Encyclopedia Astronautica
Giotto



giotto.jpg
Giotto
Credit: NASA
European comet probe. One launch, 1985.07.02. The Giotto mission was designed to study Comet P/Halley, and also studied Comet P/Grigg-Skjellerup during its extended mission.

The major objectives of the mission were to: (1) obtain color photographs of the nucleus; (2) determine the elemental and isotopic composition of volatile components in the cometary coma, particularly parent molecules; (3) characterize the physical and chemical processes that occur in the cometary atmosphere and ionosphere; (4) determine the elemental and isotopic composition of dust particles; (5) measure the total gas-production rate and dust flux and size/mass distribution and derive the dust-to-gas ratio; and, (6) investigate the macroscopic systems of plasma flows resulting from the cometary-solar wind interaction. The goal was to come within 500 km of Halley's comet at closest encounter. The spacecraft had a dust shield consisting of a front sheet of Aluminum (1 mm thick) and a 12 mm Kevlar near sheet separated by 25 cm, which could withstand impacts of particles up to 0.1 g. The scientific payload was comprised of ten hardware experiments: a narrow-angle camera, three mass spectrometers for neutrals, ions and dust, various dust detectors, a photopolarimeter and a set of plasma experiments.

Electric System: 0.196 average kW.

Gross mass: 583 kg (1,285 lb).
First Launch: 1985.07.02.
Number: 1 .

More... - Chronology...


Associated Countries
See also
  • Ariane First successful European commercial launch vehicle, developed from L3S Europa launch vehicle replacement design. Development of the Ariane 1 was authorised in July 1973, took eight years, and cost 2 billion 1986 Euros. More...

Associated Launch Vehicles
  • Ariane French orbital launch vehicle. First successful European commercial launch vehicle, developed from L3S Europa launch vehicle replacement design. Development of the Ariane 1 was authorised in July 1973, took eight years, and cost 2 billion 1986 Euros. More...
  • Ariane 1 French orbital launch vehicle. First version of the Ariane launch vehicle. More...

Associated Manufacturers and Agencies
  • ESA European agency overseeing development of rockets and spacecraft. European Space Agency, Europe. More...

Bibliography
  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.
  • JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. Web Address when accessed: here.
  • National Space Science Center Planetary Page, As of 19 February 1999.. Web Address when accessed: here.

Associated Launch Sites
  • Kourou After the agreement with newly independent Algeria for France to evacuate their launch sites in that country, a location near Biscarosse was selected for French missile testing. However since only launches westwards across the Bay of Biscay could be made from this site, it was unsuitable for France's Diamant orbital launch vehicle. After reviewing 14 potential sites, a location in the South American French colony of Guiana was selected. This would allow over-water launches to a tremendous range of possible orbital inclinations -- from -100.5 deg to 1.5 deg. Being near the equator, it would provide the maximum assist from the earth's rotation for launches into equatorial orbits. The decision was formalized in April 1964 and in July 1966 ELDO chose the site for future launches of the Europa II launch vehicle. More...

Giotto Chronology


1985 July 2 - . 11:23 GMT - . Launch Site: Kourou. Launch Complex: Kourou ELA1. LV Family: Ariane. Launch Vehicle: Ariane 1. LV Configuration: Ariane 1 V14.
  • Giotto - . Mass: 583 kg (1,285 lb). Nation: Europe. Agency: ESA. Class: Comet. Type: Comet probe. Spacecraft: Giotto. USAF Sat Cat: 15875 . COSPAR: 1985-056A. Apogee: 35,807 km (22,249 mi). Perigee: 201 km (124 mi). Inclination: 6.9000 deg. Period: 631.51 min. Encountered comet Halley March 13, 1986. The Giotto mission was designed to study Comet P/Halley, and also studied Comet P/Grigg-Skjellerup during its extended mission. The spacecraft encountered 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 P/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.

1986 March 13 - .
  • Giotto, Comet Halley Flyby - . Nation: Europe. Spacecraft: Giotto.

1990 July 2 - .
  • Giotto, Earth Flyby - . Nation: Europe. Spacecraft: Giotto.

1992 July 10 - .
  • Giotto Flyby of Comet Grigg-Skjellerup - . Nation: Europe. Spacecraft: Giotto.

1999 July 1 - .
  • Giotto, Earth Flyby - . Nation: Europe. Spacecraft: Giotto.

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