Editing Giotto (spacecraft) (section)

==Timeline==

===Launch===
The mission was given the go-ahead by ESA in 1980, and launched
on an [[Ariane 1]] rocket (flight V14) on 2 July 1985 from [[Kourou, French Guiana]]. The craft was controlled from the European Space Agency [[European Space Operations Centre|ESOC facilities]] in [[Darmstadt]] (then West Germany) initially in [[Geostationary transfer orbit|Geostationary Transfer Orbit]] (GTO) then in the Near Earth Phase (NEP) before the longer Cruise Phase through to the encounter. While in GTO a number of slew and spin-up manoeuvres (to 90 [[revolutions per minute|RPM]]) were carried out in preparation for the firing of the [[Apogee kick motor|Apogee Boost Motor]] (ABM), although unlike orbit circularisations for [[geostationary orbit]], the ABM for Giotto was fired at [[Apsis|perigee]]. Attitude determination and control used sun pulse and IR [[Earth sensor]] data in the telemetry to determine the spacecraft orientation.

===Halley encounter===

The [[Soviet Union|Soviet]] [[Vega 1]] started returning images of Halley on 4 March 1986, and the first ever of its nucleus, and made its flyby on 6 March, followed by [[Vega 2]] making its flyby on 9 March. Vega 1's closest approach to Halley was
8&thinsp;889&nbsp;km.

''Giotto'' passed Halley successfully on 14 March 1986 at 596&nbsp;km distance, and surprisingly survived despite being hit by some small particles. One impact sent it spinning off its stabilized spin axis so that its antenna no longer always pointed at the Earth, and its dust shield no longer protected its instruments. After 32 minutes ''Giotto'' re-stabilized itself and continued gathering science data.

Another impact destroyed the Halley Multicolor Camera, but not before it took photographs of the nucleus at closest approach.

[[File:Comet Halley close up.jpg|thumb|Comet Halley at Giotto spacecraft's closest approach]]

===First Earth flyby===

''Giotto''{{'}}s trajectory was adjusted for an Earth flyby and its science instruments were turned off on 15 March 1986 at 02:00 UTC.

===Grigg–Skjellerup encounter===

''Giotto'' was commanded to wake up on 2 July 1990 when it flew by Earth in order to sling shot to its next cometary encounter.

The probe then flew by the [[26P/Grigg–Skjellerup|Comet Grigg–Skjellerup]] on 10 July 1992 which it approached to a distance of about 200&nbsp;km. Afterwards, Giotto was again switched off on 23 July 1992.

The cost of this mission extension was $6.3 million.<ref>{{cite journal |last1=Holden |first1=Constance |date=10 July 1992 |title=Random Samples  |url=http://www.jstor.org/stable/2877514  |journal=Science |volume=257 |issue=5067 |pages=160-161  |access-date=11 March 2025}}</ref>

===Second Earth flyby===

In 1999 ''Giotto'' made another Earth flyby but was not reactivated.<ref name=Portree />