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The Gravity Field and Steady-State Ocean Circulation Explorer ( GOCE ) was the first of ESA 's Living Planet Programme heavy satellites intended to map in unprecedented detail the Earth's gravity field . The spacecraft's primary instrumentation was a highly sensitive gravity gradiometer consisting of three pairs of accelerometers which measured gravitational gradients along three orthogonal axes.

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66-505: Launched on 17 March 2009, GOCE mapped the deep structure of the Earth's mantle and probed hazardous volcanic regions. It brought new insight into ocean behaviour; this in particular, was a major driver for the mission. By combining the gravity data with information about sea surface height gathered by other satellite altimeters, scientists were able to track the direction and speed of geostrophic ocean currents . The low orbit and high accuracy of

132-485: A Satellite-to-Satellite Tracking Instrument (SSTI); a compensation system for all non-gravitational forces acting on the spacecraft. The satellite was also equipped with a laser retroreflector to enable tracking by ground-based Satellite laser ranging stations. GOCE's 5 × 1.1 m (16 × 4 ft) frame had fixed solar panels covering its sun-facing side, which produced 1,300  watts of power. The panels were shaped to act as fins, stabilising

198-568: A consequence its citizens became eligible to apply to the 2022 ESA Astronaut group , applications for which were scheduled to close one week later. The deadline was therefore extended by three weeks to allow Lithuanians a fair chance to apply. Slovakia's Associate membership came into effect on 13 October 2022, for an initial duration of seven years. The Association Agreement supersedes the European Cooperating State (ECS) Agreement, which entered into force upon Slovakia's subscription to

264-455: A full member of the ESA do so in 3 stages. First a Cooperation Agreement is signed between the country and ESA. In this stage, the country has very limited financial responsibilities. If a country wants to co-operate more fully with ESA, it signs a European Cooperating State (ECS) Agreement, albeit to be a candidate for said agreement, a country must be European. The ECS Agreement makes companies based in

330-585: A full member of the ESA on 1 January 2025, when the current Association Agreement expires. Latvia became the second current associated member on 30 June 2020, when the Association Agreement was signed by ESA Director Jan Wörner and the Minister of Education and Science of Latvia , Ilga Šuplinska in Riga . The Saeima ratified it on 27 July. In May 2021, Lithuania became the third current associated member. As

396-486: A further lowering to 229 km (142 mi) took place. The satellite ran out of its xenon propellant in October 2013, at which time it would take 2–3 weeks to re-enter. On 18 October 2013, ESA reported that the pressure in the fuel system of GOCE's ion engine had dropped below 2.5 bar, which is the nominal operating pressure required to fire the engine. Subsequently, end of mission was formally declared on 21 October when

462-431: A higher quality of life, better security, more economic wealth, and also fulfill our citizens' dreams and thirst for knowledge, and attract the young generation. This is the reason space exploration is an integral part of overall space activities. It has always been so, and it will be even more important in the future. The ESA describes its work in two overlapping ways: These are either mandatory or optional. According to

528-556: A launch system, ELDO (European Launcher Development Organisation), and the other the precursor of the European Space Agency, ESRO (European Space Research Organisation). The latter was established on 20 March 1964 by an agreement signed on 14 June 1962. From 1968 to 1972, ESRO launched seven research satellites, but ELDO was not able to deliver a launch vehicle. Both agencies struggled with the underfunding and diverging interests of their participants. The ESA in its current form

594-472: A milestone in the search for exoplanets . On 21 January 2019, ArianeGroup and Arianespace announced a one-year contract with the ESA to study and prepare for a mission to mine the Moon for lunar regolith . In 2021 the ESA ministerial council agreed to the " Matosinhos manifesto" which set three priority areas (referred to as accelerators ) "space for a green future, a rapid and resilient crisis response, and

660-430: A number of asteroids , and some planetary moons have mantles. The Earth's mantle is a layer of silicate rock between the crust and the outer core . Its mass of 4.01 × 10 kg is 67% the mass of the Earth. It has a thickness of 2,900 kilometres (1,800 mi) making up about 84% of Earth's volume. It is predominantly solid, but in geological time it behaves as a viscous fluid . Partial melting of

726-484: A provision ensuring a fair industrial return to Canada. The most recent Cooperation Agreement was signed on 15 December 2010 with a term extending to 2020. For 2014, Canada's annual assessed contribution to the ESA general budget was €6,059,449 ( CAD$ 8,559,050). For 2017, Canada has increased its annual contribution to €21,600,000 ( CAD$ 30,000,000). The ESA is funded from annual contributions by national governments of members as well as from an annual contribution by

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792-421: A seismic discontinuity at ~500 kilometers (310 miles) depth, most likely related to a change in composition. Titan and Triton each have a mantle made of ice or other solid volatile substances. Some of the largest asteroids have mantles; for example, Vesta has a silicate mantle similar in composition to diogenite meteorites. European Space Agency The European Space Agency ( ESA )

858-467: A view to their being used for scientific purposes and for operational space applications systems… The ESA is responsible for setting a unified space and related industrial policy, recommending space objectives to the member states, and integrating national programs like satellite development, into the European program as much as possible. Jean-Jacques Dordain – ESA's Director General (2003–2015) – outlined

924-711: A while already and which gives effect to these. Thanks Jan for your hand of friendship and making this possible." The ESA currently has two operational launch vehicles Vega-C and Ariane 6 . Rocket launches are carried out by Arianespace , which has 23 shareholders representing the industry that manufactures the Ariane 5 as well as CNES , at the ESA's Guiana Space Centre . Because many communication satellites have equatorial orbits, launches from French Guiana are able to take larger payloads into space than from spaceports at higher latitudes . In addition, equatorial launches give spacecraft an extra 'push' of nearly 500 m/s due to

990-590: Is a 22-member intergovernmental body devoted to space exploration . With its headquarters in Paris and a staff of around 2,547 people globally as of 2023, the ESA was founded in 1975. Its 2024 annual budget was €7.8 billion. The ESA's space flight programme includes human spaceflight (mainly through participation in the International Space Station program); the launch and operation of crewless exploration missions to other planets (such as Mars ) and

1056-403: Is a layer inside a planetary body bounded below by a core and above by a crust . Mantles are made of rock or ices , and are generally the largest and most massive layer of the planetary body. Mantles are characteristic of planetary bodies that have undergone differentiation by density . All terrestrial planets (including Earth ), half of the giant planets , specifically ice giants ,

1122-477: Is a widespread harassment between management and its employees, especially with its contractors. Since the ESA is an international organization, unaffiliated with any single nation, any form of legal action is difficult to raise against the organization. Member states participate to varying degrees with both mandatory space programs and those that are optional. As of 2008 , the mandatory programmes made up 25% of total expenditures while optional space programmes were

1188-588: Is already underway in two different areas of launcher activity that will bring benefits to both partners. Notable ESA programmes include SMART-1 , a probe testing cutting-edge space propulsion technology, the Mars Express and Venus Express missions, as well as the development of the Ariane 5 rocket and its role in the ISS partnership. The ESA maintains its scientific and research projects mainly for astronomy-space missions such as Corot , launched on 27 December 2006,

1254-463: Is approximately 1,600 kilometers (990 miles) thick, constituting ~74–88% of its mass, and may be represented by chassignite meteorites. Uranus and Neptune 's ice mantles are approximately 30,000 km thick, composing 80% of both masses. Jupiter 's moons Io , Europa , and Ganymede have silicate mantles; Io's ~1,100 kilometers (680 miles) silicate mantle is overlain by a volcanic crust, Ganymede's ~1,315 kilometers (817 miles) thick silicate mantle

1320-517: Is at an advanced stage" with these nations and that "prospects for mutual benefits are existing". A separate space exploration strategy resolution calls for further co-operation with the United States, Russia and China on " LEO exploration, including a continuation of ISS cooperation and the development of a robust plan for the coordinated use of space transportation vehicles and systems for exploration purposes, participation in robotic missions for

1386-567: Is capable of carrying a payload with a mass of between 300 and 1500 kg to an altitude of 700 km, for low polar orbit . Its maiden launch from Kourou was on 13 February 2012. Vega began full commercial exploitation in December 2015. The rocket has three solid propulsion stages and a liquid propulsion upper stage (the AVUM ) for accurate orbital insertion and the ability to place multiple payloads into different orbits. A larger version of

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1452-607: Is designed to better understand dark energy and dark matter by accurately measuring the accelerating expansion of the universe . The agency's facilities date back to ESRO and are deliberately distributed among various countries and areas. The most important are the following centres: The treaty establishing the European Space Agency reads: The purpose of the Agency shall be to provide for and to promote, for exclusively peaceful purposes, cooperation among European States in space research and technology and their space applications, with

1518-580: Is overlain by ~835 kilometers (519 miles) of ice, and Europa's ~1,165 kilometers (724 miles) km silicate mantle is overlain by ~85 kilometers (53 miles) of ice and possibly liquid water. The silicate mantle of the Earth's moon is approximately 1300–1400 km thick, and is the source of mare basalts . The lunar mantle might be exposed in the South Pole-Aitken basin or the Crisium basin . The lunar mantle contains

1584-455: The European Union (EU). The budget of the ESA was €5.250 billion in 2016. Every 3–4 years, ESA member states agree on a budget plan for several years at an ESA member states conference. This plan can be amended in future years, however provides the major guideline for the ESA for several years. The 2016 budget allocations for major areas of the ESA activity are shown in the chart on

1650-538: The Orion spacecraft service module that flies on the Space Launch System . After World War II , many European scientists left Western Europe in order to work with the United States. Although the 1950s boom made it possible for Western European countries to invest in research and specifically in space-related activities, Western European scientists realised solely national projects would not be able to compete with

1716-525: The Titan landing module Huygens . As the successor of ELDO , the ESA has also constructed rockets for scientific and commercial payloads. Ariane 1 , launched in 1979, carried mostly commercial payloads into orbit from 1984 onward. The next two versions of the Ariane rocket were intermediate stages in the development of a more advanced launch system, the Ariane 4 , which operated between 1988 and 2003 and established

1782-535: The United States military ) led to decisions to rely more on itself and on co-operation with Russia. A 2011 press issue thus stated: Russia is ESA's first partner in its efforts to ensure long-term access to space. There is a framework agreement between ESA and the government of the Russian Federation on cooperation and partnership in the exploration and use of outer space for peaceful purposes, and cooperation

1848-423: The 'gravitational tug' of the Earth as it traveled along its orbital path. Because of their different position in the gravitational field they all experienced the gravitational acceleration of the Earth slightly differently. The three axes of the gradiometer allowed the simultaneous measurement of the five independent components of the gravity gradient tensor . Other payload was an onboard GPS receiver used as

1914-600: The Antarctic ice. The first launch attempt on 16 March 2009 was aborted due to a malfunction with the launch tower. GOCE was launched on 17 March 2009 at 14:21 UTC from the Plesetsk Cosmodrome in northern Russia aboard a Rokot / Briz-KM vehicle. The Rokot is a modified UR-100N intercontinental ballistic missile that was decommissioned after the Strategic Arms Reduction Treaty. The launcher used

1980-511: The Ariane 6 to launch in June or July 2024. The beginning of the new millennium saw the ESA become, along with agencies like NASA, JAXA , ISRO , the CSA and Roscosmos , one of the major participants in scientific space research . Although the ESA had relied on co-operation with NASA in previous decades, especially the 1990s, changed circumstances (such as tough legal restrictions on information sharing by

2046-511: The ESA as full members. Since October 2022 there have been five associate members: Slovenia, Latvia, Lithuania, Slovakia and Canada. The four European members have shown interest in full membership and may eventually apply within the next years. Since 2016, Slovenia has been an associated member of the ESA. In November 2023 Slovenia formally applied for full membership. In June 2024 Prime Minister Robert Golob and Director General Josef Aschbacher have signed an agreement that will see Slovenia become

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2112-490: The ESA as the world leader in commercial space launches in the 1990s. Although the succeeding Ariane 5 experienced a failure on its first flight, it has since firmly established itself within the heavily competitive commercial space launch market with 112 successful launches until 2021. The successor launch vehicle, the Ariane 6 , is under development and had a successful long-firing engine test in November 2023. The ESA plans for

2178-531: The ESA began Giotto , its first deep-space mission, to study the comets Halley and Grigg–Skjellerup . Hipparcos , a star-mapping mission, was launched in 1989 and in the 1990s SOHO , Ulysses and the Hubble Space Telescope were all jointly carried out with NASA. Later scientific missions in cooperation with NASA include the Cassini–Huygens space probe, to which the ESA contributed by building

2244-533: The ESA is not the only European governmental space organisation (for example European Union Satellite Centre and the European Union Space Programme Agency ). After the decision of the ESA Council of 21/22 March 2001, the procedure for accession of the European states was detailed as described the document titled "The Plan for European Co-operating States (PECS)". Nations that want to become

2310-479: The ESA website, the activities are: Every member country (known as 'Member States') must contribute to these programmes: The European Space Agency Science Programme is a long-term programme of space science missions. Depending on their individual choices the countries can contribute to the following programmes, becoming 'Participating States', listed according to: As of 2023, Many other facilities are operated by national space agencies in close collaboration with

2376-572: The ESA. The ESA employs around 2,547 people, and thousands of contractors. Initially, new employees are contracted for an expandable four-year term, which is until the organization's retirement age of 63. According to the ESA's documents, the staff can receive myriad of perks, such as financial childcare support, retirement plans, and financial help when migrating. The ESA also prevents employees from disclosing any private documents or correspondences to outside parties. Ars Technica ' s 2023 report, which contained testimonies of 18 people, suggested that there

2442-444: The European Space Agency's mission in a 2003 interview: Today space activities have pursued the benefit of citizens, and citizens are asking for a better quality of life on Earth. They want greater security and economic wealth, but they also want to pursue their dreams, to increase their knowledge, and they want younger people to be attracted to the pursuit of science and technology. I think that space can do all of this: it can produce

2508-594: The GOCE data show ocean currents in much finer detail than had been available previously. Even very small details like the Mann Eddy in the North Atlantic were visible in the data, as was the effect of Hurricane Igor in 2010. Detailed analysis of GOCE's thruster and accelerometer data serendipitously revealed that it had detected the infrasound waves generated by the 2011 Tōhoku earthquake (whereupon it inadvertently became

2574-479: The Moon; Earth observation, science and telecommunication; designing launch vehicles ; and maintaining a major spaceport , the Guiana Space Centre at Kourou ( French Guiana ), France. The main European launch vehicle Ariane 6 will be operated through Arianespace with the ESA sharing in the costs of launching and further developing this launch vehicle. The agency is also working with NASA to manufacture

2640-631: The Plan for European Cooperating States Charter on 4 February 2016, a scheme introduced at ESA in 2001. The ECS Agreement was subsequently extended until 3 August 2022. Since 1 January 1979, Canada has had the special status of a Cooperating State within the ESA. By virtue of this accord, the Canadian Space Agency takes part in the ESA's deliberative bodies and decision-making and also in the ESA's programmes and activities. Canadian firms can bid for and receive contracts to work on programmes. The accord has

2706-736: The Vega launcher, Vega-C had its first flight in July 2022. The new evolution of the rocket incorporates a larger first stage booster, the P120C replacing the P80 , an upgraded Zefiro (rocket stage) second stage, and the AVUM+ upper stage. This new variant enables larger single payloads, dual payloads, return missions, and orbital transfer capabilities. Historically, the Ariane family rockets have been funded primarily "with money contributed by ESA governments seeking to participate in

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2772-548: The agency functioned in a de facto fashion. The ESA launched its first major scientific mission in 1975, Cos-B , a space probe monitoring gamma-ray emissions in the universe, which was first worked on by ESRO. The ESA collaborated with NASA on the International Ultraviolet Explorer (IUE), the world's first high-orbit telescope, which was launched in 1978 and operated successfully for 18 years. A number of successful Earth-orbit projects followed, and in 1986

2838-476: The cooperation were laid out in a framework agreement signed by the two entities. On 17 November 2020, ESA signed a memorandum of understanding (MOU) with the South African National Space Agency (SANSA). SANSA CEO Dr. Valanathan Munsami tweeted: "Today saw another landmark event for SANSA with the signing of an MoU with the ESA. This builds on initiatives that we have been discussing for

2904-559: The country eligible for participation in ESA procurements. The country can also participate in all ESA programmes, except for the Basic Technology Research Programme. While the financial contribution of the country concerned increases, it is still much lower than that of a full member state. The agreement is normally followed by a Plan For European Cooperating State (or PECS Charter). This is a 5-year programme of basic research and development activities aimed at improving

2970-572: The exploration of the Moon, the robotic exploration of Mars, leading to a broad Mars Sample Return mission in which Europe should be involved as a full partner, and human missions beyond LEO in the longer term." In August 2019, the ESA and the Australian Space Agency signed a joint statement of intent "to explore deeper cooperation and identify projects in a range of areas including deep space, communications, navigation, remote asset management, data analytics and mission support." Details of

3036-464: The first seismograph in orbit). Later results from the GOCE data exposed details in the Earth's mantle including mantle plumes, ancient subduction zones, and remnants of the Tethys Ocean . Subsequent analysis of GOCE data has also provided new information about the geological makeup of the Antarctic continent, including the detection of ancient continent remnants and at least three cratons beneath

3102-482: The geoid will provide users worldwide with well-defined data product that will lead to: The first Earth global gravity model based on GOCE data was presented at ESA's Living Planet Symposium, in June 2010. Initial results of the GOCE satellite mission were presented at the American Geophysical Union (AGU) 2010 Fall (Autumn) Meeting by Dr Rory Bingham from Newcastle University, UK. The maps produced from

3168-439: The higher rotational velocity of the Earth at the equator compared to near the Earth's poles where rotational velocity approaches zero. Ariane 6 is a heavy lift expendable launch vehicle developed by Arianespace . The Ariane 6 entered into its inaugural flight campaign on 26 April 2024 with the flight conducted on 9 July 2024. Vega is the ESA's carrier for small satellites. Developed by seven ESA members led by Italy . It

3234-458: The issue was almost certainly related to a communication link between the processor module and the telemetry modules of the main computer. The recovery was completed in September 2010: as part of the action plan, the temperature of the floor hosting the computers was raised by some 7 °C (13 °F), resulting in restoration of normal communications. In November 2010, the due completion date for

3300-407: The mantle at mid-ocean ridges produces oceanic crust , and partial melting of the mantle at subduction zones produces continental crust . Mercury has a silicate mantle approximately 490 kilometers (300 miles) thick, constituting only 28% of its mass. Venus 's silicate mantle is approximately 2,800 kilometers (1,700 miles) thick, constituting around 70% of its mass. Mars 's silicate mantle

3366-670: The nation's space industry capacity. At the end of the 5-year period, the country can either begin negotiations to become a full member state or an associated state or sign a new PECS Charter. Many countries, most of which joined the EU in both 2004 and 2007, have started to co-operate with the ESA on various levels: During the Ministerial Meeting in December 2014, ESA ministers approved a resolution calling for discussions to begin with Israel, Australia and South Africa on future association agreements. The ministers noted that "concrete cooperation

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3432-428: The original 20-month mission before it was delayed by the glitches, it was decided to extend the mission lifetime until the end of 2012 in order to complete the original work and carry out a further 18-month mission to improve the collected data. In November 2012 the orbit was lowered from 255 to 235 km (158 to 146 mi) to get higher resolution data, at which time fuel remained for another 50 weeks. In May 2013

3498-873: The other 75%. The ESA has traditionally implemented a policy of "georeturn", where funds that ESA member states provide to the ESA "are returned in the form of contracts to companies in those countries." By 2015, the ESA was an intergovernmental organisation of 22 member states. The 2008 ESA budget amounted to €3.0 billion whilst the 2009 budget amounted to €3.6 billion. The total budget amounted to about €3.7 billion in 2010, €3.99 billion in 2011, €4.02 billion in 2012, €4.28 billion in 2013, €4.10 billion in 2014, €4.43 billion in 2015, €5.25 billion in 2016, €5.75 billion in 2017, €5.60 billion in 2018, €5.72 billion in 2019, €6,68 billion in 2020, €6.49 billion in 2021, €7.15 billion in 2022, €7.46 billion in 2023 and €7.79 billion in 2024. English and French are

3564-526: The protection of space assets", and two further high visibility projects (referred to as inspirators ) an icy moon sample return mission; and human space exploration. In the same year the recruitment process began for the 2022 European Space Agency Astronaut Group . 1 July 2023 saw the launch of the Euclid spacecraft , developed jointly with the Euclid Consortium, after 10 years of planning and building it

3630-475: The right. Countries typically have their own space programmes that differ in how they operate organisationally and financially with the ESA. For example, the French space agency CNES has a total budget of €2,015 million, of which €755 million is paid as direct financial contribution to the ESA. Several space-related projects are joint projects between national space agencies and the ESA (e.g. COROT ). Also,

3696-540: The spacecraft ran out of fuel; deprived of xenon, the ion drive stopped working at 03:16 UTC. On 9 November 2013, a published report indicated that the satellite was expected to re-enter within a day or two. By this date, the perigee altitude had decayed to 155 km (96 mi). On 10 November, ESA expected re-entry to occur between 18:30 and 24:00 UTC that day, with the most probable impact ground swath largely running over ocean and polar regions. Its descending orbit on 11 November 2013 passed over Siberia ,

3762-494: The spacecraft was commissioned and the electrical propulsion system checked for reliability in attitude control . In February 2010 a fault was discovered in the satellite's computer, which meant controllers were forced to switch control to the backup computer. In July 2010, GOCE suffered a serious communications malfunction, when the satellite suddenly failed to downlink scientific data to its receiving stations. Extensive investigations by experts from ESA and industry revealed that

3828-608: The spacecraft while it orbited through the residual air in the thermosphere . The ion propulsion electric engine, designed and built at QinetiQ 's space centre in Farnborough, England, ejected xenon ions at velocities exceeding 40,000 m/s (140,000 km/h; 89,000 mph), which compensated for the orbital decay losses. GOCE's mission ended when the 40 kg (88 lb) xenon fuel tank emptied. The dual Kaufman-type ion thrusters could produce up to 20 millinewtons (0.0045 lbf) of thrust. Although its predicted lifetime

3894-452: The system greatly improved the known accuracy and spatial resolution of the geoid (the theoretical surface of equal gravitational potential on the Earth). The satellite's unique arrow shape and fins helped keep GOCE stable as it flew through the thermosphere at a comparatively low altitude of 255 kilometres (158 mi). Additionally, an ion propulsion system continuously compensated for

3960-438: The two lower liquid fuel stages of the original missile and was equipped with a Briz-KM third stage developed for precise orbit injection. GOCE was launched into a Sun-synchronous dusk-dawn orbit with an inclination of 96.7° and an ascending node at 18:00. Separation from the launcher was at 295 km. The satellite's orbit then decayed over a period of 45 days to an operational altitude, planned at 270 km. During this time,

4026-544: The two main superpowers. In 1958, only months after the Sputnik shock , Edoardo Amaldi (Italy) and Pierre Auger (France), two prominent members of the Western European scientific community, met to discuss the foundation of a common Western European space agency. The meeting was attended by scientific representatives from eight countries. The Western European nations decided to have two agencies: one concerned with developing

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4092-665: The two official languages of the ESA. Additionally, official documents are also provided in German and documents regarding the Spacelab have been also provided in Italian. If found appropriate, the agency may conduct its correspondence in any language of a member state. The following table lists all the member states and adjunct members, their ESA convention ratification dates, and their contributions as of 2024: Previously associated members were Austria, Norway and Finland, all of which later joined

4158-475: The variable deceleration due to air drag without the vibration of a conventional chemically powered rocket engine , thus limiting the errors in gravity gradient measurements caused by non-gravitational forces and restoring the path of the craft as closely as possible to a purely inertial trajectory. After running out of propellant, the satellite began dropping out of orbit and made an uncontrolled re-entry on 11 November 2013. The final gravity map and model of

4224-567: The western Pacific Ocean , the eastern Indian Ocean and Antarctica . The satellite finally disintegrated around 00:16  UTC on 11 November near the Falkland Islands . The satellite's main payload was the Electrostatic Gravity Gradiometer (EGG) to measure the gravity field of Earth . This instrument consisted of three pairs of capacitive accelerometers arranged in three dimensions that responded to tiny variations in

4290-471: Was 20 months, an ESA report in June 2010 suggested that unusually low solar activity (meaning a calmer upper atmosphere, and hence less drag on the craft) meant the fuel would last longer than its predicted 20 months—possibly into 2014. In reality, the end of mission was formally declared on 21 October 2013 after 55 months, with the final 11 months in a lower orbit (with greater air density and therefore greater fuel use). Mantle (geology) A mantle

4356-573: Was founded with the ESA Convention in 1975, when ESRO was merged with ELDO. The ESA had ten founding member states: Belgium , Denmark , France , West Germany , Italy , the Netherlands , Spain , Sweden , Switzerland , and the United Kingdom . These signed the ESA Convention in 1975 and deposited the instruments of ratification by 1980, when the convention came into force. During this interval

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