OTD in Space - Nov. 10: Europe’s GOCE Satellite Falls from Space
On November 10, 2013, Europe's GOCE satellite fell to Earth. GOCE is short for Gravity field and steady-state Ocean Circulation Explorer. Its mission was to map Earth's gravitational field. GOCE did this for four years. Then it ran out of fuel. Controllers weren't sure where it would fall back to Earth or linger in orbit. Some people worried that GOCE might crash into a populated area. However, the small spacecraft broke up in the atmosphere and didn't cause any property damage. It disintegrated about 50 miles above the Falkland Islands in the South Atlantic Ocean. The European Space Agency called the mission a success. GOCE lasted far longer than expected. It showed small variations in Earth's gravity, mapped the structure of Earth's crust and mantle, and tracked ocean currents.
Goce gravity map traces ocean circulation
Scientists have produced what they say is the most accurate space view yet of global ocean currents and the speed at which they move. The information has been drawn from a range of satellites, but in particular from the European Space Agency's Goce mission. This platform, which operated from 2009 to 2013, made ultra-precise measurements of Earth's gravity. It has detailed the role this force plays in driving ocean circulation. The new model - presented at a Goce conference at the Unesco HQ in Paris, France - will be of fundamental importance to climate modellers, because it is the mass movement of water that helps to transport heat around the globe. Goce carried instrumentation capable of sensing very subtle changes in Earth's gravitational tug. This pull varies ever so slightly from place to place because of the uneven distribution of mass inside the planet. Scientists used these observations to construct what is called a "geoid", which essentially describes the "level surface" on an idealised world. It is the shape the oceans would adopt if there were no winds, no currents and no tides to disturb them. By comparing this geoid with measurements of sea-surface height made by other spacecraft, researchers can see where water has become piled up. And it is water's desire always to "run downhill" that is a major influence on the direction and speed of currents - although atmospheric winds and the Earth's rotation are of course critical partners in the overall picture. Clearly visible in the map at the top of this page are the Agulhas Current flowing down the African coast; the Gulf Stream running across the Atlantic; the Kuroshio Current that sweeps south of Japan and out into the North Pacific; as well as the Antarctic Circumpolar Current, and the system of currents that hug the Equator. In places, these great trains of water move in excess of 1m per second. The new Goce model of ocean circulation has been checked and integrated with the point measurements from drifting buoys. This has helped capture some of the smaller-scale features in the currents that lie beyond the capabilities of satellites, even one that made as highly resolved observations as the Esa mission. "Goce has really made a breakthrough for the estimation of ocean currents," said Marie-Helene Rio from the Italian National Research Council's Institute of Atmospheric Sciences and Climate. "The mission objective in terms of geoid [measurement] has been achieved at 1-2cm accuracy at 100km resolution, and in terms of ocean currents this translates into an error that is less than 4cm/s." Scientists can now add in data collected about sea temperature to calculate the amount of energy the oceans move around the Earth. Computer models that try to forecast future climate behaviour have to incorporate such details if they are to run more realistic simulations. The 5th International Goce User Workshop this week will be looking at the many other applications that came out of the satellite's mission. Mapping gravity variations can yield information about ice mass loss in the Antarctic, and the deep-Earth movements that give rise to great quakes. Goce was dubbed the "Ferrari of space" because of its sleek looks and the fact that it was assembled in Italy. When operational, it was the lowest flying scientific satellite in the sky, making observations at an altitude of just 224km during its late phases. This allowed the spacecraft to better sense the tiny gravity variations, but meant it had to constantly thrust an electric engine to stay aloft. When the xenon fuel for this engine was exhausted in November 2013, Goce succumbed to the force it had been sent up to study and fell back to Earth. Eyewitnesses saw surviving debris fall into the South Atlantic, just off the tip of South America, south of the Falkland Islands.
GOCE senses changing gravity
The animation, based on measurements from ESA’s GOCE satellite and the NASA–German Grace mission, shows that ice lost from West Antarctica has caused a dip in Earth’s gravity. GOCE was not designed to show changes in gravity over time. However, high-resolution gravity gradients that GOCE measured over Antarctica between November 2009 and June 2012 were analysed by scientists from the German Geodetic Research Institute, Delft University of Technology in the Netherlands, the Jet Propulsion Lab in USA and the Technical University of Munich in Germany and reveal that ice lost during this period left its signature in Earth’s gravity. The GOCE data complement those of the Grace mission, which was designed to show change but offers coarser resolution data than GOCE. This has allowed datasets from both gravity missions to be combined, offering even greater insight into the dynamics of Antarctica’s different basins. Credits: ESA/DGFI/Planetary visions
GOCE reentering the atmosphere
Video footage of GOCE reentering the atmosphere taken by Bill Chater in the Falklands at 21:20 local time on 11 November 2013. After more than four years mapping Earth's gravity with unrivalled precision, the GOCE mission came to a natural end when it ran out of fuel on 21 October.
GOCE Satellite Crashes Back to Earth
The European Space Agency said the GOCE caused no damage after re-entering the Earth's atmosphere Monday morning.
GOCE Satellite - Science Performed Before Its Destruction | Video
ESA's Gravity field and steady-state Ocean Circulation Explorer (GOCE) mapped the Earth's gravity with precision. Find out about the science it performed in this end of mission video.
Europe's global mapping satellite on crash course for Earth...but where?
A satellite which has been mapping the world's gravitational field and ocean circulation is failing... euronews, the most watched news channel in Europe
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A satellite which has been mapping the world's gravitational field and ocean circulation is failing and on a crash course for Earth. The European Space agency's GOCE satellite has been in a low-Earth orbit Since 2009. The ESA says it cannot predict how quickly or where exactly the one-tonne spacecraft will crash. Most of it will burn up when it hits the earth's atmosphere, thought to be around Sunday. "In total since Sputnik was launched about 15,000 tons have returned from space" the ESA's Head of Space Debris, Heiner Klinkrad said, adding "typically between 10 and 40 percent of the initial mass survives such a re-entry. Velocity upon impact is between 200 and 300 hundred kilometres an hour, which is a speed that you can achieve on German motorways with a good-sized car," This may be one of the last crashes of its type, as an international agreement now means satellites must be directional on re-entry to allow them to be crashed harmlessly into the ocean. Find us on:
Countdown on for Satellite to Crash to Earth
The European Space Agency (ESA) has said its GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) research satellite will crash to Earth on Sunday night or during the day on Monday, but debris is unlikely to cause any casualties. (Nov. 8) The Associated Press is the essential global news network, delivering fast, unbiased news from every corner of the world to all media platforms and formats.
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ESA's GOCE gravity-mapping satellite to fall to Earth next month
Originally published on September 26, 2013 The European Space Agency's GOCE satellite will fall back to Earth next month after nearly five years gathering data on the Earth's gravitational field. The $450 million GOCE satellite was launched in 2009 with the mission of creating the most accurate and detailed model of the Earth's gravitational field yet, known as a geoid. The GOCE's position in relation to Earth is measured by GPS tools and this data helps develop a map of of the planet's gravitational field. Onboard instruments which detect tiny variations in the Earth's gravitational pull help complete the picture. The spacecraft is the lowest-orbiting satellite in history: at just 254 km above the Earth it comes very close to the lowest safe orbital altitude. The satellite will begin falling Earthward from a height of 224 km when it exhausts its fuel in mid-October.Most of the satellite is expected to disintegrate in the atmosphere during its descent. The data provided by GOCE will allow scientists to better understand global ocean circulation system and the behaviour of tectonic plates in earthquake zones, among numerous other applications. -------------------------------------------------------- TomoNews is your daily source for top animated news. We've combined animation and video footage with a snarky personality to bring you the biggest and best stories from around the world. For news that's fun and never boring, visit our channel:
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Pulling together: How gravity shapes Planet Earth - Space
Gravity is one of the fundamental forces of nature, its invisible grip governing our planet - from the rocks inside to the seas on the surface. However, getting a grip on gravity on a global scale can only be done from space, and that's something ESA's GOCE satellite mission has been doing since 2009. One of the ultimate goals of GOCE is to improve our knowledge of the geoid, a kind of 'gravity map' of the planet, that is essential for oceanographers, surveyors, engineers and Earth-science researchers. euronews knowledge brings you a fresh mix of the world's most interesting know-hows, directly from Space and Sci-Tech experts. Subscribe for your dose of space (Mondays) and sci-tech (Wednesdays): http://eurone.ws/Y9QTy3 Made by euronews, the most watched news channel in Europe, euronews knowledge gives YouTubers amazing access into the scientists labs and research fields, including gravity field! [photo credit Flickr/woodleywonderworks: http://www.flickr.com/photos/wwworks/]
Gravity Ocean Circulation Explorer
Satellites map changes in Earth's surface caused by earthquakes but never before have sound waves from a quake been sensed directly in space -- until now. ESA's hyper-sensitive GOCE gravity satellite has added yet another first to its list of successes. Earthquakes not only create seismic waves that travel through Earth's interior, but large quakes also cause the surface of the planet to vibrate like a drum. This produces sound waves that travel upwards through the atmosphere. The size of these waves changes from centimetres at the surface to kilometres in the thin atmosphere at altitudes of 200--300 km. Only low-frequency sound -- infrasound -- reaches these heights. It causes vertical movements that expand and contract the atmosphere by accelerating air particles. On Monday, Japan remembers the 20 000 people who died in the earthquake and tsunami that devastated its northeastern coast two years ago. New studies have revealed that this massive quake was also felt in space by ESA's GOCE satellite. Since it was launched in 2009, GOCE has been mapping Earth's gravity with unrivalled precision, orbiting at the lowest altitude of any observation satellite. But at less than 270 km up, it has to cope with air drag as it cuts through the remnants of the atmosphere. The cleverly designed satellite carries an innovative ion engine that instantly compensates for any drag by generating carefully calculated thrusts. These measurements are provided by very precise accelerometers. While the measurements ensure that GOCE remains ultra-stable in its low orbit to collect ultra-precise measurements of Earth's gravity, atmospheric density and vertical winds along its path can be inferred from the thruster and accelerometer data. Exploiting GOCE data to the maximum, scientists from the Research Institute in Astrophysics and Planetology in France, the French space agency CNES, the Institute of Earth Physics of Paris and Delft University of Technology in the Netherlands, supported by ESA's Earth Observation Support to Science Element, have been studying past measurements. They discovered that GOCE detected sound waves from the massive earthquake that hit Japan on 11 March 2011. When GOCE passed through these waves, its accelerometers sensed the vertical displacements of the surrounding atmosphere in a way similar to seismometers on the surface of Earth. Wave-like variations in air density were also observed. When GOCE passed through these waves, its accelerometers sensed the vertical displacements of the surrounding atmosphere in a way similar to seismometers on the surface of Earth. Wave-like variations in air density were also observed.
Gravity's grip on earth
http://www.euronews.com/ Gravity is one of the fundamental forces of nature, its invisible grip governing our planet - from the rocks inside to the seas on the surface. In this edition of Space, we begin our adventure in a massive cave in northern Italy, a space beneath the surface of the Earth that is so big it has an effect on the local gravity field. If you parked a car weighing one tonne above this cave, it would weigh five grammes less than elsewhere. However, getting a grip on gravity on a global scale can only be done from space, and that's something ESA's GOCE satellite mission has been doing since 2009. One of the ultimate goals of GOCE is to improve our knowledge of the geoid, a kind of 'gravity map' of the planet, that is essential for oceanographers, surveyors, engineers and Earth-science researchers. Also tracking invaluable information about the Earth's gravity field is the GRACE mission. While this pair of satellites don't have the high precision of other missions, they offer something unique: a monthly survey of the gravity field. This US-German mission has been tracking the loss of ice mass over Greenland for the past decade, offering useful evidence for those studying climate change. Find us on:
Earth Has Herky-Jerky Gravity
Orbiting our planet, spacecraft really take their lumps and bumps. Europe's GOCE satellite has produced the most detailed map of the Earth's gravitational field, helping scientists understand ocean circulation and its effects on climate change. Credit: ESA
Launched on 17 March 2009, ESA's Gravity field and steady-state Ocean Circulation Explorer (GOCE) is bringing about a whole new level of understanding of one of Earth's most fundamental forces of nature: the gravity field. Dubbed the 'Formula 1' of satellites, GOCE is mapping Earth's gravity field in unprecedented detail. This has given rise to a unique model of the 'geoid', which is the surface of an hypothetical global ocean in the absence of tides and currents, shaped only by gravity. It is a crucial reference for measuring ocean circulation and sea-level change, which are affected by climate change. The colours in the image represent deviations in height ( -100 m to + 100 m) from an ideal geoid. The blue colours represent low values and the reds/yellows represent high values. See also: Earth's gravity revealed in unprecedented detail at: http://www.esa.int/esaCP/SEM1AK6UPLG_index_0.html
GOCE Reveals Earth's gravity in unprecedented detail
After just two years in orbit, ESA's GOCE satellite has gathered enough data to map Earth's gravity with unrivalled precision. Scientists now have access to the most accurate model of the 'geoid' ever produced to further our understanding of how Earth works.
Geoid based on only two months of GOCE data
The first geoid based on only two months of GOCE data, from November and December 2009, shows the excellent capability of the satellite to map tiny variations in Earth's gravity. The geoid is the shape of an imaginary global ocean dictated by gravity in the absence of tides and currents. It is a crucial reference for accurately measuring ocean circulation, sea-level change and ice dynamics -- all affected by climate change. An accurate model of the geoid is also important for surveying and geodesy, and for studying Earth interior processes. Credits: ESA Reference article: http://www.esa.int/esaCP/SEMQC9VTLKG_index_0.html Source: http://download.esa.int/qt/Geoid-Animation-InfinityLight.mov
Gravity Ocean Circulation Explorer
The first geoid based on only two months of GOCE data, from November and December 2009, shows the excellent capability of the satellite to map tiny variations in Earth's gravity. The geoid is the shape of an imaginary global ocean dictated by gravity in the absence of tides and currents. It is a crucial reference for accurately measuring ocean circulation, sea-level change and ice dynamics -- all affected by climate change.
GOCE launch highlights: The 'magic moment' of a launch
Lauching a satellite is a risky business, and ESA's GOCE Project Manager Danilo Muzi describes how it feels at this exciting stage of the mission preparations.
GOCE launch highlights: The launch
The tension builds in the seconds before rocket ignition and lift-off... and then everything seems to happen at once. Mission controllers monitor the progress of GOCE in the crucial minutes after launch, and then celebrate!
Gravity Ocean Circulation Explorer
The Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite developed by the European Space Agency (ESA) was lofted into a near-Sun-synchronous, low Earth orbit by a Rockot launcher lifting off from the Plesetsk cosmodrome in northern Russia. The Russian Rockot launcher, derived from a converted ballistic missile, lifted off at 15:21 CET (14:21 GMT) and flew northward over the Arctic. About 90 minutes later, after one orbital revolution and two Breeze-KM upper-stage burns, the 1052 kg spacecraft was successfully released into a circular polar orbit at 280 km altitude with 96.7º inclination to the Equator. The launch was procured from Eurockot Launch Services, a German/Russian company based in Bremen, Germany.