Editing Near-Earth object (section)

== Exploratory missions ==
{{Further|List of minor planets and comets visited by spacecraft}}

Some NEOs are of special interest because the [[Delta-v budget|sum total of changes in orbital speed]] required to send a spacecraft on a mission to physically explore an NEO – and thus the amount of rocket fuel required for the mission – is lower than what is necessary for even lunar missions, due to their combination of low velocity with respect to Earth and weak gravity. They may present interesting scientific opportunities both for direct geochemical and astronomical investigation, and as potentially economical sources of extraterrestrial materials for human exploitation.<ref name="USAToday-NEA">{{cite news |first=Dan |last=Vergano |title=Near-Earth asteroids could be 'steppingstones to Mars' |date=February 2, 2007 |work=[[USA Today]] |url=https://www.usatoday.com/tech/science/space/2007-02-12-asteroid_x.htm |access-date=November 18, 2017 |url-status=dead |archive-url=https://web.archive.org/web/20120417034648/http://www.usatoday.com/tech/science/space/2007-02-12-asteroid_x.htm |archive-date=April 17, 2012}}</ref> This makes them an attractive target for exploration.<ref>{{cite journal |title=Design and optimization of trajectory to Near-Earth asteroid for sample return mission using gravity assists |first1=Rui |last1=Xu |first2=Pingyuan |last2=Cui |first3=Dong |last3=Qiao |first4=Enjie |last4=Luan |name-list-style=amp |journal=Advances in Space Research |volume=40 |issue=2 |pages=200–225 |date=March 18, 2007 |doi=10.1016/j.asr.2007.03.025 |bibcode=2007AdSpR..40..220X}}</ref>

=== Missions to NEAs ===
[[File:PIA02475 Eros' Bland Butterscotch Colors.jpg|thumb|Different views of [[433 Eros]] as seen by NASA's ''[[NEAR Shoemaker]]'' probe]]
[[File:Bennu mosaic OSIRIS-REx (square).png|thumb|Image mosaic of asteroid [[101955 Bennu]], target of NASA's ''[[OSIRIS-REx]]'' probe]]

The IAU held a minor planets workshop in [[Tucson, Arizona]], in March 1971. At that point, launching a spacecraft to asteroids was considered premature; the workshop only inspired the first astronomical survey specifically aiming for NEAs.<ref name="wired20130323"/> Missions to asteroids were considered again during a workshop at the [[University of Chicago]] held by NASA's Office of Space Science in January 1978. Of all of the near-Earth asteroids (NEA) that had been discovered by mid-1977, it was estimated that spacecraft could [[Space rendezvous|rendezvous]] with and return from only about 1 in 10 using less [[Spacecraft propulsion|propulsive energy]] than is necessary to reach [[Mars]]. It was recognised that due to the low surface gravity of all NEAs, moving around on the surface of an NEA would cost very little energy, and thus space probes could gather multiple samples.<ref name="wired20130323"/> Overall, it was estimated that about one percent of all NEAs might provide opportunities for [[human spaceflight|human-crewed]] missions, or no more than about ten NEAs known at the time. A five-fold increase in the NEA discovery rate was deemed necessary to make a crewed mission within ten years worthwhile.<ref name="wired20130323"/>

The first near-Earth asteroid to be visited by a spacecraft was [[433 Eros]] when [[NASA]]'s ''[[NEAR Shoemaker]]'' probe orbited it from February 2000, landing on the surface of the {{convert|17|km|mi|abbr=on}} asteroid in February 2001.<ref name="Eros-NEAR">{{cite news |first1=Donald |last1=Savage |first2=Michael |last2=Buckley |name-list-style=amp |title=NEAR Mission Completes Main Task, Now Will Go Where No Spacecraft Has Gone Before |date=January 31, 2001 |work=Press Releases |publisher=NASA |url=http://nssdc.gsfc.nasa.gov/planetary/news/near_descent_pr_20010131.html |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20160617001709/http://nssdc.gsfc.nasa.gov/planetary/news/near_descent_pr_20010131.html |archive-date=June 17, 2016}}</ref> A second NEA, the {{convert|535|m|ft|abbr=on}} long peanut-shaped [[25143 Itokawa]], was explored from September 2005 to April 2007 by [[JAXA]]'s ''[[Hayabusa (spacecraft)|Hayabusa]]'' mission, which succeeded in taking material samples back to Earth.<ref name="Itokawa-hayabusa">{{cite web |title=Hayabusa. The Final Approach. Overview |publisher=JAXA |url=https://hayabusa.jaxa.jp/e/index.html |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20230602050007/https://hayabusa.jaxa.jp/e/index.html |archive-date=June 2, 2023}}</ref> A third NEA, the {{convert|2.26|km|mi|abbr=on}} long elongated [[4179 Toutatis]], was explored by [[China National Space Administration|CNSA]]'s ''[[Chang'e 2]]'' spacecraft during a flyby in December 2012.<ref name="Toutatis-Change">{{cite news |first=Emily |last=Lakdawalla |title=Chang'e 2 imaging of Toutatis |date=December 14, 2012 |publisher=[[The Planetary Society]] |url=https://www.planetary.org/articles/12141551-change-2-imaging-of-toutatis |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20241203034955/https://www.planetary.org/articles/12141551-change-2-imaging-of-toutatis |archive-date=December 3, 2024}}</ref><ref name="IAU-NEOs"/>

The {{convert|980|m|ft|abbr=on}} Apollo asteroid [[162173 Ryugu]] was explored from June 2018<ref name="arrival">{{Cite news |first=Stephen |last=Clark |title=Japanese spacecraft reaches asteroid after three-and-a-half-year journey |date=June 28, 2018 |work=Spaceflight Now |url=https://spaceflightnow.com/2018/06/28/japanese-spacecraft-reaches-asteroid-after-three-and-a-half-year-journey/ |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20231024060128/https://spaceflightnow.com/2018/06/28/japanese-spacecraft-reaches-asteroid-after-three-and-a-half-year-journey/ |archive-date=October 24, 2023}}</ref> until November 2019<ref name="Spacecom-Hayabusa2-2019">{{Cite news |first=Meghan |last=Bartels |title=Farewell, Ryugu! Japan's Hayabusa2 Probe Leaves Asteroid for Journey Home |date=November 13, 2019 |work=Space.com |url=https://www.space.com/hayabusa2-spacecraft-leaves-asteroid-ryugu.html |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20231024064540/https://www.space.com/hayabusa2-spacecraft-leaves-asteroid-ryugu.html |archive-date=October 24, 2023}}</ref> by JAXA's ''[[Hayabusa2]]'' space probe, which returned a sample to Earth.<ref name="BBC-Hayabusa2">{{Cite news |first=Paul |last=Rincon |title=Hayabusa-2: Capsule with asteroid samples in 'perfect' shape |date=December 6, 2020 |work=BBC News |publisher=BBC |url=https://www.bbc.com/news/science-environment-55201662 |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20231024064457/https://www.bbc.com/news/science-environment-55201662 |archive-date=October 24, 2023}}</ref> A second sample-return mission, NASA's ''[[OSIRIS-REx]]'' probe, targeted the {{convert|500|m|ft|abbr=on}} Apollo asteroid [[101955 Bennu]],<ref name="space-osiris-launch">{{cite news |first=Mike |last=Wall |title='Exactly Perfect'! NASA Hails Asteroid Sample-Return Mission's Launch |date=September 9, 2016 |work=Space.com |url=https://www.space.com/34020-nasa-hails-osiris-rex-asteroid-mission-launch.html |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20231006005439/https://www.space.com/34020-nasa-hails-osiris-rex-asteroid-mission-launch.html |archive-date=October 6, 2023}}</ref> which, {{As of|2025|1|lc=y}}, has the third-highest cumulative Palermo scale rating (−1.40 for several close encounters between 2178 and 2290).<ref name="Current_Impact_Risks"/> On its journey to Bennu, the probe had searched unsuccessfully for Earth's Trojan asteroids,<ref>{{cite news |first1=Erin |last1=Morton |first2=Nancy |last2=Neal-Jones |title=NASA's OSIRIS-REx Begins Earth-Trojan Asteroid Search |date=February 9, 2017 |work=News |publisher=NASA |url=https://www.nasa.gov/centers-and-facilities/goddard/nasas-osiris-rex-begins-earth-trojan-asteroid-search/ |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20241203115428/https://www.nasa.gov/centers-and-facilities/goddard/nasas-osiris-rex-begins-earth-trojan-asteroid-search/ |archive-date=December 3, 2024}}</ref> entered into orbit around Bennu in December 2018, touched down on its surface in October 2020,<ref name="space-osiris-overview">{{cite news |first=Nola |last=Taylor Tillman |title=OSIRIS-REx: A complete guide to the asteroid-sampling mission |date=September 25, 2023 |work=[[Space.com]] |url=https://www.space.com/33776-osiris-rex.html |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20240125154614/https://www.space.com/33776-osiris-rex.html |archive-date=January 25, 2024}}</ref> and was successful in returning samples to Earth three years later.<ref name="space-osiris-sample">{{cite news |first=John |last=Loeffer |title=NASA finally opens OSIRIS-REx asteroid sample canister after freeing stuck lid |date=January 23, 2024 |work=Space.com |url=https://www.space.com/nasa-osiris-rex-asteroid-sample-canister-open |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20240125183741/https://www.space.com/nasa-osiris-rex-asteroid-sample-canister-open |archive-date=January 25, 2024}}</ref> China plans to launch its own sample-return mission, ''[[Tianwen-2]]'', in May 2025, targeting Earth quasi-satellite {{mp|469219 Kamoʻoalewa|}} and returning samples to Earth in late 2027.<ref>{{cite web |title=Long March 3B/E. Tianwen 2 |work=[[NASASpaceFlight.com|Next Spaceflight]] |url=https://nextspaceflight.com/launches/details/4925 |access-date=January 3, 2025 |url-status=live |archive-url=https://web.archive.org/web/20240901130100/https://nextspaceflight.com/launches/details/4925 |archive-date=September 1, 2024}}</ref>

After completing its mission to Bennu, the probe ''OSIRIS-REx'' was redirected towards 99942 Apophis, which it is planned to orbit from April 2029.<ref name="space-osiris-overview"/> After completing its exploration of 162173 Ryugu, the mission of the ''Hayabusa2'' space probe was extended, to include flybys of S-type Apollo asteroid [[98943 Torifune]] in July 2026 and fast-rotating Apollo asteroid {{mpl|1998 KY|26}} in July 2031.<ref>{{Cite conference |last1=Hirabayashi |first1=Masatoshi |last2=Yoshikawa |first2=Makoto |last3=Mimasu |first3=Yuya |last4=Tanaka |first4=Satoshi |last5=Saiki |first5=Takanao |last6=Nakazawa |first6=Satoru |last7=Tsuda |first7=Yuichi |last8=Tatsumi |first8=Eri |last9=Popescu |first9=Marcel |last10=Pravec |first10=Petr |last11=Urakawa |first11=Seitaro |last12=Yoshida |first12=Fumi |last13=Hirata |first13=Naru |last14=Kamata |first14=Shunichi |last15=Kitazato |first15=Kohei |display-authors=2 |date=February 15, 2023 |title=Hayabusa2#'s Exploration to Asteroids 2001 CC21 and 1998 KY26 Provides Key Insights Into Planetary Defense |url=https://ntrs.nasa.gov/citations/20230002153 |conference=8th IAA Planetary Defense Conference |location=Vienna, Austria |archive-url=https://web.archive.org/web/20240123201919/https://ntrs.nasa.gov/citations/20230002153 |archive-date=January 23, 2024 |url-status=live}}</ref> In 2025, JAXA plans to launch another probe, ''[[DESTINY+]]'', to explore Apollo asteroid {{mpl|3200 Phaethon|}}, the parent body of the [[Geminids|Geminid meteor shower]], during a flyby.<ref name="space-20231106">{{cite news |first=Andrew |last=Jones |title=Japan's mission to bizarre asteroid Phaethon delayed to 2025 |date=November 6, 2023 |work=Space.com |url=https://www.space.com/japan-destiny-mission-asteroid-phaethon-launch-delay |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20250101103731/https://www.space.com/japan-destiny-mission-asteroid-phaethon-launch-delay |archive-date=January 1, 2025}}</ref>

==== Asteroid deflection tests ====
[[File:DART-impact-SAAO-Lesedi-Mookodi.gif|thumb|Spread of the plume from the impact of the [[Double Asteroid Redirection Test|DART]] space probe on asteroid moon [[Dimorphos]] ([[SAAO]])]]

On September 26, 2022, NASA's ''[[Double Asteroid Redirection Test|DART]]'' spacecraft reached the system of {{mpl|65803 Didymos|}} and impacted the Apollo asteroid's moon [[Dimorphos]], in a test of a method of [[Asteroid impact avoidance|planetary defense]] against near-Earth objects.<ref name="NASA220927">{{cite news |first=Roxana |last=Bardan |title=NASA's DART Mission Hits Asteroid in First-Ever Planetary Defense Test |date=September 27, 2022 |work=Press Releases |publisher=NASA |url=https://www.nasa.gov/news-release/nasas-dart-mission-hits-asteroid-in-first-ever-planetary-defense-test/ |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20250101142705/https://www.nasa.gov/news-release/nasas-dart-mission-hits-asteroid-in-first-ever-planetary-defense-test/ |archive-date=January 1, 2025}}</ref> In addition to telescopes on or in orbit around the Earth, the impact was observed by the Italian mini-spacecraft or [[CubeSat]] ''LICIACube'', which separated from ''DART'' 15 days before impact.<ref name="NASA220927"/> The impact shortened the orbital period of Dimorphos around Didymos by 33 minutes, indicating that the moon's momentum change was 3.6 times the momentum of the impacting spacecraft, thus most of the change was due to the ejected material of the moon itself.<ref name="NASA221215">{{cite news |first=Jessica |last=Merzdorf |title=Early Results from NASA's DART Mission |date=December 15, 2022 |work=Press Releases |publisher=NASA |url=https://www.nasa.gov/solar-system/early-results-from-nasas-dart-mission/ |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20250102153424/https://www.nasa.gov/solar-system/early-results-from-nasas-dart-mission/ |archive-date=January 2, 2025}}</ref>

In October 2024, ESA launched the spacecraft ''[[Hera (space mission)|Hera]]'', which is to enter orbit around Didymos in December 2026, to study the consequences of the DART impact.<ref>{{cite web |title=Hera |publisher=ESA |url=https://www.esa.int/Space_Safety/Hera |access-date=December 31, 2024 |url-status=live |archive-url=https://web.archive.org/web/20241231085805/https://www.esa.int/Space_Safety/Hera |archive-date=December 31, 2024}}</ref> China plans to launch its own pair of asteroid deflection and observation probes in 2027, which are to target {{convert|30|m|ft|abbr=on}} Aten asteroid {{mpl|2015 XF|261}}.<ref>{{cite web |first1=Andrew |last1=Jones |title=China targets its first planetary defense test mission |date=July 2, 2024 |publisher=The Planetary Society |url=https://www.planetary.org/articles/china-targets-its-first-planetary-defense-test-mission |access-date=January 3, 2025 |url-status=live |archive-url=https://web.archive.org/web/20241008065834/https://www.planetary.org/articles/china-targets-its-first-planetary-defense-test-mission |archive-date=October 8, 2024}}</ref>

==== Space mining ====

From the 2000s, there were plans for the commercial exploitation of near-Earth asteroids, either through the use of robots or even by sending private commercial astronauts to act as space miners, but few of these plans were pursued.<ref name="Forbes210831">{{Cite news |last=Dorminey |first=Bruce |title=Does Commercial Asteroid Mining Still Have A Future? |date=August 31, 2021 |work=[[Forbes]] |url=https://www.forbes.com/sites/brucedorminey/2021/08/31/does-commercial-asteroid-mining-still-have-a-future/ |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20240804082359/https://www.forbes.com/sites/brucedorminey/2021/08/31/does-commercial-asteroid-mining-still-have-a-future/ |archive-date=August 4, 2024}}</ref>

In April 2012, the company [[Planetary Resources]] announced its plans to [[Asteroid mining|mine asteroids]] commercially. In a first phase, the company reviewed data and selected potential targets among NEAs. In a second phase, space probes would be sent to the selected NEAs; mining spacecraft would be sent in a third phase.<ref name="ST-AsteroidMining">{{cite news |first=Kelly |last=Beatty |title=Asteroid Mining for Fun and Profit |date=April 24, 2012 |work=Sky & Telescope |url=http://www.skyandtelescope.com/astronomy-news/asteroid-mining-forfunandprofit/ |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20240912123200/https://skyandtelescope.org/astronomy-news/asteroid-mining-forfunandprofit/ |archive-date=September 12, 2024}}</ref> Planetary Resources launched two testbed satellites in April 2015<ref name="Arkyd6LeftBuilding"/> and January 2018,<ref>{{cite news |title=Planetary Resources Launches Latest Spacecraft in Advance of Space Resource Exploration Mission |date=January 12, 2018 |work=News |publisher=Planetary Resources |url=https://www.planetaryresources.com/2018/01/planetary-resources-launches-latest-spacecraft-in-advance-of-space-resource-exploration-mission/ |access-date=January 13, 2018 |url-status=dead |archive-url=https://web.archive.org/web/20180113093243/https://www.planetaryresources.com/2018/01/planetary-resources-launches-latest-spacecraft-in-advance-of-space-resource-exploration-mission/ |archive-date=January 13, 2018}}</ref> and the first prospecting satellite for the second phase was planned for a 2020 launch prior to the company closing and its assets purchased by ConsenSys Space in 2018.<ref name="Arkyd6LeftBuilding">{{cite news |first=Alan |last=Boyle |title=Planetary Resources' Arkyd-6 prototype imaging satellite has left the building |date=November 13, 2017 |work=[[GeekWire]] |url=https://www.geekwire.com/2017/planetary-resources-arkyd-6-prototype-imaging-satellite-left-building/ |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20171114080201/https://www.geekwire.com/2017/planetary-resources-arkyd-6-prototype-imaging-satellite-left-building/ |archive-date=November 14, 2017}}</ref><ref name="oneyearsinceplanetaryresources">{{cite news |first=Alan |last=Boyle |title=One year after Planetary Resource faded into history, space mining retails its appeal |date=November 4, 2019 |work=GeekWire |url=https://www.geekwire.com/2019/one-year-planetary-resources-faded-history-space-mining-retains-appeal/ |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20231014085126/https://www.geekwire.com/2019/one-year-planetary-resources-faded-history-space-mining-retains-appeal/ |archive-date=October 14, 2023}}</ref>

Another American company established with the goal of space mining, [[AstroForge]], launched the probe ''Odin'' (formerly ''Brokkr-2'') on February 26, 2025, to perform a flyby of asteroid {{mpl|2022 OB|5}}, but the probe showed technical problems.<ref name="Odin-launch-problems">{{cite news |first=Tariq |last=Malik |title='I think we all know that hope is fading.' Private Odin asteroid probe is tumbling in space |date=March 1, 2025 |work=Space.com |url=https://www.space.com/space-exploration/private-spaceflight/i-think-we-all-know-that-hope-is-fading-private-odin-asteroid-probe-is-tumbling-in-space |access-date=March 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20250301230617/https://www.space.com/space-exploration/private-spaceflight/i-think-we-all-know-that-hope-is-fading-private-odin-asteroid-probe-is-tumbling-in-space |archive-date=March 1, 2025}}</ref> The  goal of the mission was to confirm if {{mp|2022 OB|5}} is a metal-rich [[M-type asteroid]].<ref>{{Cite news |first=Alex |last=Knapp |title=This Asteroid Mining Startup Is Ready To Launch The First-Ever Commercial Deep Space Mission |date=October 18, 2023 |work=Forbes |url=https://www.forbes.com/sites/alexknapp/2023/10/18/this-asteroid-mining-startup-is-ready-to-launch-the-first-ever-commercial-deep-space-mission/ |access-date=January 3, 2025 |url-status=live |archive-url=https://web.archive.org/web/20241123112719/https://www.forbes.com/sites/alexknapp/2023/10/18/this-asteroid-mining-startup-is-ready-to-launch-the-first-ever-commercial-deep-space-mission/ |archive-date=November 23, 2024}}</ref> Regardless of the success of ''Odin'', AstroForge plans  to follow it up a year later with the probe ''Vestri'', which is to land on the same asteroid.<ref name="Odin-launch-problems"/>

=== Missions to NECs ===
[[File:67P Churyumov-Gerasimenko - Rosetta (32755885495).png|thumb|Nucleus of comet [[67P/Churyumov–Gerasimenko]] as seen by ESA's ''[[Rosetta (spacecraft)|Rosetta]]'' probe]]

The first near-Earth comet visited by a space probe was [[21P/Giacobini–Zinner]] in 1985, when the NASA/ESA probe ''[[International Cometary Explorer]]'' (''ICE'') passed through its coma. In March 1986, ICE, along with [[Soviet Union|Soviet]] probes ''[[Vega 1]]'' and ''[[Vega 2]]'', [[Institute of Space and Astronautical Science|ISAS]] probes ''[[Sakigake]]'' and ''[[Suisei (spacecraft)|Suisei]]'' and ESA probe ''[[Giotto (spacecraft)|Giotto]]'' flew by the nucleus of Halley's Comet. In 1992, ''Giotto'' also visited another NEC, [[26P/Grigg–Skjellerup]].<ref name="TaskForceReport"/>

In November 2010, after completing its primary mission to non-near-Earth comet [[Tempel 1]], the NASA probe ''[[Deep Impact (spacecraft)|Deep Impact]]'' flew by the near-Earth comet [[103P/Hartley]].<ref name="DeepImpactHartley">{{Cite news |title=Mr. Hartley's Amazing Comet |first=Kelly |last=Beatty |date=November 4, 2010 |work=[[Sky & Telescope]] |url=https://skyandtelescope.org/astronomy-news/mr-hartleys-amazing-comet/ |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20231020025244/https://skyandtelescope.org/astronomy-news/mr-hartleys-amazing-comet/ |archive-date=October 20, 2023}}</ref>

In August 2014, ESA probe ''Rosetta'' began orbiting near-Earth comet [[67P/Churyumov–Gerasimenko]], while its lander ''[[Philae (spacecraft)|Philae]]'' landed on its surface in November 2014. After the end of its mission, Rosetta was crashed into the comet's surface in 2016.<ref name="newsci20160930">{{cite news |first=Jacob |last=Aron |title=Rosetta lands on 67P in grand finale to two year comet mission |date=September 30, 2016 |work=[[New Scientist]] |url=https://www.newscientist.com/article/2107585-rosetta-lands-on-67p-in-grand-finale-to-two-year-comet-mission/ |access-date=January 2, 2025 |url-status=live |archive-url=https://web.archive.org/web/20241203014854/https://www.newscientist.com/article/2107585-rosetta-lands-on-67p-in-grand-finale-to-two-year-comet-mission/ |archive-date=December 3, 2024}}</ref>
{{clear}}