Editing Rosetta (spacecraft) (section)

=== Deep space manoeuvres ===
To achieve the required velocity to rendezvous with 67P, ''Rosetta'' used [[gravity assist]] manoeuvres to accelerate throughout the inner Solar System.<ref name="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 |access-date=24 May 2014}}</ref> The comet's orbit was known before ''Rosetta''{{'s}} launch, from ground-based measurements, to an accuracy of approximately {{convert|100|km|abbr=on}}. Information gathered by the onboard cameras beginning at a distance of {{convert|24|e6km|mi}} were processed at ESA's Operation Centre to refine the position of the comet in its orbit to a few kilometres.{{Citation needed|date=September 2016}}

The first [[Earth]] flyby was on 4 March 2005.<ref name="Montagnon2006" />

On 25 February 2007, the craft was scheduled for a low-altitude flyby of [[Mars]], to correct the trajectory. This was not without risk, as the estimated altitude of the flyby was a mere {{convert|250|km}}.<ref name="eoportal">{{cite web|url=https://directory.eoportal.org/web/eoportal/satellite-missions/r/rosetta |title=Rosetta Rendezvous Mission with Comet 67P/Churyumov-Gerasimenko |work=eoPortal |publisher=European Space Agency |access-date=1 October 2016}}</ref> During that encounter, the solar panels could not be used since the craft was in the planet's shadow, where it would not receive any solar light for 15 minutes, causing a dangerous shortage of power. The craft was therefore put into standby mode, with no possibility to communicate, flying on batteries that were originally not designed for this task.<ref>{{cite news |url=http://www.esa.int/Our_Activities/Space_Science/Rosetta_correctly_lined_up_for_critical_Mars_swingby |title=Rosetta correctly lined up for critical Mars swingby |publisher=European Space Agency |date=15 February 2007 |access-date=21 January 2014}}</ref> This Mars manoeuvre was therefore nicknamed "The Billion Euro Gamble".<ref>{{cite news |url=http://www.physorg.com/news91439922.html |title=Europe set for billion-euro gamble with comet-chasing probe |publisher=[[Phys.org]] |date=23 February 2007 |archive-url=https://web.archive.org/web/20070225091756/http://www.physorg.com/news91439922.html |archive-date=25 February 2007}}</ref> The flyby was successful, with ''Rosetta'' even returning detailed images of the surface and atmosphere of the planet, and the mission continued as planned.<ref name="philaemars20070225"/><ref name="Mars fly-by" />

The second Earth flyby was on 13 November 2007 at a distance of {{convert|5700|km|mi||abbr=on}}.<ref>{{cite news|url=http://www.mps.mpg.de/en/aktuelles/pressenotizen/pressenotiz_20071115.html |title=First OSIRIS images from Rosetta Earth swing-by |publisher=Max Planck Institute for Solar System Research |first1=Horst Uwe |last1=Keller |first2=Holger |last2=Sierks |date=15 November 2007 |archive-url=https://web.archive.org/web/20080307051929/http://www.mps.mpg.de/en/aktuelles/pressenotizen/pressenotiz_20071115.html |archive-date=7 March 2008}}</ref><ref>{{cite web |url=http://www.planetary.org/blogs/emily-lakdawalla/2007/1216.html |title=Science plans for Rosetta's Earth flyby |publisher=The Planetary Society |first=Emily |last=Lakdawalla |date=2 November 2007 |access-date=21 January 2014}}</ref> In observations made on 7 and 8 November, ''Rosetta'' was briefly mistaken for a [[near-Earth object|near-Earth asteroid]] about {{convert|20|m|ft|abbr=on}} in diameter by an astronomer of the [[Catalina Sky Survey]] and was given the [[provisional designation in astronomy|provisional designation]] {{mp|2007 VN|84}}.<ref>{{cite web|title=M.P.E.C. 2007-V69 |url=http://www.minorplanetcenter.net/iau/mpec/K07/K07V69.html |archive-url=https://archive.today/20120523234959/http://www.minorplanetcenter.net/iau/mpec/K07/K07V69.html |url-status=dead |archive-date=23 May 2012 |publisher=Minor Planet Center |access-date=6 October 2015}}</ref> Calculations showed that it would pass very close to Earth, which led to speculation that it could impact Earth.<ref>{{cite news |url=https://www.skymania.com/wp/deadly-asteroid-is-spaceprobe/ |title='Deadly asteroid' is a spaceprobe |work=Skymania |first=Paul |last=Sutherland |date=10 November 2007 |access-date=21 January 2014}}</ref> However, astronomer [[Denis Denisenko]] recognised that the trajectory matched that of ''Rosetta'', which the [[Minor Planet Center]] confirmed in an editorial release on 9 November.<ref name="planetary-misidentification">{{cite web |url=http://www.planetary.org/blogs/emily-lakdawalla/2007/1227.html |title=That's no near-Earth object, it's a spaceship! |publisher=The Planetary Society |first=Emily |last=Lakdawalla |date=9 November 2007 |access-date=21 January 2014}}</ref><ref name="mpec20071109">{{cite web |url=http://www.minorplanetcenter.net/iau/mpec/K07/K07V70.html |title=MPEC 2007-V70: Editorial Notice |work=Minor Planet Electronic Circular |publisher=[[Minor Planet Center]] |first=A. U. |last=Tomatic |date=9 November 2007 |access-date=21 January 2014}}</ref>

The spacecraft performed a close flyby of asteroid [[2867 Šteins]] on 5 September 2008. Its onboard cameras were used to fine-tune the trajectory, achieving a minimum separation of less than {{convert|800|km|abbr=on}}. Onboard instruments measured the asteroid from 4 August to 10 September. Maximum relative speed between the two objects during the flyby was {{convert|8.6|km/s|mph km/h|abbr=on}}.<ref>{{cite journal|title=First Asteroid |journal=[[Aviation Week & Space Technology]] |volume=169 |issue=10 |page=18 |date=15 September 2008}}</ref>

''Rosetta''{{'s}} third and final flyby of Earth happened on 12 November 2009 at a distance of {{convert|2481|km|abbr=on}}.<ref>{{cite news|url=http://news.bbc.co.uk/1/hi/sci/tech/8355873.stm |title=Rosetta makes final home call |work=BBC News |date=12 November 2009 |access-date=22 May 2010}}</ref>

On 10 July 2010, ''Rosetta'' flew by [[21 Lutetia]], a large [[asteroid belt|main-belt]] [[asteroid]], at a minimum distance of {{val|3168|7.5|fmt=commas}}&nbsp;km ({{val|1969|4.7|fmt=commas}}&nbsp;mi) at a velocity of {{convert|15|km/s|mi/s}}.<ref name="science28102011">{{cite journal|title=Asteroid 21 Lutetia: Low Mass, High Density |journal=[[Science (journal)|Science]] |first1=M. |last1=Pätzold |first2=T. P. |last2=Andert |first3=S. W. |last3=Asmar |first4=J. D. |last4=Anderson |first5=J.-P. |last5=Barriot |first6=M. K. |last6=Bird |first7=B. |last7=Häusler |first8=M. |last8=Hahn |first9=S. |last9=Tellmann |first10=H. |last10=Sierks |first11=P. |last11=Lamy |first12=B. P. |last12=Weiss |display-authors=5 |volume=334 |issue=6055 |pages=491–492 |date=October 2011 |bibcode=2011Sci...334..491P |doi=10.1126/science.1209389 |pmid=22034429 |url=https://dspace.mit.edu/bitstream/1721.1/103947/1/Paetzold_2011_open_access.pdf |hdl=1721.1/103947|s2cid=41883019 |hdl-access=free}}</ref> The flyby provided images of up to {{convert|60|m|ft}} per pixel resolution and covered about 50% of the surface, mostly in the northern hemisphere.<ref name=BBC/><ref name="Sierks2011">{{cite journal|title=Images of Asteroid 21 Lutetia: A Remnant Planetesimal from the Early Solar System |journal=[[Science (journal)|Science]] |first1=H. |last1=Sierks |first2=P. |last2=Lamy |first3=C. |last3=Barbieri |first4=D. |last4=Koschny |first5=H. |last5=Rickman |first6=R. |last6=Rodrigo |first7=M. F. |last7=A'Hearn |first8=F. |last8=Angrilli |first9=M. A. |last9=Barucci |first10=J.-L. |last10=Bertaux |first11=I. |last11=Bertini |first12=S. |last12=Besse |first13=B. |last13=Carry |first14=G. |last14=Cremonese |first15=V. |last15=Da Deppo |first16=B. |last16=Davidsson |first17=S. |last17=Debei |first18=M. |last18=De Cecco |first19=J. |last19=De Leon |first20=F. |last20=Ferri |first21=S. |last21=Fornasier |first22=M. |last22=Fulle |first23=S. F. |last23=Hviid |first24=R. W. |last24=Gaskell |first25=O. |last25=Groussin |first26=P. |last26=Gutierrez |first27=W. |last27=Ip |first28=L. |last28=Jorda |first29=M. |last29=Kaasalainen |first30=H. U. |last30=Keller |first31=J. |last31=Knollenberg |first32=R. |last32=Kramm |first33=E. |last33=Kührt |first34=M. |last34=Küppers |first35=L. |last35=Lara |first36=M. |last36=Lazzarin |first37=C. |last37=Leyrat |first38=J. J. Lopez |last38=Moreno |first39=S. |last39=Magrin |first40=S. |last40=Marchi |first41=F. |last41=Marzari |first42=M. |last42=Massironi |first43=H. |last43=Michalik |first44=R. |last44=Moissl |first45=G. |last45=Naletto |first46=F. |last46=Preusker |first47=L. |last47=Sabau |first48=W. |last48=Sabolo |first49=F. |last49=Scholten |first50=C. |last50=Snodgrass |first51=N. |last51=Thomas |first52=C. |last52=Tubiana |first53=P. |last53=Vernazza |first54=J.-B. |last54=Vincent |first55=K.-P. |last55=Wenzel |first56=T. |last56=Andert |first57=M. |last57=Pätzold |first58=B. P. |last58=Weiss |display-authors=5 |volume=334 |issue=6055 |pages=487–90 |date=October 2011 |bibcode=2011Sci...334..487S |doi=10.1126/science.1207325 |pmid=22034428 |hdl=1721.1/110553|s2cid=17580478 |hdl-access=free}}</ref> The 462 images were obtained in 21 narrow- and broad-band filters extending from 0.24 to 1&nbsp;μm.<ref name=BBC/> Lutetia was also observed by the visible–near-infrared imaging spectrometer VIRTIS, and measurements of the magnetic field and plasma environment were taken as well.<ref name=BBC/><ref name=Sierks2011/>

[[File:Signal received from Rosetta (12055070794).jpg|thumb|left|''Rosetta''{{'s}} signal received at [[European Space Operations Centre|ESOC]] in [[Darmstadt]], Germany, on 20 January 2014]]
[[File:Crescent Earth from Rosetta.jpg|thumb|Earth from ''Rosetta'' during final flyby]]

After leaving its hibernation mode in January 2014 and getting closer to the comet, ''Rosetta'' began a series of eight burns in May 2014. These reduced the relative velocity between the spacecraft and 67P from {{convert|775|to|7.9|m/s|abbr=on}}.<ref name="OCM" />