonaut]], [[Yuri Gagarin]], on 12 April 1961. The spacecraft completed one orbit around the globe, lasting about 1 hour and 48 minutes. Gagarin's flight resonated around the world; it was a demonstration of the advanced [[Soviet space program]] and it opened an entirely new era in space exploration: [[human spaceflight]].

=== First astronomical body space explorations ===
The first artificial object to reach another celestial body was [[Luna 2]] reaching the [[Moon]] in 1959.<ref name="jpl-luna2">{{cite web|url=http://sse.jpl.nasa.gov/missions/profile.cfm?Sort=Target&Target=Moon&MCode=Luna_02 |title=NASA on Luna 2 mission |publisher=Sse.jpl.nasa.gov |access-date=24 May 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120331155310/http://sse.jpl.nasa.gov/missions/profile.cfm?Sort=Target&Target=Moon&MCode=Luna_02 |archive-date=31 March 2012 }}</ref> The first [[Soft landing (aeronautics)|soft landing]] on another celestial body was performed by [[Luna 9]] landing on the Moon on 3 February 1966.<ref name="jpl.luna9">{{cite web|url=http://sse.jpl.nasa.gov/missions/profile.cfm?Sort=Target&Target=Moon&MCode=Luna_09 |title=NASA on Luna 9 mission |publisher=Sse.jpl.nasa.gov |access-date=24 May 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120331155324/http://sse.jpl.nasa.gov/missions/profile.cfm?Sort=Target&Target=Moon&MCode=Luna_09 |archive-date=31 March 2012 }}</ref> [[Luna 10]] became the first artificial satellite of the Moon, entering in a lunar orbit on 3 April 1966.<ref name="jpl-luna10">{{cite web|url=http://sse.jpl.nasa.gov/missions/profile.cfm?Sort=Target&Target=Moon&MCode=Luna_10 |title=NASA on Luna 10 mission |publisher=Sse.jpl.nasa.gov |access-date=24 May 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120218232128/http://sse.jpl.nasa.gov/missions/profile.cfm?Sort=Target&Target=Moon&MCode=Luna_10 |archive-date=18 February 2012 }}</ref>

The first crewed landing on another celestial body was performed by [[Apollo 11]] on 20 July 1969, landing on the Moon. There have been a total of six spacecraft with humans [[Moon landing|landing on the Moon]] starting from 1969 to the last human landing in 1972.

The first interplanetary [[Flyby (spaceflight)|flyby]] was the 1961 [[Venera 1]] flyby of [[Venus]], though the 1962 [[Mariner 2]] was the first flyby of [[Venus]] to return data (closest approach 34,773 kilometers). [[Pioneer 6, 7, 8, and 9|Pioneer 6]] was the first satellite to orbit the [[Sun]], launched on 16 December 1965. The other planets were first flown by in 1965 for [[Mars]] by [[Mariner 4]], 1973 for [[Jupiter]] by ''[[Pioneer 10]]'', 1974 for [[Mercury (planet)|Mercury]] by [[Mariner 10]], 1979 for [[Saturn]] by ''[[Pioneer 11]]'', 1986 for [[Uranus]] by ''[[Voyager 2]]'', 1989 for [[Neptune]] by ''[[Voyager 2]]''. In 2015, the [[dwarf planet]]s [[Ceres (dwarf planet)|Ceres]] and [[Pluto]] were orbited by ''[[Dawn (spacecraft)|Dawn]]'' and passed by ''[[New Horizons]]'', respectively. This accounts for flybys of each of the eight planets in the [[Solar System]], the [[Sun]], the [[Moon]], and [[Ceres (dwarf planet)|Ceres]] and [[Pluto]] (two of the five [[Dwarf_planet#Population_of_dwarf_planets|recognized dwarf planets]]).

The first interplanetary surface mission to return at least limited surface data from another planet was the 1970 landing of [[Venera 7]], which returned data to Earth for 23 minutes from [[Venus]]. In 1975, [[Venera 9]] was the first to return images from the surface of another planet, returning images from Venus. In 1971, the [[Mars 3]] mission achieved the first soft landing on Mars returning data for almost 20 seconds. Later, much longer duration surface missions were achieved, including over six years of Mars surface operation by [[Viking 1]] from 1975 to 1982 and over two hours of transmission from the surface of Venus by [[Venera 13]] in 1982, the longest ever Soviet planetary surface mission. Venus and Mars are the two planets outside of Earth on which humans have conducted surface missions with uncrewed [[robotic spacecraft]].

=== First space station ===
[[Salyut 1]] was the first [[space station]] of any kind, launched into [[low Earth orbit]] by the [[Soviet Union]] on 19 April 1971. The [[International Space Station]] (ISS) is currently the largest and oldest of the 2 current fully functional space stations, inhabited continuously since the year 2000. The other, Tiangong space station built by China, is now fully crewed and operational.

===First interstellar space flight===
''[[Voyager 1]]'' became the first human-made object to [[List of artificial objects leaving the Solar System|leave the Solar System]] into [[Outer space#Interstellar space|interstellar space]] on 25 August 2012. The probe passed the [[Heliopause (astronomy)|heliopause]] at 121 [[Astronomical unit|AU]] to enter [[Interstellar medium|interstellar space]].<ref>{{cite news |title=Voyager 1 finally crosses into interstellar space |first=William |last=Harwood |work=[[CBS News]] |date=12 September 2013 |url=https://www.cbsnews.com/news/voyager-1-finally-crosses-into-interstellar-space/ |access-date=1 February 2019 |archive-date=13 November 2013 |archive-url=https://web.archive.org/web/20131113201639/http://www.cbsnews.com/8301-205_162-57602736/voyager-1-finally-crosses-into-interstellar-space/ |url-status=live }}</ref>

===Farthest from Earth===
The [[Apollo 13]] flight passed the [[far side of the Moon]] at an altitude of {{convert|254|km|mi nmi|sp=us|abbr=off}} above the lunar surface, and 400,171&nbsp;km (248,655&nbsp;mi) from Earth, marking the [[List of spaceflight records|record]] for the farthest humans have ever traveled from Earth in 1970.

{{As of|2025|02|09}} ''[[Voyager 1]]'' was at a distance of {{convert|166.4|AU|e9km e9mi|abbr=unit}} from Earth.<ref name="voyager">{{cite web | url=https://voyager.jpl.nasa.gov/mission/status/ | title=Voyager – Mission Status | work=[[Jet Propulsion Laboratory]] | publisher=[[National Aeronautics and Space Administration]] | access-date=1 January 2019}}</ref> It is the most distant human-made object from Earth.<ref>{{cite web |url=http://www.bbc.co.uk/science/space/solarsystem/space_missions/voyager_1 |title=Voyager 1 |work=[[BBC]] Solar System |access-date=4 September 2018 |archive-url=https://web.archive.org/web/20180203195855/http://www.bbc.co.uk/science/space/solarsystem/space_missions/voyager_1 |archive-date=3 February 2018 |url-status=dead |df=mdy-all }}</ref>