Giotto

Launch data: Designation  15875 / 85056A Launch date  02 Jul 1985 - 11:23:13 UT Launch site  Ko, ELA-1 Launch vehicle  Ariane-1 (V14 L10) Mission  Comet Halley Flyby Operator   Heliocentric orbit Perihelion / Aphelion   Incl. to ecliptic   ° Period   min

Giotto - - Credit: NASA.

Spacecraft data: Prime contractor   Operator  ESA Platform   Mass at launch  583 kg Dry Mass   kg Basic shape   Dimension   Solar array   Stabilization   DC power   Design lifetime

Description:

Mission:

• The spacecraft encountered comet 1P/Halley on March 13, 1986, at a distance of 0.89 AU from the sun and 0.98 AU from the Earth and an angle of 107 degrees from the comet-sun line. The actual closest approach was measured at 596 km. All experiments performed well and returned a wealth of new scientific results, of which perhaps the most important was the clear identification of the cometary nucleus. Fourteen seconds before closest approach, Giotto was hit by a `large' dust particle. The impact caused the spacecraft angular momentum vector to shift 0.9 degrees. Scientific data were received intermittently for the next 32 minutes. Some experiment sensors suffered damage during this 32-minute interval. Other experiments (the camera baffle and deflecting mirror, the dust detector sensors on the front sheet of the bumper shield, and most experiment apertures) were exposed to dust particles regardless of the accident and also suffered damage. Many of the sensors survived the encounter with little or no damage. Questionable or partially damaged sensors included the camera (later proved to not be functional) and one of the plasma analyzers (RPA). Inoperable experiments included the neutral and ion mass spectrometers and one sensor each on the dust detector and the other plasma analyzer (JPA).
• During the Giotto extended mission, the spacecraft successfully encountered Comet 26P/Grigg-Skjellerup on July 10, 1992. The closest approach was approximately 200 km. The heliocentric distance of the spacecraft was 1.01 AU, and the geocentric distance, 1.43 AU at the time of the encounter. The payload was switched-on in the evening of July 9. Eight experiments were operated and provided a surprising wealth of data. The Johnstone Plasma Analyser detected the first presence of cometary ions 600,000 km from the nucleus at 12 hours before the closest approach. The Dust Impact Detectors reported the first impact of a fairly large particle at 15:30:56. Bow shocks/waves and acceleration regions were also detected. After the P/Grigg-Skjellerup encounter operation were terminated on 23 July 1992, the spacecraft will fly by the Earth on 1 July 1999.
• The European Giotto probe skimmed past Earth on Jul 1, 1999 at a distance of 200000 km. Giotto′s been in hibernation since its encounter with comet Grigg-Skjellerup in 1992.

Astrophilately covers:

Launch cancel Kourou. Credit: #410