Editing Venus Express (section)

==History==
The mission was proposed in 2001 to reuse the design of the ''[[Mars Express]]'' mission. However, some mission characteristics led to [[design]] changes: primarily in the areas of thermal control, communications and electrical power. For example, since [[Mars]] is approximately twice as far from the [[Sun]] as Venus, the radiant heating of the spacecraft is four times greater for ''Venus Express'' than ''Mars Express''. Also, the [[ionizing radiation]] environment is harsher. On the other hand, the more intense illumination of the [[Photovoltaic module|solar panels]] results in more generated [[solar cell|photovoltaic]] power. The ''Venus Express'' mission also uses some spare instruments developed for the ''[[Rosetta space probe|Rosetta]]'' spacecraft. The mission was proposed by a consortium led by D. Titov (Germany), E. Lellouch (France) and F. Taylor (United Kingdom).

The [[launch window]] for ''Venus Express'' was open from 26 October to 23 November 2005, with the launch initially set for 26 October 4:43 [[Coordinated Universal Time|UTC]]. However, problems with the insulation from the Fregat upper stage led to a two-week launch delay to inspect and clear out the small insulation debris that migrated on the spacecraft.<ref>{{cite web |url=http://www.esa.int/SPECIALS/Venus_Express/SEM2714J2FE_0.html |title=Venus Express preliminary investigations bring encouraging news |date=25 October 2005 |publisher=ESA |access-date=9 May 2006}}</ref> It was eventually launched by a [[Soyuz-FG]]/[[Fregat]] rocket from the [[Baikonur Cosmodrome]] in [[Kazakhstan]] on 9 November 2005 at 03:33:34 UTC into a parking Earth orbit and 1&nbsp;h 36&nbsp;min after launch put into its transfer orbit to Venus. A first trajectory correction maneuver was successfully performed on 11 November 2005. It arrived at Venus on 11 April 2006, after 153 days of journey, and fired its main engine between 07:10:29 and 08:00:42 [[UTC]] [[Spacecraft Event Time|SCET]] to reduce its velocity so that it could be captured by Venusian [[gravity]] into a nine-day orbit of {{convert|400|by|330000|km|mi}}.<ref name="nssdc">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2005-045A |title=Venus Express |work=[[National Space Science Data Center]] |access-date=22 December 2014}}</ref> The burn was monitored from ESA's Control Centre, [[ESOC]], in [[Darmstadt, Germany]].

Seven further orbit control maneuvers, two with the main engine and five with the [[Rocket engine|thrusters]], were required for ''Venus Express'' to reach its final operational 24-hour orbit around Venus.<ref name="nssdc"/>

''Venus Express'' entered its target orbit at apoapsis on 7 May 2006 at 13:31 UTC, when the spacecraft was {{convert|151000000|km|mi}} from Earth. At this point the spacecraft was running on an [[ellipse]] substantially closer to the planet than during the initial orbit. The polar orbit ranged between {{convert|250|and|66000|km|mi}} over Venus. The [[periapsis]] was located almost above the North pole (80° North latitude), and it took 24 hours for the spacecraft to travel around the planet.

''Venus Express'' studied the [[Venusian atmosphere]] and clouds in detail, the [[Plasma (physics)|plasma]] environment and the surface characteristics of Venus from orbit. It also made global maps of the Venusian surface temperatures. Its nominal mission was originally planned to last for 500 Earth days (approximately two Venusian sidereal days), but the mission was extended five times: first on 28 February 2007 until early May 2009; then on 4 February 2009 until 31 December 2009; and then on 7 October 2009 until 31 December 2012.<ref>{{cite web |url=http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=45685 |title=Mission extensions approved for science missions |date=16 October 2009 |publisher=ESA}}</ref> On 22 November 2010, the mission was extended to 2014.<ref>{{cite web |url=http://sci.esa.int/director-desk/48007-europe-maintains-its-presence-on-the-final-frontier/ |title=Europe maintains its presence on the final frontier |publisher=ESA |date=22 November 2010}}</ref> On 20 June 2013, the mission was extended a final time until 2015.<ref>{{cite web |url=http://sci.esa.int/director-desk/51944-esa-science-missions-continue-in-overtime/ |title=ESA science missions continue in overtime |publisher=ESA |date=20 June 2013}}</ref>

On 28 November 2014, mission control lost contact with ''Venus Express''. Intermittent contact was reestablished on 3 December 2014, though there was no control over the spacecraft, likely due to exhaustion of propellant.<ref name=SpaceDaily-2014-12-08/> On 16 December 2014, ESA announced that the ''Venus Express'' mission had ended.<ref name="esa20141216"/> A [[carrier signal]] was still being received from the vehicle, but no data was being transmitted. Mission manager Patrick Martin expected the spacecraft would fall below {{convert|150|km|mi}} in early January 2015, with destruction occurring in late January or early February.<ref name="natgeo20141217">{{cite news |url=http://news.nationalgeographic.com/news/2014/12/141217-venus-express-final-plunge-space-science/ |archive-url=https://web.archive.org/web/20141218020323/http://news.nationalgeographic.com/news/2014/12/141217-venus-express-final-plunge-space-science/ |url-status=dead |archive-date=18 December 2014 |title=Out of Fuel, Venus Express Is Falling Gently to Its Death in Planet's Skies |work=National Geographic |first=Nadia |last=Drake |author-link=Nadia Drake |date=17 December 2014 |access-date=22 December 2014}}</ref> The spacecraft's carrier signal was last detected by ESA on 18 January 2015.<ref name="esa20150123"/>