Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Giotto Mission shopping experience:
1. Compare - without doubt the biggest advantage that the Giotto Mission offers shoppers today is the ability to compare thousands of Giotto Mission at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.
2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Giotto Mission? Wrong! If the Giotto Mission is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Giotto Mission then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Giotto Mission? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Giotto Mission and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Giotto Mission wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Giotto Mission then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Giotto Mission site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Giotto Mission, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Giotto Mission, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
{{Infobox_Spacecraft| Name = Giotto| Image = | Caption = Artist's concept of Giotto| Organization =
European Space Agency, [Comet Grigg-Skjellerup,
Earth, [1986, (Grigg-Skjellerup)
July 10, 1992, [1985 rocket| Decay =| Mission_Duration = Ended on [July 23, 1992an [robotic spacecraft mission from the European Space Agency, intended to fly by and study
Comet Halley. On
March 13, 1986, the mission succeeded in approaching Halley's nucleus at a distance of 1 E5 m
kilometers.The spacecraft was named after the medieval
Italy painter Giotto di Bondone. He had observed Halley's Comet in 1301 and was inspired to depict it as the star of Bethlehem in his painting Adoration of the Magi.
Mission
Originally a United States partner probe was planned that would accompany Giotto, but this fell through due to budget cuts at NASA. There were plans to have observation equipment on-board a Space Shuttle in low-Earth orbit around the time of Giotto's fly-by, but they fell through with the
STS-51-L.
The plan then became a cooperative armada of five spaceprobes including Giotto, two from the Soviet Union's
Vega program and two from
Japan: the
Sakigake and Suisei probes. The idea was for Japanese probes and the pre-existing
United States probe International Cometary Explorer to make long distance measurements, followed by the Russian Vegas which would locate the nucleus, and the resulting information sent back would allow Giotto to precisely target very close to the nucleus. Because Giotto would pass so very close to the nucleus ESA was mostly convinced it would not survive the encounter due to bombardment from the many high speed cometary particles. The coordinated group of probes became known as the
Halley Armada.
The craft
The spacecraft is derived from the GEOS research satellite built by British Aerospace, and modified with the addition of a dust shield as proposed by
Fred Whipple and comprising a thin aluminium sheet separated by a space and a thicker Kevlar sheet. The later Stardust (spacecraft) would use a similar Whipple shield.
Timeline
Launch
The mission was given the go-ahead by ESA in 1980, and launchedon an Ariane 1 rocket (flight V14) on
1985 July 2 from Kourou. The craft was controlled from the European Space Agency European Space Operations Centre in Darmstadt (then West Germany) initially in 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 RPM) were carried out in preparation for the firing of the Apogee Boost Motor (ABM), although unlike orbit circularisations for Geostationary Orbit, the ABM for Giotto was fired at 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 Vega 1 starts returning images of Halley on 1986
March 4, and the first ever of its nucleus, and made its flyby on March 6, followed by
Vega 2 making its flyby on March 9.
Giotto passed Halley successfully on 1986
March 14 at 1 E5 m kilometre 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 importantly, 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 spectacular pictures of the nucleus at closest approach.
First Earth flyby
Giotto's trajectory was adjusted for a Earth flyby and its science instruments were turned off on 1986
March 15 at 02:00 UT.
Grigg-Skjellerup encounter
Giotto was commanded to wake up and on July 2, 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 in
July 10,
1992 which it approached to a distance of about 200 kilometres. Afterwards, Giotto was again switched off on July 23, 1992.
Second Earth flyby
In 1999 Giotto made another Earth flyby but was not reactivated.
Results
Scientific Results
Images showed Halley's nucleus to be a dark peanut-shaped body, 15 km long, 7 to 10 km wide. Only 10% of the surface was active, with at least three outgassing jets seen on the sunlit side. Analysis showed the comet formed 4.5 billion years ago from volatiles (mainly ice) that had condensed onto interstellar dust particles. It had remained practically unaltered since its formation.
Measured volume of material ejected by Halley:
Halley's nucleus was blacker than soot, which suggests there is proportionally more dust than ice.
The nucleus's surface was rough and of a porous quality, with the density of whole nucleus only 0.3 kg/m³.
The quantity of material ejected was found to be 3 tonnes per second for seven jets, and these caused the comet to wobble over long time periods.
The dust ejected was mostly only the size of cigarette smoke particles, the largest being 40 milligram. Although the one that sent Giotto spinning was not measured, from its effects its mass has been estimated to lie between 0.1 and 1 gram.
Two kinds of dust were seen: one with carbon, hydrogen, nitrogen and oxygen; the other with calcium, iron, magnesium, silicon and sodium.
The ratio of abundances of the comet's light elements excluding nitrogen (ie. hydrogen, carbon, oxygen) were the same as the Sun's. The implication is that the constituents of Halley are among the most primitive in the solar system.
The plasma and ion mass spectrometer instruments showed Halley has a carbon-rich surface.
Spacecraft achievements
- Giotto made the closest approach to Halley comet and provided the best data for this comet.
- Giotto was the first spacecraft to provide pictures of a cometary nucleus.
- Giotto was the first spacecraft do a close flyby of two comets. Young and active comet Halley could be compared to old Grigg-Skjellerup.
- Giotto was the first spacecraft to return from interplanetary space and perform a Earth swing by.
- Giotto was the first spacecraft to be re-activated from hibernation mode.
External links
- Official site
- Interview with the mission's Deputy Project Scientist by NASA's Solar System Exploration
- Nature 1986 about Giotto mission
- Giotto di Bondone's 'Adoration of the Magi' painting that includes his rendition of Halley's Comet
{{Infobox_Spacecraft| Name = Giotto| Image = | Caption = Artist's concept of Giotto| Organization =
European Space Agency, [Comet Grigg-Skjellerup,
Earth, [1986, (Grigg-Skjellerup)
July 10,
1992, [1985 rocket| Decay =| Mission_Duration = Ended on [July 23,
1992an [robotic spacecraft mission from the
European Space Agency, intended to fly by and study Comet Halley. On
March 13,
1986, the mission succeeded in approaching Halley's nucleus at a distance of
1 E5 m kilometers.The spacecraft was named after the medieval Italy
painter Giotto di Bondone. He had observed Halley's Comet in 1301 and was inspired to depict it as the
star of Bethlehem in his painting
Adoration of the Magi.
Mission
Originally a United States partner probe was planned that would accompany Giotto, but this fell through due to budget cuts at
NASA. There were plans to have observation equipment on-board a Space Shuttle in low-Earth orbit around the time of Giotto's fly-by, but they fell through with the STS-51-L.
The plan then became a cooperative armada of five spaceprobes including Giotto, two from the Soviet Union's
Vega program and two from Japan: the Sakigake and Suisei probes. The idea was for Japanese probes and the pre-existing
United States probe International Cometary Explorer to make long distance measurements, followed by the Russian Vegas which would locate the nucleus, and the resulting information sent back would allow Giotto to precisely target very close to the nucleus. Because Giotto would pass so very close to the nucleus ESA was mostly convinced it would not survive the encounter due to bombardment from the many high speed cometary particles. The coordinated group of probes became known as the Halley Armada.
The craft
The spacecraft is derived from the GEOS research satellite built by British Aerospace, and modified with the addition of a dust shield as proposed by
Fred Whipple and comprising a thin aluminium sheet separated by a space and a thicker Kevlar sheet. The later Stardust (spacecraft) would use a similar Whipple shield.
Timeline
Launch
The mission was given the go-ahead by ESA in 1980, and launchedon an
Ariane 1 rocket (flight V14) on 1985
July 2 from
Kourou. The craft was controlled from the European Space Agency European Space Operations Centre in Darmstadt (then West Germany) initially in 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 RPM) were carried out in preparation for the firing of the Apogee Boost Motor (ABM), although unlike orbit circularisations for Geostationary Orbit, the ABM for Giotto was fired at 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
Vega 1 starts returning images of Halley on
1986 March 4, and the first ever of its nucleus, and made its flyby on March 6, followed by Vega 2 making its flyby on March 9.
Giotto passed Halley successfully on
1986 March 14 at
1 E5 m kilometre 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 importantly, 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 spectacular pictures of the nucleus at closest approach.
First Earth flyby
Giotto's trajectory was adjusted for a Earth flyby and its science instruments were turned off on 1986
March 15 at 02:00 UT.
Grigg-Skjellerup encounter
Giotto was commanded to wake up and on
July 2, 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 in July 10, 1992 which it approached to a distance of about 200 kilometres. Afterwards, Giotto was again switched off on
July 23, 1992.
Second Earth flyby
In 1999 Giotto made another Earth flyby but was not reactivated.
Results
Scientific Results
Images showed Halley's nucleus to be a dark peanut-shaped body, 15 km long, 7 to 10 km wide. Only 10% of the surface was active, with at least three outgassing jets seen on the sunlit side. Analysis showed the comet formed 4.5 billion years ago from volatiles (mainly ice) that had condensed onto interstellar dust particles. It had remained practically unaltered since its formation.
Measured volume of material ejected by Halley:
Halley's nucleus was blacker than soot, which suggests there is proportionally more dust than ice.
The nucleus's surface was rough and of a porous quality, with the density of whole nucleus only 0.3 kg/m³.
The quantity of material ejected was found to be 3 tonnes per second for seven jets, and these caused the comet to wobble over long time periods.
The dust ejected was mostly only the size of cigarette smoke particles, the largest being 40 milligram. Although the one that sent Giotto spinning was not measured, from its effects its mass has been estimated to lie between 0.1 and 1 gram.
Two kinds of dust were seen: one with carbon, hydrogen, nitrogen and oxygen; the other with calcium, iron, magnesium, silicon and sodium.
The ratio of abundances of the comet's light elements excluding nitrogen (ie. hydrogen, carbon, oxygen) were the same as the Sun's. The implication is that the constituents of Halley are among the most primitive in the solar system.
The plasma and ion mass spectrometer instruments showed Halley has a carbon-rich surface.
Spacecraft achievements
- Giotto made the closest approach to Halley comet and provided the best data for this comet.
- Giotto was the first spacecraft to provide pictures of a cometary nucleus.
- Giotto was the first spacecraft do a close flyby of two comets. Young and active comet Halley could be compared to old Grigg-Skjellerup.
- Giotto was the first spacecraft to return from interplanetary space and perform a Earth swing by.
- Giotto was the first spacecraft to be re-activated from hibernation mode.
External links
- Official site
- Interview with the mission's Deputy Project Scientist by NASA's Solar System Exploration
- Nature 1986 about Giotto mission
- Giotto di Bondone's 'Adoration of the Magi' painting that includes his rendition of Halley's Comet
Giotto mission - Wikipedia, the free encyclopedia
Giotto was a European robotic spacecraft mission from the European Space Agency, intended to fly by and study Halley's Comet. On March 13, 1986, the mission succeeded in ...
Giotto Information
Information on the European mission to Halley's Comet (1985-1992).
ESA Science & Technology: Giotto
LAUNCH DATE: 02-Jul-1985 11:23 UT MISSION END: 23-July-1992: LAUNCH VEHICLE: Ariane 1 rocket (flight V14) LAUNCH MASS: 960 kg: MISSION PHASE: Archive
Giotto (disambiguation) - Wikipedia, the free encyclopedia
Giotto may refer to: Giotto di Bondone an Italian painter. Giotto mission, an ESA space mission for the observation of Halley's comet; The Giotto programming language for real-time ...
GIOTTO
Overview of the ESA GIOTTO Mission ... The objective of the Giotto mission was to pass close by to Comet Halley (1P/Halley) and using its range of instruments examine the comet at ...
Results: Giotto mission
Giotto Information: 100% | | | | | | | | | | | | | | | | | | | |... The Giotto mission was designed to study Comet P/Halley ...
SBN Mission Support: Giotto
Giotto Mission. The Giotto spacecraft was launched on 2 July 1985 to study comet 1P/Halley. The spacecraft carried instruments to image the nucleus, analyze components of the ...
ESA - Space Science - Giotto overview
SCI_Mission.abstract ... Status Completed (1992) Objective Making encounters with comets Halley and Grigg–Skjellerup, Giotto was ESA’s first deep-space mission.
Giotto - MSN Encarta
Giotto mission - Wikipedia, the free encyclopedia. Giotto was a European robotic spacecraft mission from the European Space Agency, intended to fly by and study Halley's Comet.
Giotto
The Giotto spacecraft, named after Italian painter, Giotto di Bondone, who had included Halley's comet in his 1304 painting of Bethlehem, was launched on July 2, 1985.
