{{Short description|Periodic contact binary comet}} {{Use American English|date=January 2019}} {{Use dmy dates|date=November 2019}} {{Infobox planet | name = 67P/Churyumov–Gerasimenko | pronounced = {{IPAc-en|,|ch|Vr|i|'|u:|m|Q|f|_|dZ|Er|,|ae|s|i|'|m|E|N|k|ou|,_|,|g|Er|@|s|i|-}}<ref name=ISSI>International Space Science Institute (2020) "Rosetta at Comet Nucleus 67P/Churyumov-Gerasimenko with Jessica Agarwal"</ref><ref>News Direct (2014) "Rosetta spacecraft ready to land on Comet 67P/Churyumov–Gerasimenko"</ref> | image = File:Comet 67P True color.jpg | image_scale = | caption = Comet 67P/Churyumov–Gerasimenko in true colour, as seen by ESA's ''Rosetta'' spacecraft in December 2014 | discoverer = Klim Ivanovich Churyumov<br/>{{Nowrap|Svetlana Ivanovna Gerasimenko}} | discovered = 20 September 1969 | discovery_site = Almaty, Kazakh SSR, Soviet Union<br/>Kyiv, Ukrainian SSR, Soviet Union | alt_names = 1969 R1, 1969 IV, 1969h, 1975 P1, 1976 VII, 1975i, 1982 VIII, 1982f, 1989 VI, 1988i<ref name="jpldata"/><br>"Chury" {{IPAc-en|'|ch|Vr|i}}<ref name=ISSI/> | orbit_ref = <ref name="MPC"/> | epoch = 25 February 2023 (JD 2460000.5) | aphelion = {{convert|5.704|AU|e6km e6mi|disp=x|abbr=unit|<br/>{{in5}}<small>(|)</small>}} | perihelion = {{convert|1.210|AU|e6km e6mi|disp=x|abbr=unit|<br/>{{in5}}<small>(|)</small>}} | semimajor = {{convert|3.457|AU|e6km e6mi|disp=x|abbr=unit|<br/>{{in5}}<small>(|)</small>}} | eccentricity = 0.64989 | period = 6.43 yr | inclination = 3.8719° | asc_node = 36.33° | mean_anomaly = 73.57° | arg_peri = 22.15° | time_periastron = 9 April 2028<ref name="Horizons2028"/><br/>2 November 2021 (previous)<ref name="Yoshida"/><ref name=MPC/> | dimensions = {{Plainlist| * Large lobe: {{cvt|4.1|x|3.3|x|1.8|km|1|disp=x|<br/>(|)}}<ref name="esa20150122"/> * Small lobe: {{convert|2.6|x|2.3|x|1.8|km|1|disp=x|<br/>(|)}}<ref name="esa20150122"/> }} | volume = {{cvt|18.7|km3}}<ref name="mass density 2016"/> | mass = {{val|9.982|0.003|e=12|u=kg}}<ref name="mass density 2016"/> | density = {{cvt|0.533|±|0.006|g/cm3|lb/in3|disp=x| <ref name="mass density 2016"/><ref name="Lakdawalla1118"/><br/>{{in5}}<small>(|)</small>}} | escape_velocity = ''est.'' 1 m/s<ref name="mpg20140121"/> | sidereal_day = {{val|12.4043|0.0007|u=hours}}<ref name="Mottola2014"/> | right_asc_north_pole = 69.3°<ref name="esa20150122"/> | declination = 64.1°<ref name="esa20150122"/> | axial_tilt = 52°<ref name="esa20150122"/> | albedo = 0.06<ref name="esa20150122"/> | temp_name1 = Kelvin | min_temp_1 = {{0|−}}180 | max_temp_1 = {{0|−}}230 | temp_name2 = Celsius | min_temp_2 = {{0}}−93 | max_temp_2 = {{0}}−43 | temp_name3 = Fahrenheit | min_temp_3 = −135 | max_temp_3 = {{0}}−45 }}
'''67P/Churyumov–Gerasimenko''' (abbreviated '''67P''' or '''67P/C–G''' and nicknamed "Chury"<ref name=ISSI/>) is a Jupiter-family comet.<ref name="yfernandez"/> It is originally from the Kuiper belt<ref name="AP-20141210-SB"/> and has an orbital period of 6.45 years as of 2012,<ref name=jpldata/> a rotation period of approximately 12.4 hours,<ref name="Mottola2014"/> and a maximum velocity of {{cvt|135000|kph|km/s mph}}.<ref name="ESA-faq"/> Churyumov–Gerasimenko is approximately {{cvt|4.3|by|4.1|km}} at its longest and widest dimensions.<ref name="67P_size"/> It was first observed on photographic plates in 1969 by Soviet astronomers Klim Ivanovych Churyumov and Svetlana Ivanovna Gerasimenko, after whom it is named.{{efn|Both names are stressed on their penultimate syllable. In Ukrainian, the pronunciations are {{IPA|uk|tʃʊˈrʲumov ˌʕɛrɐsɪˈmɛŋko|}}, approximately ''churyúmov hèrasiménko'', with the ''g'' a bit like an English ''h'' or a French or German ''r''.}} It most recently came to perihelion (closest approach to the Sun) on 2 November 2021,<ref name=MPC/><ref name="Yoshida"/><ref name=Kinoshita/> and will next come to perihelion on 9 April 2028.<ref name="Horizons2028"/>
Churyumov–Gerasimenko was the destination of the European Space Agency's ''Rosetta'' mission, launched on 2 March 2004.<ref name=Krolikowska2003/><ref name="NASA-201401017"/><ref name="NYT-20140805"/> ''Rosetta'' rendezvoused with Churyumov–Gerasimenko on 6 August 2014<ref name="Fischer2014-08-06"/><ref name="Bauer2014"/> and entered orbit on 10 September 2014.<ref name="esa20140910"/> ''Rosetta''{{'s}} lander, ''Philae'', landed on the comet's surface on 12 November 2014, becoming the first spacecraft to land on a comet nucleus.<ref name="NASA-20141112-DCA"/><ref name="NYT-20141112-KC"/><ref name=bbcland/> On 30 September 2016, the ''Rosetta'' spacecraft ended its mission by landing on the comet in its Ma{{ayin}}at region.<ref name="newsci20160930"/><ref name="space20160930"/>
== Discovery == Churyumov–Gerasimenko was discovered in 1969 by Klim Ivanovich Churyumov of Kyiv University's Astronomical Observatory,<ref name="iau61"/> who examined a photograph that had been exposed for comet Comas Solà by Svetlana Ivanovna Gerasimenko on 11 September 1969 at the Alma-Ata Astrophysical Institute, near Alma-Ata, the then-capital city of Kazakh Soviet Socialist Republic, Soviet Union. Churyumov found a cometary object near the edge of the plate, but assumed that this was comet Comas Solà.<ref name="Kronk"/>
After returning to his home institute in Kyiv, Churyumov examined all the photographic plates more closely. On 22 October, about a month after the photograph was taken, he discovered that the object could not be Comas Solà, because it was about 1.8 degrees off the expected position. Further scrutiny produced a faint image of Comas Solà at its expected position on the plate, thus proving the other object to be a different body.<ref name="Kronk"/>
== Shape == [[File:Comet 67P-Churyumov-Gerasimenko.stl|left|thumb|3D model of 67P by ESA (click to rotate)]] The comet consists of two lobes connected by a narrower neck, with the larger lobe measuring about {{cvt|4.1|x|3.3|x|1.8|km|1}} and the smaller one about {{cvt|2.6|x|2.3|x|1.8|km|1}}.<ref name="esa20150122"/> With each orbit the comet loses matter, as gas and dust are evaporated away by the Sun. It is estimated that a layer with an average thickness of about {{cvt|1|±|0.5|m|ft}} is lost per orbit as of 2015.<ref name="Bertaux2015"/> The comet has a mass of approximately 10 billion tonnes.<ref name="mass density 2016"/>
The two-lobe shape of the comet is the result of a gentle, low-velocity collision of two objects, and is called a contact binary. The "terraces", layers of the interior of the comet that have been exposed by partial stripping of outer layers during its existence, are oriented in different directions in the two lobes, indicating that two objects fused to form Churyumov–Gerasimenko.<ref name="natgeo20150928"/><ref name="Massironi2015"/>
A high-resolution photogrammetric shape model of the nucleus, featuring 132.1 million facets, was reconstructed using 7,682 NAC and 1,504 WAC images from the OSIRIS cameras taken post-perihelion. This model enabled the first detailed description and thermal modeling of Subsurface Access Points (SAPs)—cavities ranging from 20 to 47 meters in depth that provide direct access to the comet's subsurface. The study established a correlation between the energy threshold received at the bottom of these SAPs and the onset of transient sublimation jets. These sites are considered primary targets for future sample-return missions seeking pristine material beneath the surface crust <ref>{{cite journal |last1=Lamy |first1=Philippe |last2=Faury |first2=Guillaume |last3=Romeuf |first3=David |last4=Groussin |first4=Olivier |title=Detection and characterization of icy cavities on the nucleus of comet 67P/Churyumov–Gerasimenko |journal=Monthly Notices of the Royal Astronomical Society |date=June 2024 |volume=531 |issue=2 |pages=2494–2516 |doi=10.1093/mnras/stae1290 |doi-access=free |url=https://academic.oup.com/mnras/article/531/2/2494/7680008}}. Video visualization: [https://www.youtube.com/watch?v=ztZ2d3laOQA 3D stereoscopic] and [https://www.youtube.com/watch?v=RJYOGgD4bo4 2D version] via YouTube.</ref>.
== Surface == [[File:67P Churyumov-Gerasimenko surface.gif|alt=A black-and-white short animation of dust on the surface|thumb|Dust and cosmic rays on the surface of the comet in 2016, with stars moving in the background. Filmed by ''Rosetta''{{'}}s OSIRIS instrument]]
alt=Pristine view of 67P|thumb|Pristine view (B) of 67P after removal of noise and outliers from the surface using advanced outlier removal techniques. (C) shows the flakes when treated as outliers in the original raw image (A).
There are 26 distinct regions on Churyumov–Gerasimenko, with each named after an Egyptian deity; regions on the large lobe are named after gods, whereas those on the small lobe are named after goddesses. Nineteen regions were defined in the northern hemisphere prior to equinox.<ref name="ElMaarry2015"/><ref name="space20150719"/> Later, when the southern hemisphere became illuminated, seven more regions were identified using the same naming convention.<ref name="ElMaarry2016"/><ref name="esa20160224"/> {{clear|left}} {| class="wikitable" |- ! Region|| Terrain ||Region|| Terrain ||Region|| Terrain |- | Ma{{ayin}}at|| Dust covered | Ash|| Dust covered | Babi|| Dust covered |- | Seth|| Pitted and brittle material | Hatmehit|| Large-scale depression | Nut|| Large-scale depression |- | Aten|| Large-scale depression | Hapi|| Smooth | Imhotep|| Smooth |- | Anubis|| Smooth | Maftet|| Rock-like | Bastet|| Rock-like |- | Serqet|| Rock-like | Hathor|| Rock-like | Anuket|| Rock-like |- | Khepry|| Rock-like | Aker|| Rock-like | Atum|| Rock-like |- | Apis|| Rock-like | Khonsu|| Rock-like | Bes|| Rock-like |- | Anhur|| Rock-like, rather friable | Geb|| Rock-like | Sobek|| Rock-like |- | Neith|| Rock-like | Wosret|| Rock-like |}
=== Gates === Features described as ''gates'', twin prominences on the surface so named for their appearance,{{Clarify|date=October 2015|reason=could use an image, anything actually looking like a gate would be exceedingly weird}} were named after deceased members of the ''Rosetta'' team.<ref name="esablog20150928"/> {| class="wikitable" |- ! Name !! Named after |- | C. Alexander Gate || Claudia Alexander |- | A. Coradini Gate || Angioletta Coradini |}
=== Surface changes === During ''Rosetta''{{'s}} lifetime, many changes were observed on the comet's surface, particularly when the comet was close to perihelion.<ref name="ElMaarry2017"/><ref name="esa20170321"/><ref name="nasa20170321"/> These changes included evolving patterns of circular shapes in smooth terrains that at some point grew in size by a few meters per day.<ref name="Groussin2015"/><ref name="esa20150918"/> A fracture in the neck region was also observed to grow in size; boulders tens of meters wide were displaced, sometimes travelling more than 100 meters; and patches of the ground were removed to expose new features. A number of collapsing cliffs have also been observed. One notable example in December 2015 was captured by ''Rosetta''{{'s}} NAVCAM as a bright patch of light shining from the comet. ''Rosetta'' scientists determined that a large cliff had collapsed, making it the first landslide on a comet known to be associated with an outburst of activity.<ref name="Pajola2017"/><ref name="wapo20170321"/> An apparent outburst of the comet was observed on 14 November 2021.<ref name="AST-20211119">{{cite news |author=Kelley, Michael S. P. |title=ATel #15053 – Apparent Outburst of Comet 67P/Churyumov-Gerasimenko |url=https://www.astronomerstelegram.org/?read=15053 |date=19 November 2021 |work=The Astronomer's Telegram |access-date=20 November 2021 }}</ref> According to the researchers, "At the time of the outburst discovery with ZTF, the comet was 1.23 au from the Sun and 0.42 au from the Earth. The comet's last perihelion passage was on 2021 Nov 2.".<ref name="AST-20211119"/>
=== Cheops boulder === Cheops is the largest boulder on the surface of the comet, measuring up to 45 meters. It is located in the comet's larger lobe. It was named for the pyramid in Giza because its shape is similar to that of a pyramid.<ref>{{cite news |title=Boulder Cheops |author=ESA|url=https://sci.esa.int/web/rosetta/-/54756-boulder-cheops |date=1 September 2019}}</ref><ref>{{cite web |author=ANI |title=Largest boulders on Rosetta's comet named after Egyptian pyramid 'Cheops' |url=https://in.news.yahoo.com/largest-boulders-rosettas-comet-named-egyptian-pyramid-cheops-085102345.html |website=Yahoo News |access-date=19 October 2020}}</ref><ref>{{cite web |last=Howell |first=Elizabeth |title=Rosetta Spacecraft Spots 'Pyramid' Boulder on Comet (Photos) |url=https://www.space.com/27420-rosetta-spacecraft-comet-boulder-photos.html |website=Space.com |date=13 October 2014 |access-date=19 October 2020}}</ref>
== Orbit and rotation == {| class=wikitable style="text-align:center; font-size:11px; float:right; margin:2px" |- bgcolor= style="font-size: smaller;" | colspan="8" style="text-align:center;"|'''Perihelion distance<br/>at different epochs'''<ref name="Kinoshita"/> |- ! Epoch !! Perihelion<br/>(AU) |- | 1821 || 2.44 |- | 1882 || 2.94 |- | 1956 || 2.74 |- | 1963 || 1.28 |- | 2021 || 1.21 |- | 2101 || 1.35 |- | 2223 || ≈ 0.8<ref name="Horizons2223"/> |}
left|thumb|The orbit of 67P/Churyumov–Gerasimenko moves from just inside the orbit of Mars to just outside the orbit of Jupiter, seen here at perihelion in August 2015. thumb|upright|This animation consists of 86 images acquired by ''Rosetta''{{'s}} NavCam as it approached 67P in August 2014. Like the other comets of the Jupiter family, Churyumov–Gerasimenko probably originated in the Kuiper belt and was ejected towards the interior of the Solar System, where later encounters with Jupiter successively changed its orbit. These interactions will continue until the comet is eventually thrown out of the Solar System or collides with the Sun or a planet.
On 4 February 1959, a close encounter with Jupiter of {{convert|0.0515|AU|e6km|abbr=unit|lk=on}}<ref name="jpldata"/> moved Churyumov–Gerasimenko's perihelion inward from {{convert|2.7|AU|e6km|abbr=unit}} to {{convert|1.28|AU|e6km|abbr=unit}}, where it basically remains today.<ref name="Kinoshita"/> In November 2220 the comet will pass about {{convert|0.14|AU|e6km|abbr=unit}} from Jupiter<ref name="Dunn"/> which will move perihelion inwards to about {{convert|0.8|AU|e6km|abbr=unit}} from the Sun.<ref name="Horizons2223"/>
Before Churyumov–Gerasimenko's perihelion passage in 2009, its rotational period was 12.76 hours. During this perihelion passage, it decreased to 12.4 hours, which likely happened because of sublimation-induced torque.<ref name="Mottola2014"/>
=== 2015 perihelion === {{As of|2014|9}}, Churyumov–Gerasimenko's nucleus had an apparent magnitude of roughly 20.<ref name="MPC"/> It came to perihelion on 13 August 2015.<ref name="Yoshida"/><ref name="AP-20150813"/> From December 2014 until September 2015, it had an elongation less than 45 degrees from the Sun.<ref name="MPC-emp"/> On 10 February 2015, it went through solar conjunction when it was 5 degrees from the Sun and was {{convert|3.3|AU|e6km|abbr=unit}} from Earth.<ref name="MPC-emp"/> It crossed the celestial equator on 5 May 2015 and became easiest to see from the Northern Hemisphere.<ref name="MPC-emp"/> Even right after perihelion when it was in the constellation of Gemini, it only brightened to about apparent magnitude 12, and required a telescope to be seen.<ref name="Yoshida"/> {{As of|2016|07}}, the comet had a total magnitude of about 20.<ref name="MPC"/> {{clear|left}}
=== 2021 perihelion === [[File:67P 2021-11-11 image ZTF-sso-616-zr-fov-13arcmin.png|thumb|The comet on 11 November 2021 by ZTF]] The 2021 apparition marked the closest approach to Earth since 1982.<ref name="jpldata"/> The comet reached perihelion on 2 November 2021<ref name="Yoshida"/> and the closest approach to Earth was on November 12, 2021, at 00:50 UTC, at a distance of 38 million miles (61 million km).<ref name="earthsky2021"/> The comet brightened to an apparent magnitude of 9, meaning it was visible with amateur telescopes.<ref name="earthsky2021">{{cite web |last=Irizarry |first=Eddie |title=Heads up! Famous comet 67P/C-G nearly closest |url=https://earthsky.org/astronomy-essentials/famous-comet-67p-c-g-closest-nov-2021-until-2214/ |website=earthsky.org |access-date=17 July 2023 |date=26 October 2021}}</ref><ref>{{cite web |last=Olason |first=Mike |title=COMET 67P/CHURYUMOV-GERASIMENKO ON 2021 NOVEMBER 15 |url=https://skyandtelescope.org/online-gallery/comet-67p-churyumov-gerasimenko-on-2021-november-15/ |website=skyandtelescope.org |access-date=17 July 2023 |date=2021-11-24}}</ref> Two outbursts were observed during the apparition, on 2021 October 29.940 and November 17.864 UTC, −3.12 days and +15.81 days, respectively, from the perihelion date. During the first outburst the comet brightened by 0.26 ± 0.03 mag in the outburst, with a 27% increase in the effective geometric cross-section and total outburst dust mass of {{val|5.3|e=5|u=kg}}. The second outburst caused a brightening of 0.49 ± 0.08 mag with effective geometric cross-section and total outburst dust mass 2.5 times larger than the first event.<ref>{{cite journal |last1=Sharma |first1=Kritti |last2=Kelley |first2=Michael S. P. |last3=Joharle |first3=Simran |last4=Kumar |first4=Harsh |last5=Swain |first5=Vishwajeet |last6=Bhalerao |first6=Varun |last7=Anupama |first7=G. C. |last8=Barway |first8=Sudhanshu |title=Outbursts of Comet 67P/Churyumov-Gerasimenko |journal=Research Notes of the AAS |date=3 December 2021 |volume=5 |issue=12 |pages=277 |doi=10.3847/2515-5172/ac3ee4|bibcode=2021RNAAS...5..277S |doi-access=free }} Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence.</ref>
== Exploration == === ''Rosetta'' mission === {{Main|Rosetta (spacecraft)|Philae (spacecraft)}} {{See also|Timeline of Rosetta spacecraft}} The ''Rosetta'' mission was the first mission to include an orbiter that accompanied a comet for several years, as well as a lander that collected close-up data from the comet's surface. The mission launched in 2004, arrived at comet 67P in 2014, and concluded with a touchdown on the comet's surface in 2016.
==== Advance work ==== {{multiple image |align=right |direction=horizontal |total_width=440 |image1=Rosetta's first sighting of its target in 2014 – narrow angle view (14813677376).jpg |caption1=First image of comet taken by ''Rosetta'' on 21 March 2014, with Messier 107 in view |image2=Comet 67P on 14 July 2014 OSIRIS, processed.png |caption2=Processed view of comet from 14 July 2014, showing the first indication of its bilobate nature }} As preparation for the ''Rosetta'' mission, Hubble Space Telescope pictures taken on 12 March 2003 were closely analysed. An overall 3D model was constructed and computer-generated images were created.<ref name="STScI-2003-26"/>
On 25 April 2012, the most detailed observations until that time were taken with the 2-meter Faulkes Telescope by N. Howes, G. Sostero and E. Guido while it was at its aphelion.{{citation needed|date=August 2015}}
On 6 June 2014, water vapor was detected being released at a rate of roughly {{convert|1|L/s|USgal/s|abbr=off}} when ''Rosetta'' was {{cvt|360000|km}} from Churyumov–Gerasimenko and {{convert|3.9|AU|e6km|abbr=unit}} from the Sun.<ref name="blog140623"/><ref name="NASA-20140630"/> On 14 July 2014, images taken by ''Rosetta'' showed that its nucleus is irregular in shape with two distinct lobes.<ref name="astronomy20140717"/> The size of the nucleus was estimated to be {{cvt|3.5|x|4|km}}.<ref name="skytel20140717"/> Two explanations for its shape were proposed at the time: that it was a contact binary, or that its shape may have resulted from asymmetric erosion due to ice sublimating from its surface to leave behind its lobed shape.<ref name="NYT-20140805"/><ref name="Bauer2014"/> By September 2015, mission scientists had determined that the contact binary hypothesis was unambiguously correct.<ref name="Massironi2015"/><ref name="esa20150928"/>
==== Rendezvous and orbit ==== {{multiple image |align=right |direction=horizontal |total_width=440 |image1=Animation of Rosetta trajectory.gif |caption1=Animation of ''Rosetta''{{'s}} trajectory from {{nowrap|2 March}} 2004 to {{nowrap|9 September}} 2016<br/>{{legend2|magenta|''Rosetta''}}{{·}}{{legend2|lime|67P}}{{·}}{{legend2|blue|Earth}}{{·}}{{legend2|maroon|Mars}}{{��}}{{legend2|Cyan|21 Lutetia}}{{·}}{{legend2|Gold|2867 Šteins}} |image2=Animation of Rosetta trajectory around 67P.gif |caption2=Animation of ''Rosetta''{{'s}} orbit around 67P from {{nowrap|1 August}} 2014 to {{nowrap|31 March}} 2015<br/>{{legend2|magenta|''Rosetta''}}{{·}}{{legend2|Lime|67P}} }} Beginning in May 2014, ''Rosetta''{{'s}} velocity was reduced by {{cvt|780|m/s|kph mph}} with a series of thruster firings.<ref name="NYT-20140805"/><ref name="csm20140804"/> Ground controllers rendezvoused ''Rosetta'' with Churyumov–Gerasimenko on 6 August 2014.<ref name="Fischer2014-08-06"/><ref name="Bauer2014"/> This was done by reducing ''Rosetta''{{'s}} relative velocity to {{cvt|1|m/s|kph mph|sigfig=1}}. ''Rosetta'' entered orbit on 10 September, at about {{cvt|30|km}} from the nucleus.<ref name="Fischer2014-08-06"/><ref name="Bauer2014"/><ref name="Lakdawalla2014-08-15"/>
==== Landing ==== {{Further|topic=the comet landing|Philae (spacecraft)#Mission}} Descent of a small lander occurred on 12 November 2014. ''Philae'' is a {{cvt|220|lb|order=flip}} robotic probe that set down on the surface with landing gear.<ref name="NYT-20140805"/><ref name="NYT-20141110-KC"/> The landing site has been christened ''Agilkia'' in honor of Agilkia Island, where the temples of Philae Island were relocated after the construction of the Aswan Dam flooded the island.<ref name="bbcnews20141104"/> The acceleration due to gravity on the surface of Churyumov–Gerasimenko has been estimated for simulation purposes at 10<sup>−3</sup> m/s{{sup|2}},<ref name="Hilchenbach2004"/> or about 1/10,000 of that on Earth.
Because of its low relative mass, landing on the comet relied on tools to anchor ''Philae'' to the surface. The probe had an array of mechanisms designed to manage Churyumov–Gerasimenko's low gravity, including a cold gas thruster, harpoons, landing-leg-mounted ice screws, and a flywheel to keep it oriented during its descent.<ref name="cnn20141113"/><ref name="register20141112"/><ref name="discovery20141112"/> During the event, the thruster and the harpoons failed to operate, and the ice screws did not gain a grip. The lander bounced twice and only came to rest when it made contact with the surface for the third time,<ref name="NASA-20141113-DCA"/> two hours after first contact.<ref name="skytel20141112"/>
Contact with ''Philae'' was lost on 15 November 2014 because of dropping battery power. The European Space Operations Centre briefly reestablished communications on 14 June 2015 and reported a healthy spacecraft but communications were lost again soon after.<ref name="nature20150614"/> On 2 September 2016, ''Philae'' was located in photographs taken by the ''Rosetta'' orbiter. It had come to rest in a crack with only its body and two legs visible. While the discovery solves the question of the lander's disposition, it also allows project scientists to properly contextualise the data it returned from the comet's surface.<ref name="skytel20160905"/>
=== Locating Philae === thumb|left|OSIRIS-NAC image showing the Hatmehit basin and the Philae landing zone. thumb|Pre- and post-landing OSIRIS-NAC images. The breakthrough in finding Philae occurred by comparing these images under identical illumination conditions.
Following Philae's bouncing touchdown in November 2014, finding its exact location on the comet proved to be a major challenge. Measurements from the CONSERT instrument made it possible to locate Philae within an ellipse measuring approximately 16 x 160 m. Complementary analyses by CNES-SONC further narrowed down the theoretical location based on illumination conditions and times of contact between the orbiter and lander.
The localization of Philae was the result of a long-term collective effort. By April 2015, the image of the lander was successfully identified among several candidates through an in-depth analysis of OSIRIS-NAC data by Guillaume Faury. The breakthrough was achieved when a pre-landing image from the OSIRIS-NAC collection was found to have geometric conditions (illumination and viewing angles) very similar to a post-landing image taken in mid-December 2014. All topographic details matched perfectly between the two images, except for one bright spot—about two pixels wide—present only on the post-landing image.
Although initially referred to as the "red candidate" in early ESA communications, its position was entirely consistent with the trajectory, solar illumination, and radio visibility models <ref>This valid candidate was initially identified and proposed by engineer Guillaume Faury and astrophysicist Philippe Lamy in April 2015. See: {{cite web |title=The quest to find Philae |url=https://blogs.esa.int/rosetta/2015/06/11/the-quest-to-find-philae-2/ |website=ESA Rosetta Blog |date=June 11, 2015}}.</ref>. The candidate was definitively confirmed as the Philae lander in September 2016, when the Rosetta spacecraft flew close enough to capture very high-resolution images of the probe resting in a dark crevice <ref>{{cite web |title=The story behind finding Philae |url=https://blogs.esa.int/rosetta/2016/09/28/the-story-behind-finding-philae/ |website=ESA Rosetta Blog |date=September 28, 2016}}.</ref>.
==== Physical properties ==== thumb|False-colour image of the comet outgassing, 15 April 2015 The composition of water vapor from Churyumov–Gerasimenko, as determined by the ''Rosetta'' spacecraft, is substantially different from that found on Earth. The ratio of deuterium to hydrogen in the water from the comet was determined to be three times that found for terrestrial water. This makes it unlikely that water found on Earth came from comets like Churyumov–Gerasimenko.<ref name="AP-20141210-SB"/><ref name="NASA-20141210-DCA"/><ref name="NYT-20141210-KC"/> The water vapor is also mixed with significant amount of formaldehyde (0.5 wt%) and methanol (0.4 wt%), these concentrations falling within common range for Solar system comets.<ref>{{cite journal |last1=Schuhmann |first1=Markus |last2=Altwegg |first2=Kathrin |author2-link=Kathrin Altwegg |last3=Balsiger |first3=Hans |last4=Berthelier |first4=Jean-Jacques |last5=De Keyser |first5=Johan |last6=Fuselier |first6=Stephen A. |last7=Gasc |first7=Sébastien |last8=Gombosi |first8=Tamas I. |last9=Hänni |first9=Nora |last10=Rubin |first10=Martin |last11=Sémon |first11=Thierry |last12=Tzou |first12=Chia-Yu |last13=Wampfler |first13=Susanne F. |year=2020 |title=CHO-bearing molecules in Comet 67P/Churyumov-Gerasimenko |journal=ACS Earth and Space Chemistry |volume=3 |issue=9 |page=1854 |arxiv=2003.03967 |bibcode=2019ESC.....3.1854S |doi=10.1021/acsearthspacechem.9b00094 |s2cid=201228823}}</ref> On 22 January 2015, NASA reported that, between June and August 2014, the comet released increasing amounts of water vapor, up to tenfold as much.<ref name="NASA-20150122"/> On 23 January 2015, the journal ''Science'' published a special issue of scientific studies related to the comet.<ref name="SCI-20150123"/>
Measurements carried out before ''Philae''{{'s}} batteries failed indicate that the dust layer could be as much as {{cvt|20|cm|0}} thick. Beneath that is hard ice, or a mixture of ice and dust. Porosity appears to increase toward the center of the comet.<ref name="esa20141218"/>
The nucleus of Churyumov–Gerasimenko was found to have no magnetic field of its own after measurements were taken during ''Philae''{{'s}} descent and landing by its ROMAP instrument and ''Rosetta''{{'s}} RPC-MAG instrument. This suggests that magnetism may not have played a role in the early formation of the Solar System, as had previously been hypothesized.<ref name="esa20150414"/><ref name="nature20150414"/>
The ALICE spectrograph on ''Rosetta'' determined that electrons (within {{cvt|1|km|1|disp=or}} above the comet nucleus) produced from photoionization of water molecules by solar radiation, and not photons from the Sun as thought earlier, are responsible for the degradation of water and carbon dioxide molecules released from the comet nucleus into its coma.<ref name="NASA-20150602"/><ref name="AA-20150602"/> Also, active pits, related to sinkhole collapses and possibly associated with outbursts are present on the comet.<ref name="NAT-20150702"/><ref name="AP-20150701"/>
Measurements by the COSAC and Ptolemy instruments on the ''Philae''{{'s}} lander revealed sixteen organic compounds, four of which were seen for the first time on a comet, including acetamide, acetone, methyl isocyanate and propionaldehyde.<ref name="wapo20150730"/><ref name="esa20150730"/><ref name="SCI-20150731"/> Astrobiologists Chandra Wickramasinghe and Max Wallis stated that some of the physical features detected on the comet's surface by ''Rosetta'' and ''Philae'', such as its organic-rich crust, could be explained by the presence of extraterrestrial microorganisms.<ref name="TG-20150705"/><ref name="SN-20150706"/> ''Rosetta'' program scientists dismissed the claim as "pure speculation".<ref name="TT-20150706"/> Carbon-rich compounds are common in the Solar System. Neither ''Rosetta'' nor ''Philae'' is equipped to search for direct evidence of organisms.<ref name="TG-20150705"/> The only amino acid detected thus far on the comet is glycine, along with precursor molecules methylamine and ethylamine.<ref name="Altwegg 2016"/>
Solid organic compounds were also found in the dust particles emitted by the comet; the carbon in this organic material is bound in "very large macromolecular compounds", analogous to the insoluble organic matter in carbonaceous chondrite meteorites. Scientists think that the observed cometary carbonaceous solid matter could have the same origin as the meteoritic insoluble organic matter, but suffered less modification before or after being incorporated into the comet.<ref name="Fray 2016"/>
One of the most outstanding discoveries of the mission was the detection of large amounts of free molecular oxygen ({{chem2|O2}}) gas surrounding the comet. Solar system models suggest the molecular oxygen should have disappeared by the time 67P was created, about 4.6 billion years ago in a violent and hot process that would have caused the oxygen to react with hydrogen and form water.<ref name="Bieler 2015"/><ref name="Howel 2015"/> Molecular oxygen has never before been detected in cometary comas. ''In situ'' measurements indicate that the {{chem2|O2}}/{{chem2|H2O}} ratio is isotropic in the coma and does not change systematically with heliocentric distance, suggesting that primordial {{chem2|O2}} was incorporated into the nucleus during the comet's formation.<ref name="Bieler 2015"/> This interpretation was challenged by the discovery that {{chem2|O2}} may be produced on the surface of the comet in water molecule collisions with silicates and other oxygen-containing materials.<ref name="Yao 2017"/> Detection of molecular nitrogen ({{chem2|N2}}) in the comet suggests that its cometary grains formed in low-temperature conditions below {{cvt|30|K|C F|0}}.<ref name="Rubin2015"/>
On 3 July 2018, researchers hypothesized that molecular oxygen might not be made on the surface of comet 67P in sufficient quantity, thus deepening the mystery of its origin.<ref name="Heritier2018"/><ref name="imperial20180703"/>
=== Future missions === CAESAR was a proposed sample-return mission aimed at returning to 67P/Churyumov–Gerasimenko, capturing regolith from the surface, and returning it to Earth.<ref name="nasa20171220"/><ref name="nytimes20171219"/> This mission was competing in NASA's New Frontiers mission 4 selection process, and was one of two finalists in the program.<ref name="ibtimes20171220"/> In June 2019, it was passed over in favor of ''Dragonfly''.<ref name="nyt20190627"/><ref name="spnews20190627"/>
== Gallery == <gallery mode="packed" heights="130px"> File:67PNucleus.jpg|A reconstruction of the nucleus's shape based on ''Hubble'' observations in 2003 File:VLT Tracks Rosetta's Comet.jpg|As seen by the Very Large Telescope on 11 August 2014<ref name="esobs20140908"/> File:Comet_67P on 22 August 2014 NavCam.jpg|As seen by ''Rosetta'' on 22 August 2014 File:Comet 67P on 14 September 2014 NavCam mosaic.jpg|As seen by ''Rosetta'' on 14 September 2014 File:67P-C-G - March 28 2015 (32370930490).jpg|As seen by ''Rosetta'' on 28 March 2015 File:67P-C-G - May 2 2015 (32730086746).jpg|As seen by ''Rosetta'' on 2 May 2015 File:Comet on 7 July 2015 NavCam.jpg|As seen by ''Rosetta'' on 7 July 2015 File:Cliffs of Comet 67P.jpg|Image showing ragged cliffs, 10 December 2014 File:Phosphorus-bearing molecules found in a star-forming region and comet 67P.tif| Phosphorus-bearing molecules found in a star-forming region and comet 67P<ref>{{cite web |title=Astronomers Reveal Interstellar Thread of One of Life's Building Blocks - ALMA and Rosetta map the journey of phosphorus |url=https://www.eso.org/public/news/eso2001/ |website=eso.org |access-date=16 January 2020 |language=en}}</ref> File:67P Churyumov-Gerasimenko - Rosetta (32755885495).png|Comet 67P/Churyumov–Gerasimenko in enhanced colour, as imaged by ESA's Rosetta spacecraft in 2015 </gallery>
== See also == * List of comets visited by spacecraft * {{Section link|List of numbered comets|67P}}
== Notes == {{notelist}}
== References == {{Reflist|refs= <ref name="jpldata">{{cite web |url=https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=67P&view=OPC |title=JPL Small-Body Database Browser: 67P/Churyumov-Gerasimenko |publisher=NASA/Jet Propulsion Laboratory |archive-url=https://archive.today/20121213144036/http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=67P;cad=1%23cad |archive-date=2012-12-13 |url-status=live |access-date=17 July 2023}}</ref>
<ref name="AP-20150813">{{cite news |title=Comet where spacecraft landed makes closest approach to sun |url=http://apnews.excite.com/article/20150813/sci--comet_mission-8099ace127.html |date=13 August 2015 |work=AP News |archive-url=https://web.archive.org/web/20151208112517/http://apnews.excite.com/article/20150813/sci--comet_mission-8099ace127.html |archive-date=8 December 2015 |access-date=14 August 2015}}</ref>
<ref name="esa20150122">{{cite web |url=http://www.esa.int/spaceinimages/Images/2015/01/Comet_vital_statistics |title=Comet vital statistics |publisher=European Space Agency |date=22 January 2015 |access-date=24 January 2015}}</ref>
<ref name="mass density 2016">{{cite journal |title=A homogeneous nucleus for comet 67P/Churyumov–Gerasimenko from its gravity field |journal=Nature |date=4 February 2016 |last1=Pätzold |first1=M. |last2=Andert |first2=T. |name-list-style=amp |volume=530 |issue=7588 |pages=63–65 |doi=10.1038/nature16535 |pmid=26842054 |display-authors=etal |bibcode=2016Natur.530...63P|s2cid=4470894 }}</ref>
<ref name="Lakdawalla1118">{{cite web |url=http://www.planetary.org/blogs/emily-lakdawalla/2015/dps15-1118-rosetta.html |title=DPS 2015: A little science from Rosetta, beyond perihelion |publisher=The Planetary Society |first=Emily |last=Lakdawalla |date=19 November 2015 |access-date=8 December 2015}}</ref>
<ref name="mpg20140121">{{cite news |url=http://www.mpg.de/8323012/expedition_primeval_matter |title=Expedition to primeval matter |publisher=Max-Planck-Gesellschaft |first=Thorsten |last=Dambeck |date=21 January 2014 |access-date=19 September 2014}}</ref>
<ref name="Mottola2014">{{cite journal |title=The rotation state of 67P/Churyumov-Gerasimenko from approach observations with the OSIRIS cameras on Rosetta |journal=Astronomy & Astrophysics |first1=S. |last1=Mottola |first2=S. |last2=Lowry |first3=C. |last3=Snodgrass |first4=P. L. |last4=Lamy |first5=I. |last5=Toth |first6=A. |last6=Rozek |first7=H. |last7=Sierks |first8=M. F. |last8=A'Hearn |first9=F. |last9=Angrilli |first10=C. |last10=Barbieri |first11=M. A. |last11=Barucci |first12=J.-L. |last12=Bertaux |first13=G. |last13=Cremonese |first14=V. |last14=Da Deppo |first15=B. |last15=Davidsson |first16=M. |last16=De Cecco |first17=S. |last17=Debei |first18=S. |last18=Fornasier |first19=M. |last19=Fulle |first20=O. |last20=Groussin |first21=P. |last21=Gutiérrez |first22=S. F. |last22=Hviid |first23=W. |last23=Ip |first24=L. |last24=Jorda |first25=H. U. |last25=Keller |first26=J. |last26=Knollenberg |first27=D. |last27=Koschny |first28=R. |last28=Kramm |first29=E. |last29=Kührt |first30=M. |last30=Küppers |first31=L. |last31=Lara |first32=M. |last32=Lazzarin |first33=J. J. |last33=Lopez Moreno |first34=F. |last34=Marzari |first35=H. |last35=Michalik |first36=G. |last36=Naletto |first37=H. |last37=Rickman |first38=R. |last38=Rodrigo |first39=L. |last39=Sabau |first40=N. |last40=Thomas |first41=K.-P. |last41=Wenzel |first42=J. |last42=Agarwal |first43=I. |last43=Bertini |first44=F. |last44=Ferri |first45=C. |last45=Güttler |first46=S. |last46=Magrin |first47=N. |last47=Oklay |first48=C. |last48=Tubiana |first49=J.-B. |last49=Vincent |volume=569 |at=L2 |date=September 2014 |doi=10.1051/0004-6361/201424590 |bibcode=2014A&A...569L...2M|doi-access=free |hdl=11577/3031099 |hdl-access=free }}</ref>
<ref name=yfernandez>{{cite web |title=List of Jupiter-Family and Halley-Family Comets |url=http://www.physics.ucf.edu/~yfernandez/cometlist.html |date=28 July 2015 |publisher=University of Central Florida: Physics |access-date=6 September 2015}}</ref>
<ref name="AP-20141210-SB">{{cite news |url=https://apnews.com/ace876c932724f628c269ba9eadfe867 |title=The mystery of where Earth's water came from deepens |work=Associated Press |first=Seth |last=Borenstein |date=10 December 2014 |access-date=15 August 2020}}</ref>
<ref name="ESA-faq">{{cite web |url=http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions |title=Rosetta's Frequently Asked Questions |publisher=European Space Agency |year=2014 |access-date=12 November 2014}}</ref>
<ref name="67P_size">{{cite web |url=https://www.youtube.com/watch?v=F9h1CTODg1k |title=Bigger than you think! Comet 67P compared to cities. HD |publisher=YouTube |date=12 November 2014 |access-date=17 November 2014}}</ref>
<ref name="Yoshida">{{cite web |url=http://www.aerith.net/comet/catalog/0067P/index.html |title=67P/Churyumov-Gerasimenko |publisher=Aerith.net |first=Seiichi |last=Yoshida |date=30 December 2010 |access-date=9 February 2012}}</ref>
<ref name="MPC">{{cite web |url=http://www.minorplanetcenter.net/db_search/show_object?object_id=67P |title=67P/Churyumov-Gerasimenko |publisher=Minor Planet Center |access-date=26 February 2017}}</ref>
<ref name="Kinoshita">{{cite web |url=http://jcometobs.web.fc2.com/pcmtn/0067p.htm |title=67P/Churyumov-Gerasimenko past, present and future orbital elements |work=Comet Orbit |first=Kazuo |last=Kinoshita |date=1 December 2018 |archive-url=https://web.archive.org/web/20110724055135/http://jcometobs.web.fc2.com/pcmtn/0067p.htm |archive-date=2011-07-24 |url-status=live |access-date=17 July 2023}}</ref>
<ref name="Krolikowska2003">{{cite journal |title=67P/Churyumov–Gerasimenko – potential target for the Rosetta mission |journal=Acta Astronomica |first=Malgorzata |last=Krolikowska |volume=53 |pages=195–209 |year=2003 |arxiv=astro-ph/0309130 |bibcode=2003AcA....53..195K}}</ref>
<ref name="NASA-201401017">{{cite news |url=http://www.jpl.nasa.gov/news/news.php?release=2014-015 |title=Rosetta: To Chase a Comet |publisher=NASA |first1=D. C. |last1=Agle |first2=Jia-Rui |last2=Cook |first3=Dwayne |last3=Brown |first4=Markus |last4=Bauer |date=17 January 2014 |access-date=18 January 2014 |id=Release 2014-015}}</ref>
<ref name="NYT-20140805">{{cite news |url=https://www.nytimes.com/2014/08/06/science/space/rosetta-spacecraft-set-for-unprecedented-close-study-of-a-comet.html |title=Rosetta Spacecraft Set for Unprecedented Close Study of a Comet |work=The New York Times |first=Kenneth |last=Chang |date=5 August 2014 |access-date=5 August 2014}}</ref>
<ref name="Fischer2014-08-06">{{cite web |url=http://www.planetary.org/blogs/guest-blogs/2014/0806-fischer-rendezvous-with-a-crazy-world.html |title=Rendezvous with a crazy world |publisher=The Planetary Society |first=D. |last=Fischer |date=6 August 2014 |access-date=6 August 2014 |archive-url=https://web.archive.org/web/20140806210446/http://www.planetary.org/blogs/guest-blogs/2014/0806-fischer-rendezvous-with-a-crazy-world.html |archive-date=6 August 2014 |url-status=live}}</ref>
<ref name="Bauer2014">{{cite web |url=http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_arrives_at_comet_destination |title=Rosetta Arrives at Comet Destination |publisher=European Space Agency |first=Markus |last=Bauer |date=6 August 2014 |access-date=6 August 2014 |archive-url=https://web.archive.org/web/20140806111419/http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_arrives_at_comet_destination |archive-date=6 August 2014 |url-status=live}}</ref>
<ref name="esa20140910">{{cite web |url=http://blogs.esa.int/rosetta/2014/09/10/down-down-we-go-to-29-km-or-lower/ |title=Down, down we go to 29 km – or lower? |publisher=European Space Agency |first=Daniel |last=Scuka |date=10 September 2014 |access-date=20 September 2014}}</ref>
<ref name="NASA-20141112-DCA">{{cite web |url=http://www.jpl.nasa.gov/news/news.php?release=2014-394 |title=Rosetta's 'Philae' Makes Historic First Landing on a Comet |publisher=NASA |first1=D. C. |last1=Agle |first2=Guy |last2=Webster |first3=Dwayne |last3=Brown |first4=Markus |last4=Bauer |date=12 November 2014 |access-date=13 November 2014}}</ref>
<ref name="NYT-20141112-KC">{{cite news |url=https://www.nytimes.com/2014/11/13/science/space/european-space-agencys-spacecraft-lands-on-comets-surface.html |title=European Space Agency's Spacecraft Lands on Comet's Surface |work=The New York Times |first=Kenneth |last=Chang |date=12 November 2014 |access-date=12 November 2014}}</ref>
<ref name=bbcland>{{cite news |url=https://www.bbc.com/news/science-environment-30026398 |title=Probe makes historic comet landing |work=BBC News |date=12 November 2014 |access-date=12 November 2014}}</ref>
<ref name="newsci20160930">{{cite news |url=https://www.newscientist.com/article/2107585-rosetta-lands-on-67p-in-grand-finale-to-two-year-comet-mission/ |title=Rosetta lands on 67P in grand finale to two year comet mission |work=New Scientist |first=Jacob |last=Aron |date=30 September 2016 |access-date=1 October 2016}}</ref>
<ref name="space20160930">{{cite news |url=http://www.space.com/34254-rosetta-crash-lands-on-comet-mission-ends.html |title=Goodbye, Rosetta! Spacecraft Crash-Lands on Comet in Epic Mission Finale |work=Space.com |first=Megan |last=Gannon |date=30 September 2016 |access-date=1 October 2016}}</ref>
<ref name="iau61">{{cite web |url=http://www.iau.org/administration/membership/individual/61/ |title=Klim Ivanovich Churyumov |publisher=International Astronomical Union |access-date=8 August 2014}}</ref>
<ref name="Kronk">{{cite book |chapter-url=https://books.google.com/books?id=qV4Q49x8PTsC&pg=PA241 |chapter=67P/1969 R1 (Churyumov-Gerasimenko) |title=Cometography: A Catalog of Comets; Volume 5: 1960–1982 |publisher=Cambridge University Press |first1=Gary W. |last1=Kronk |first2=Maik |last2=Meyer |name-list-style=amp |pages=241–245 |year=2010 |isbn=978-0-521-87226-3}}</ref>
<ref name="Bertaux2015">{{cite journal |url=https://hal-insu.archives-ouvertes.fr/insu-01175722/document |title=Estimate of the erosion rate from H2O mass-loss measurements from SWAN/SOHO in previous perihelions of comet 67P/Churyumov-Gerasimenko and connection with observed rotation rate variations |journal=Astronomy & Astrophysics |first=Jean-Loup |last=Bertaux |volume=583 |at=A38 |date=November 2015 |doi=10.1051/0004-6361/201525992 |bibcode=2015A&A...583A..38B|doi-access=free }}</ref>
<ref name="natgeo20150928">{{cite news |url=http://news.nationalgeographic.com/2015/09/150928-comet-67p-rubber-duck-shape-space-science/ |archive-url=https://web.archive.org/web/20150930220114/http://news.nationalgeographic.com/2015/09/150928-comet-67p-rubber-duck-shape-space-science/ |url-status=dead |archive-date=30 September 2015 |title=Why Comet 67P Looks Like a Rubber Ducky |work=National Geographic |first=Michael D. |last=Lemonick |date=28 September 2015 |access-date=29 September 2015}}</ref>
<ref name="Massironi2015">{{cite journal |title=Two independent and primitive envelopes of the bilobate nucleus of comet 67P |journal=Nature |first1=Matteo |last1=Massironi |first2=Emanuele |last2=Simioni |first3=Francesco |last3=Marzari |first4=Gabriele |last4=Cremonese |first5=Lorenza |last5=Giacomini |volume=526 |issue=7573 |pages=402–405 |date=28 September 2015 |doi=10.1038/nature15511 |bibcode=2015Natur.526..402M |pmid=26416730|s2cid=4463714 }}</ref>
<ref name="ElMaarry2015">{{cite journal |title=Regional surface morphology of comet 67P/Churyumov-Gerasimenko from Rosetta/OSIRIS images |journal=Astronomy & Astrophysics |first1=M. R. |last1=El-Maarry |first2=N. |last2=Thomas |first3=L. |last3=Giacomini |volume=583 |at=A26 |date=November 2015 |doi=10.1051/0004-6361/201525723 |bibcode=2015A&A...583A..26E |url=https://boris.unibe.ch/81654/8/RegionalMorpholy67P_ElMaarry_RefereeFormat.pdf|doi-access=free }}</ref>
<ref name="space20150719">{{cite news |url=http://www.space.com/29980-rosetta-comet-67p-egyptian-gods-names.html |title=Gods Among the Stars: Why Egyptian Names Grace Comet 67P |work=Space.com |first=Calla |last=Cofield |date=19 July 2015 |access-date=12 April 2016}}</ref>
<ref name="ElMaarry2016">{{cite journal |title=Regional surface morphology of comet 67P/Churyumov-Gerasimenko from Rosetta/OSIRIS images: The southern hemisphere |journal=Astronomy & Astrophysics |first1=M. R. |last1=El-Maarry |first2=N. |last2=Thomas |first3=A. |last3=Gracia-Berná |volume=593 |at=A110 |date=September 2016 |doi=10.1051/0004-6361/201628634 |bibcode=2016A&A...593A.110E|doi-access=free |hdl=10261/146576 |hdl-access=free }}</ref>
<ref name="esa20160224">{{cite web |url=http://blogs.esa.int/rosetta/2016/02/24/getting-to-know-the-comets-southern-hemisphere/ |title=Getting to know the comet's southern hemisphere |publisher=European Space Agency |first=Emily |last=Baldwin |date=24 February 2016 |access-date=3 May 2017}}</ref>
<ref name="esablog20150928">{{cite web |url=http://blogs.esa.int/rosetta/2015/09/28/rosetta-science-working-team-dedication-to-deceased-colleagues/ |title=Rosetta Science Working Team dedication to deceased colleagues |publisher=European Space Agency |first=Matt |last=Taylor |date=28 September 2015 |access-date=2 October 2015}}</ref>
<ref name="ElMaarry2017">{{cite journal |title=Surface changes on comet 67P/Churyumov-Gerasimenko suggest a more active past |journal=Science |first1=M. Ramy |last1=El-Maarry |first2=O. |last2=Groussin |first3=N. |last3=Thomas |volume=355 |issue=6332 |pages=1392–1395 |date=March 2017 |doi=10.1126/science.aak9384 |pmid=28325842 |bibcode=2017Sci...355.1392E |s2cid=9579837 |url=http://eprints.bbk.ac.uk/24696/1/24696.pdf}}</ref>
<ref name="esa20170321">{{cite web |url=http://www.esa.int/Our_Activities/Space_Science/Rosetta/Before_and_after_unique_changes_spotted_on_Rosetta_s_comet |title=Before and after: Unique changes spotted on Rosetta's comet |publisher=European Space Agency |first1=Markus |last1=Bauer |first2=M. Ramy |last2=El-Maarry |first3=Matt |last3=Taylor |date=21 March 2017 |access-date=2 May 2017}}</ref>
<ref name="nasa20170321">{{cite web |url=https://www.nasa.gov/feature/jpl/the-many-faces-of-rosetta-s-comet-67p |title=The Many Faces of Rosetta's Comet 67P |publisher=NASA |first1=D. C. |last1=Agle |first2=Dwayne |last2=Brown |first3=Laurie |last3=Cantillo |first4=Markus |last4=Bauer |date=21 March 2017 |access-date=2 May 2017}}</ref>
<ref name="Groussin2015">{{cite journal |title=Temporal morphological changes in the Imhotep region of comet 67P/Churyumov-Gerasimenko |journal=Astronomy & Astrophysics |first1=O. |last1=Groussin |first2=H. |last2=Sierks |first3=C. |last3=Barbieri |volume=583 |at=A36 |date=November 2015 |doi=10.1051/0004-6361/201527020 |bibcode=2015A&A...583A..36G |arxiv=1509.02794|s2cid=54177318 }}</ref>
<ref name="esa20150918">{{cite web |url=http://blogs.esa.int/rosetta/2015/09/18/comet-surface-changes-before-rosettas-eyes/ |title=Comet surface changes before Rosetta's eyes |publisher=European Space Agency |first=Claudia |last=Mignone |date=18 September 2015 |access-date=3 May 2017}}</ref>
<ref name="Pajola2017">{{cite journal |title=The pristine interior of comet 67P revealed by the combined Aswan outburst and cliff collapse |journal=Nature Astronomy |first1=Maurizio |last1=Pajola |first2=S. |last2=Höfner |first3=J. B. |last3=Vincent |first4=N. |last4=Oklay |first5=F. |last5=Scholten |volume=1 |issue=5 |at=0092 |date=21 March 2017 |doi=10.1038/s41550-017-0092 |bibcode=2017NatAs...1E..92P |s2cid=46870552 |url=http://kar.kent.ac.uk/61744/1/Pajola_manuscript_SCL-merged.pdf}}</ref>
<ref name="wapo20170321">{{cite news |url=https://www.washingtonpost.com/news/speaking-of-science/wp/2017/03/21/scientists-captured-incredible-photographic-proof-of-a-landslide-on-a-comet/ |title=Scientists captured incredible photographic proof of a landslide on a comet |newspaper=The Washington Post |first=Sarah |last=Kaplan |date=21 March 2017 |access-date=21 March 2017}}</ref>
<ref name="MPC-emp">{{cite web |url=http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=c&o=0067P |title=Elements and Ephemeris for 67P/Churyumov-Gerasimenko |publisher=Minor Planet Center |access-date=9 August 2014 |url-status=dead |archive-url=https://web.archive.org/web/20141104155055/http://scully.cfa.harvard.edu/cgi-bin/returnprepeph.cgi?d=c&o=0067P |archive-date=4 November 2014}}</ref>
<ref name="STScI-2003-26">{{cite news |url=http://hubblesite.org/newscenter/archive/releases/2003/26/text/ |title=Hubble Assists Rosetta Comet Mission |publisher=HubbleSite.org |first1=Michael |last1=Buckley |first2=Ray |last2=Villard |first3=Lars |last3=Christensen |date=5 September 2003}}</ref>
<ref name="blog140623">{{cite web |url=http://blogs.esa.int/rosetta/2014/06/23/first-detection-of-water-from-67pc-g/ |title=First Detection of Water from 67P/C-G |publisher=European Space Agency |first=Emily |last=Baldwin |date=23 June 2014 |access-date=23 June 2014}} [https://twitter.com/SungrazerComets/status/481070906153123841 Sungrazer Comets] at Twitter.com.</ref>
<ref name="NASA-20140630">{{cite web |url=http://www.jpl.nasa.gov/news/news.php?release=2014-212 |title=Rosetta's Comet Target 'Releases' Plentiful Water |publisher=NASA |first1=D. C. |last1=Agle |first2=Dwayne |last2=Brown |first3=Markus |last3=Bauer |date=30 June 2014 |access-date=30 June 2014}}</ref>
<ref name="astronomy20140717">{{cite news |url=http://www.astronomy.com/news/2014/07/the-twofold-comet-comet-67pchuryumov-gerasimenko |title=The twofold comet: Comet 67P/Churyumov-Gerasimenko |work=Astronomy.com |date=17 July 2014 |access-date=18 July 2014}}</ref>
<ref name="skytel20140717">{{cite news |url=http://www.skyandtelescope.com/astronomy-news/rubber-ducky-space-07172014/ |title=Rosetta's Comet has a Split Personality |work=Sky & Telescope |first=Maria |last=Temming |date=17 July 2014 |access-date=18 July 2014}}</ref>
<ref name="esa20150928">{{cite web |url=http://sci.esa.int/rosetta/56543-how-rosetta-s-comet-got-its-shape/ |title=How Rosetta's comet got its shape |publisher=European Space Agency |first1=Markus |last1=Bauer |first2=Matteo |last2=Massironi |first3=Holger |last3=Sierks |first4=Matt |last4=Taylor |date=28 September 2015 |access-date=29 June 2019}}</ref>
<ref name="csm20140804">{{cite news |url=https://www.csmonitor.com/Science/2014/0804/Comet-chasing-Euro-probe-could-make-history-Wednesday |title=Comet-chasing Euro-probe could make history Wednesday |work=The Christian Science Monitor |first=Megan |last=Gannon |date=4 August 2014 |access-date=6 August 2014}}</ref>
<ref name="Lakdawalla2014-08-15">{{cite web |url=http://www.planetary.org/blogs/emily-lakdawalla/2014/08150814-finding-my-way-around-cg.html |title=Finding my way around comet Churyumov-Gerasimenko |publisher=The Planetary Society |first=Emily |last=Lakdawalla |author-link=Emily Lakdawalla |date=15 August 2014 |access-date=15 August 2014 |archive-url=https://web.archive.org/web/20140815234826/http://www.planetary.org/blogs/emily-lakdawalla/2014/08150814-finding-my-way-around-cg.html |archive-date=15 August 2014 |url-status=live}}</ref>
<ref name="NYT-20141110-KC">{{cite news |url=https://www.nytimes.com/2014/11/11/science/space/philae-lander-nears-a-cosmic-touchdown.html |title=Philae Lander Nears a Cosmic Touchdown |work=The New York Times |first=Kenneth |last=Chang |date=10 November 2014 |access-date=11 November 2014}}</ref>
<ref name="bbcnews20141104">{{cite news |url=https://www.bbc.com/news/science-environment-29902456 |title=Rosetta comet mission: Landing site named 'Agilkia' |work=BBC News |first=Jonathan |last=Amos |date=4 November 2014 |access-date=9 November 2014}}</ref>
<ref name="Hilchenbach2004">{{cite conference |url=http://www.simpack.com/fileadmin/simpack/doc/usermeeting04/um04_maxplanck_hilch.pdf |title=Simulation of the Landing of Rosetta Philae on Comet 67P/Churyumov-Gerasimenko |conference=SIMPACK User Meeting. 9–10 November 2004. Wartburg/Eisenach, Germany. |first=M. |last=Hilchenbach |page=25 |year=2004 |access-date=6 August 2014 |archive-url=https://web.archive.org/web/20141126221921/http://www.simpack.com/fileadmin/simpack/doc/usermeeting04/um04_maxplanck_hilch.pdf |archive-date=26 November 2014 |url-status=dead }}</ref>
<ref name="cnn20141113">{{cite news |url=http://www.cnn.com/2014/11/12/world/comet-landing-countdown/index.html |title=Space probe scores a 310-million-mile bull's-eye with comet landing |publisher=CNN |first=Ralph |last=Ellis |date=13 November 2014 |access-date=13 November 2014 |quote=Comet 67P has a very weak gravity, so anchoring harpoons were designed to shoot into the comet to fix the spacecraft to the surface.}}</ref>
<ref name="register20141112">{{cite news |url=https://www.theregister.co.uk/2014/11/12/philae_comet_landing_bounce_speculation/ |title=Bouncy bouncy: Comet probot Philae may have landed twice |work=The Register |first=Brid-Aine |last=Parnell |date=12 November 2014 |access-date=13 November 2014 |quote=Philae's flywheel was part of its landing gear and stopped the craft from rotating while it was operational, but it was switched off once the probot indicated it had touched down.}}</ref>
<ref name="discovery20141112">{{cite news |url=http://news.discovery.com/space/rosettas-philae-lander-grabs-onto-comet-and-lands-141112.htm |title=Rosetta's Lander Grabs Onto Comet and Lands |work=Discovery News |first=Ian |last=O'Neill |date=12 November 2014 |access-date=13 November 2014 |quote=As there was a real risk of the lander bouncing off the comet, harpoons, landing leg ice screws and thrusters needed to work in concert to ensure Philae stayed in place. |archive-date=15 November 2014 |archive-url=https://web.archive.org/web/20141115010539/http://news.discovery.com/space/rosettas-philae-lander-grabs-onto-comet-and-lands-141112.htm |url-status=dead }}</ref>
<ref name="NASA-20141113-DCA">{{cite web |url=http://www.jpl.nasa.gov/news/news.php?release=2014-396 |title=Rosetta's Comet Lander Landed Three Times |publisher=NASA |first1=D. C. |last1=Agle |first2=Dwayne |last2=Brown |first3=Markus |last3=Bauer |date=13 November 2014 |access-date=13 November 2014}}</ref>
<ref name="skytel20141112">{{cite news |url=http://www.skyandtelescope.com/astronomy-news/philae-lands-three-times-111220143/ |title=Philae Lands on Its Comet – Three Times! |work=Sky & Telescope |first=Kelly |last=Beatty |date=12 November 2014 |access-date=26 November 2014}}</ref>
<ref name="nature20150614">{{cite news |url=http://www.nature.com/news/philae-comet-lander-wakes-up-and-phones-home-1.17756 |title=Philae comet lander wakes up and phones home |journal=Nature |first1=Celeste |last1=Biever |first2=Elizabeth |last2=Gibney |name-list-style=amp |date=14 June 2015 |access-date=14 June 2015 |doi=10.1038/nature.2015.17756}}</ref>
<ref name="skytel20160905">{{cite news |url=http://www.skyandtelescope.com/astronomy-news/esa-locates-philae-lander/ |title=Finally, ESA Locates Comet Lander Philae |work=Sky & Telescope |first=Kelly |last=Beatty |date=5 September 2016 |access-date=10 September 2016}}</ref>
<ref name="NASA-20141210-DCA">{{cite web |url=http://www.jpl.nasa.gov/news/news.php?release=2014-423 |title=Rosetta Instrument Reignites Debate on Earth's Oceans |publisher=NASA |first1=D. C. |last1=Agle |first2=Markus |last2=Bauer |name-list-style=amp |date=10 December 2014 |access-date=10 December 2014}}</ref>
<ref name="NYT-20141210-KC">{{cite news |url=https://www.nytimes.com/2014/12/11/science/rosetta-mission-data-rules-out-comets-as-a-source-for-earths-water.html |title=Comet Data Clears Up Debate on Earth's Water |work=The New York Times |first=Kenneth |last=Chang |date=10 December 2014 |access-date=10 December 2014}}</ref>
<ref name="NASA-20150122">{{cite web |last1=Agle |first1=D. C. |last2=Brown |first2=Dwayne |last3=Bauer |first3=Markus |url=http://www.jpl.nasa.gov/news/news.php?release=2015-029 |title=Rosetta Comet 'Pouring' More Water Into Space |publisher=NASA |date=22 January 2015 |access-date=22 January 2015}}</ref>
<ref name="SCI-20150123">{{cite journal |url=https://www.science.org/toc/science/347/6220 |title=Catching a Comet |series=Special Issue. |journal=Science |volume=347 |issue=6220 |date=23 January 2015 |access-date=23 January 2015}}</ref>
<ref name="esa20141218">{{cite web |url=http://blogs.esa.int/rosetta/2014/11/18/philae-settles-in-dust-covered-ice/ |title=Philae settles in dust-covered ice |publisher=European Space Agency |first=Emily |last=Baldwin |date=18 November 2014 |access-date=18 December 2014}}</ref>
<ref name="esa20150414">{{cite news |url=http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_and_Philae_find_comet_not_magnetised |title=Rosetta and Philae Find Comet Not Magnetised |publisher=European Space Agency |first=Markus |last=Bauer |date=14 April 2015 |access-date=14 April 2015}}</ref>
<ref name="nature20150414">{{cite journal |title=Rosetta's comet has no magnetic field |journal=Nature |first=Quirin |last=Schiermeier |date=14 April 2015 |doi=10.1038/nature.2015.17327|s2cid=123964604 }}</ref>
<ref name="NASA-20150602">{{cite news |url=http://www.jpl.nasa.gov/news/news.php?feature=4609 |title=NASA Instrument on Rosetta Makes Comet Atmosphere Discovery |publisher=NASA |last1=Agle |first1=D. C. |last2=Brown |first2=Dwayne |last3=Fohn |first3=Joe |last4=Bauer |first4=Markus |date=2 June 2015 |access-date=2 June 2015}}</ref>
<ref name="AA-20150602">{{cite journal |url=http://www.aanda.org/articles/aa/pdf/forth/aa25925-15.pdf |title=Measurements of the near-nucleus coma of comet 67P/Churyumov-Gerasimenko with the Alice far-ultraviolet spectrograph on Rosetta |journal=Astronomy & Astrophysics |last1=Feldman |first1=Paul D. |last2=A'Hearn |first2=Michael F. |last3=Bertaux |first3=Jean-Loup |last4=Feaga |first4=Lori M. |last5=Parker |first5=Joel Wm. |last6=Schindhelm |first6=Eric |last7=Steiffl |first7=Andrew J. |last8=Stern |first8=S. Alan |last9=Weaver |first9=Harold A. |last10=Sierks |first10=Holger |last11=Vincent |first11=Jean-Baptiste |date=2 June 2015 |doi=10.1051/0004-6361/201525925 |arxiv=1506.01203 |bibcode=2015A&A...583A...8F |volume=583 |pages=A8|s2cid=119104807 }}</ref>
<ref name="NAT-20150702">{{cite journal |title=Large heterogeneities in comet 67P as revealed by active pits from sinkhole collapse |journal=Nature |first=Jean-Baptiste |last=Vincent |display-authors=etal |volume=523 |issue=7558 |pages=63–66 |date=2 July 2015 |doi=10.1038/nature14564 |bibcode=2015Natur.523...63V |pmid=26135448|s2cid=2993705 |url=https://hal-insu.archives-ouvertes.fr/insu-01176031/file/JBV2015.pdf }}</ref>
<ref name="AP-20150701">{{cite news |url=http://apnews.excite.com/article/20150701/us-sci--comet_sinkholes-11254d29fb.html |title=It's the pits: Comet appears to have sinkholes, study says |agency=Associated Press |last=Ritter |first=Malcolm |date=1 July 2015 |archive-url=https://web.archive.org/web/20150703035631/http://apnews.excite.com/article/20150701/us-sci--comet_sinkholes-11254d29fb.html |archive-date=3 July 2015 |access-date=2 July 2015}}</ref>
<ref name="wapo20150730">{{cite news |url=https://www.washingtonpost.com/world/philae-probe-finds-evidence-that-comets-can-be-cosmic-labs/2015/07/30/63a2fc0e-36e5-11e5-ab7b-6416d97c73c2_story.html |title=Philae probe finds evidence that comets can be cosmic labs |newspaper=The Washington Post |agency=Associated Press |first=Frank |last=Jordans |date=30 July 2015 |access-date=30 July 2015}}</ref>
<ref name="esa20150730">{{cite web |url=http://www.esa.int/Our_Activities/Space_Science/Rosetta/Science_on_the_surface_of_a_comet |title=Science on the Surface of a Comet |publisher=European Space Agency |date=30 July 2015 |access-date=30 July 2015}}</ref>
<ref name="SCI-20150731">{{cite journal |last1=Bibring |first1=J.-P. |last2=Taylor |first2=M. G. G. T. |last3=Alexander |first3=C. |last4=Auster |first4=U. |last5=Biele |first5=J. |last6=Finzi |first6=A. Ercoli |last7=Goesmann |first7=F. |last8=Klingehoefer |first8=G. |last9=Kofman |first9=W. |last10=Mottola |first10=S. |last11=Seidenstiker |first11=K. J. |last12=Spohn |first12=T. |last13=Wright |first13=I. |title=Philae's First Days on the Comet – Introduction to Special Issue |date=31 July 2015 |journal=Science |volume=349 |issue=6247 |page=493 |doi=10.1126/science.aac5116 |bibcode=2015Sci...349..493B |pmid=26228139|doi-access=free }}</ref>
<ref name="TG-20150705">{{cite news |url=https://www.theguardian.com/science/2015/jul/06/philae-comet-could-be-home-to-alien-life-say-top-scientists |title=Philae comet could be home to alien life, say scientists |work=The Guardian |first=Rebecca |last=Ratcliffe |date=5 July 2015 |access-date=6 July 2015}}</ref>
<ref name="SN-20150706">{{cite news |title=Alien Life On Philae Comet, Scientists Say |url=http://news.sky.com/story/1514080/alien-life-on-philae-comet-scientists-say |work=Sky News |date=6 July 2015 |access-date=6 July 2015}}</ref>
<ref name="TT-20150706">{{cite news |url=https://www.telegraph.co.uk/news/science/space/11720871/Alien-life-unlikely-on-Rosetta-comet-say-mission-scientists.html |archive-url=https://ghostarchive.org/archive/20220112/https://www.telegraph.co.uk/news/science/space/11720871/Alien-life-unlikely-on-Rosetta-comet-say-mission-scientists.html |archive-date=12 January 2022 |url-access=subscription |url-status=live |title=Alien life 'unlikely' on Rosetta comet, say mission scientists |work=The Daily Telegraph |first=Sarah |last=Knapton |date=6 July 2015 |access-date=6 July 2015}}{{cbignore}}</ref>
<ref name="Altwegg 2016">{{cite journal |title=Prebiotic chemicals—amino acid and phosphorus—in the coma of comet 67P/Churyumov-Gerasimenko |journal=Science Advances |last1=Altwegg |first1=Kathrin|author1-link=Kathrin Altwegg |last2=Balsiger |first2=Hans |last3=Bar-Nun |first3=Akiva |last4=Berthelier |first4=Jean-Jacques |last5=Bieler |first5=Andre |volume=2 |issue=5 |at=e1600285 |date=27 May 2016 |doi=10.1126/sciadv.1600285 |pmid=27386550 |pmc=4928965 |bibcode=2016SciA....2E0285A}}</ref>
<ref name="Fray 2016">{{cite journal |title=High-molecular-weight organic matter in the particles of comet 67P/Churyumov–Gerasimenko |journal=Nature |last1=Fray |first1=Nicolas |last2=Bardyn |first2=Anaïs |last3=Cottin |first3=Hervé |last4=Altwegg |first4=Kathrin|author4-link=Kathrin Altwegg |last5=Baklouti |first5=Donia |date=7 September 2016 |doi=10.1038/nature19320 |pmid=27602514 |volume=538 |issue=7623 |pages=72–74 |bibcode=2016Natur.538...72F|s2cid=205250295 }}</ref>
<ref name="Bieler 2015">{{cite journal |title=Abundant molecular oxygen in the coma of comet 67P/Churyumov–Gerasimenko |journal=Nature |date=29 October 2015 |last=Bieler |first=A. |display-authors=etal |volume=526 |issue=7575 |pages=678–681 |doi=10.1038/nature15707 |pmid=26511578 |bibcode=2015Natur.526..678B |s2cid=205246191 |url=https://hal.archives-ouvertes.fr/hal-01346075/file/O2_letter_v4.pdf}}</ref>
<ref name="Howel 2015">{{cite news |last=Howell |first=Elizabeth |url=http://www.space.com/30961-modern-mystery-ancient-comet-spewing-oxygen.html?adbid=10153138402681466&adbpl=fb&adbpr=17610706465 |title=Modern Mystery: Ancient Comet Is Spewing Oxygen |work=Space.com |date=28 October 2015 |access-date=6 November 2015}}</ref>
<ref name="Yao 2017">{{cite journal |title=Dynamic molecular oxygen production in cometary comae |journal=Nature Communications |first1=Y. |last1=Yao |first2=K.P. |last2=Giapis |name-list-style=amp |volume=8 |article-number=15298 |date=8 May 2017 |doi=10.1038/ncomms15298 |pmid=28480881 |pmc=5424151 |bibcode=2017NatCo...815298Y}}</ref>
<ref name="Rubin2015">{{cite journal |title=Molecular nitrogen in comet 67P/Churyumov-Gerasimenko indicates a low formation temperature |journal=Science |first1=M. |last1=Rubin |first2=K. |last2=Altwegg|author2-link=Kathrin Altwegg |first3=H. |last3=Balsiger |first4=A. |last4=Bar-Nun |first5=J.-J. |last5=Berthelier |volume=348 |issue=6231 |pages=232–235 |date=April 2015 |doi=10.1126/science.aaa6100 |bibcode=2015Sci...348..232R |pmid=25791084 |url=https://hal.archives-ouvertes.fr/hal-01346031|doi-access=free }}</ref>
<ref name="Heritier2018">{{cite journal |title=On the origin of molecular oxygen in cometary comae |journal=Nature Communications |first1=K. L. |last1=Heritier |first2=K. |last2=Altwegg |author2-link=Kathrin Altwegg|first3=J.-J. |last3=Berthelier |first4=A. |last4=Beth |first5=C. M. |last5=Carr |first6=J. |last6=De Keyser |first7=A. I. |last7=Eriksson |first8=S. A. |last8=Fuselier |first9=M. |last9=Galand |first10=T. I. |last10=Gombosi |first11=P. |last11=Henri |first12=F. L. |last12=Johansson |first13=H. |last13=Nilsson |first14=M. |last14=Rubin |first15=C. |last15=Simon Wedlund |first16=M. G. G. T. |last16=Taylor |first17=E. |last17=Vigren |volume=9 |issue=1 |at=2580 |date=3 July 2018 |doi=10.1038/s41467-018-04972-5 |pmid=29968720 |pmc=6030164 |bibcode=2018NatCo...9.2580H}}</ref>
<ref name="imperial20180703">{{cite news |url=http://www.imperial.ac.uk/news/187056/molecular-oxygen-comets-atmosphere-created-surface/ |title=Molecular oxygen in comet's atmosphere not created on its surface |publisher=Imperial College London |first=Hayley |last=Dunning |date=3 July 2018 |access-date=4 July 2018}}</ref>
<ref name="nasa20171220">{{cite web |url=https://www.nasa.gov/press-release/nasa-invests-in-concept-development-for-missions-to-comet-saturn-moon-titan |title=NASA Invests in Concept Development for Missions to Comet, Saturn Moon Titan |publisher=NASA |first1=Dwayne |last1=Brown |first2=Laurie |last2=Cantillo |first3=Molly |last3=Porter |date=20 December 2017 |access-date=25 December 2017}}</ref>
<ref name="nytimes20171219">{{cite news |url=https://www.nytimes.com/2017/12/19/science/nasa-new-frontiers-finalists.html |title=Finalists in NASA's Spacecraft Sweepstakes: A Drone on Titan, and a Comet-Chaser |first=Kenneth |last=Chang |work=The New York Times |date=19 December 2017 |access-date=25 December 2017}}</ref>
<ref name="ibtimes20171220">{{cite news |url=http://www.ibtimes.com/nasas-new-frontier-mission-will-search-alien-life-or-reveal-solar-systems-history-2631073 |title=NASA's New Frontier Mission Will Search For Alien Life Or Reveal The Solar System's History |work=International Business Times |first=Elana |last=Glowatz |date=20 December 2017 |access-date=25 December 2017}}</ref>
<ref name="nyt20190627">{{cite news |url=https://www.nytimes.com/2019/06/27/science/nasa-titan-dragonfly-caesar.html |title=NASA Announces New Dragonfly Drone Mission to Explore Titan |work=The New York Times |first=David W. |last=Brown |date=27 June 2019 |access-date=29 June 2019}}</ref>
<ref name="spnews20190627">{{cite news |url=https://spacenews.com/nasa-selects-titan-drone-for-next-new-frontiers-mission/ |title=NASA selects Titan drone for next New Frontiers mission |work=SpaceNews |first=Jeff |last=Foust |date=27 June 2019 |access-date=29 June 2019}}</ref>
<ref name="esobs20140908">{{cite web |url=http://www.eso.org/public/images/potw1436a/ |title=VLT Tracks Rosetta's Comet |publisher=European Southern Observatory |date=8 September 2014 |access-date=8 September 2014}}</ref>
<ref name="Horizons2028">{{cite web |title=Horizons Batch for 67P/Churyumov-Gerasimenko (90000696) on 2028-Apr-09 |publisher=JPL Horizons |type=Perihelion occurs when rdot flips from negative to positive |url=https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27DES%3D67P%3BCAP%27&START_TIME=%272028-Apr-07%27&STOP_TIME=%272028-Apr-12%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27 |archive-url=https://web.archive.org/web/20220628005852/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%2790000695%27&START_TIME=%272028-Apr-07%27&STOP_TIME=%272028-Apr-12%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27 |archive-date=2022-06-28 |url-status=live |access-date=2023-07-06}} (JPL#K213/5 Soln.date: 2023-May-04) [https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%2767P%27 (Records)]</ref>
<ref name="Dunn">{{cite web |title=67P @ Gravity Simulator |publisher=Gravity Simulator |author=Tony Dunn |url=http://orbitsimulator.com/gravitySimulatorCloud/simulations/1689707182555_67P.html |access-date=2023-07-21}}</ref>
<ref name="Horizons2223">{{cite web |title=Horizons Batch for 67P/Churyumov-Gerasimenko (90000696) on 2223-Feb-06 |publisher=JPL Horizons |type=Perihelion occurs when rdot flips from negative to positive |url=https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=%27DES%3D67P%3BCAP%27&START_TIME=%272223-Feb-01%27&STOP_TIME=%272223-Feb-11%27&STEP_SIZE=%273%20hours%27&QUANTITIES=%2719%27 |access-date=2023-07-17}} (JPL#K213/5 Soln.date: 2023-May-04)</ref>
}} <!-- end of reflist-->
== Further reading == * {{cite journal |title=The dust trail of Comet 67P/Churyumov–Gerasimenko between 2004 and 2006 |journal=Icarus |first1=Jessica |last1=Agarwal |first2=Michael |last2=Müller |first3=William T. |last3=Reach |first4=Mark V. |last4=Sykes |first5=Hermann |last5=Boehnhardt |first6=Eberhard |last6=Grün |volume=207 |issue=2 |pages=992–1012 |date=June 2010 |bibcode=2010Icar..207..992A |doi=10.1016/j.icarus.2010.01.003 |arxiv=1001.3775|s2cid=118634953 }} * {{cite news |url=https://www.nytimes.com/interactive/2015/03/20/science/space/rosetta-comet-photos.html |title=Rosetta Is Tailing a Warming Comet |work=The New York Times |first=Jonathan |last=Corum |date=30 April 2015}}
== External links == {{sister project links|d=Q844672|c=category:67P/Churyumov-Gerasimenko|n=no|b=no|v=no|voy=no|s=no|wikt=no|q=no|species=no}} * {{JPL Small Body|id=1000012}} * [http://cometography.com/pcomets/067p.html 67P/Churyumov–Gerasimenko] at Cometography * [https://web.archive.org/web/20071111050433/http://www.iac.es/galeria/mrk/comets/67p/67p.htm 67P/Churyumov–Gerasimenko] by the Instituto de Astrofísica de Canarias * [http://blogs.esa.int/rosetta/2013/10/16/how-the-heck-do-you-pronounce-it-anyway/ 67P/Churyumov–Gerasimenko pronunciation guide] by ESA * [https://science.nasa.gov/science-news/science-at-nasa/2012/02feb_rosetta/ "Mission to Land on a Comet"] by NASA * {{APOD |date=6 November 2017|title=A Dust Jet from the Surface of the Comet 67P}} * [https://www.youtube.com/watch?v=MH5crMuuf_0 ''Rosetta''{{'s}} final images] on YouTube, by ESA * [https://imagearchives.esac.esa.int/index.php?/category/1 ''Rosetta'' complete image archive] by ESA * [https://rosetta-3dcomet.cnes.fr/ OSIRIS stereo views of 67P/Churyumov–Gerasimenko] by CNES * [https://www.nytimes.com/2014/11/13/science/space/european-space-agencys-spacecraft-lands-on-comets-surface.html#permid=13314862 Landing News and Comments] (''The New York Times''; 12 November 2014)
{{PeriodicComets Navigator|66P/du Toit|68P/Klemola}} {{Rosetta mission}} {{Comets}} {{2014 in space}} {{Portal bar|Astronomy|Stars|Spaceflight|Outer space|Solar System}} {{Authority control}}
{{DEFAULTSORT:Churyumov-Gerasimenko, 067P}} 19690920 Category:Comets visited by spacecraft Category:Contact binary (small Solar System body) Category:Periodic comets 0067 067P 067P Category:Rosetta mission 067P 067P 067P Category:Discoveries by Klim Churyumov Category:Discoveries by Svetlana Gerasimenko Category:Anubis Category:Bastet Category:Hathor Category:Cultural depictions of Imhotep Category:Khonsu