GOCE reentry – live


This is a live report of the GOCE satellite reentry into the Earth’s atmosphere. (Update: GOCE was destroyed around 0:00 UT on the night between 10th and 11th of November 2013)

11th November 2013, 20:26 UT
A photograph of GOCE burning in the atmosphere has been just released. This photo was taken on 00:20 UT from Falkland Islands and present a long streak with a central wider area. The photograph is shown in the gallery of this article. The author of this photo is Bill Chater.

11th November 2013, 11:40 UT
ESA states that GOCE reentered the Earth’s atmosphere no later than 00:16 UT, which corresponds to a geographical location of 60 degree West and 56 degree South, east from the southern tip of Argentina. This means that the debris of GOCE likely sank in the waters of south Atlantic Ocean.

11th November 2013, 09:52 UT
How big was GOCE? It was a relatively small satellite, weighting 1077 kg at launch. There are smaller satellites than GOCE (“microsats” or “nanosats”), which can weight as little as 1 kg. There are also satellites much bigger than GOCE – for example a typical weight of a telecommunication satellite placed on geostationary orbit is between 3 and 5 tons.
The International Space Station (ISS), which is the biggest object on orbit, weights more than 400 tons. In about 10 to 15 years from now the lifetime of ISS will be over and it will have to be safely deorbited. The reentry of ISS will have to be carefully guided and will have to take place over unpopulated regions of Earth, probably over the Pacific Ocean.

11th November 2013, 09:22 UT
ESA states that GOCE was destroyed around 0:00 UT. At that time GOCE was on orbit above Siberia, western Pacific, eastern Indian Ocean and Antarctica. No damage from GOCE’s debris has been reported.
Each year approximately 100-150 tonnes of man-made hardware falls from the orbit to the Earth. This value is very small in comparison to nature: it is estimated that between 35 and 80 thousand tonnes of meteorites enter the atmosphere every year. Thus, the risk of injury from falling man-made objects is minimal.

11th November 2013, 01:02 UT
The reentry window calculated on the last data sent by GOCE has just passed. It is almost certain that GOCE has already burned in the atmosphere. The event has probably taken place over an unpopulated area.
There were no sightings or communications with GOCE since shortly after 23:10 UT. The last data from GOCE indicated a rising temperature, which at that time has exceeded 80 degrees Celsius at the onboard computer and at the batteries. It is probable that shortly after the last communication session GOCE ceased to function, either due to fragmentation of its structure or rising temperature.
In few hours an official ESA release will be published. By that time it should be known where GOCE has burned in the atmosphere.

11th November 2013, 00:30 UT
In 20 minutes the reentry window for GOCE will expire. It is probable that GOCE has already burned in the atmosphere away from the land or populated places and was unnoticed.

10th November 2013, 23:46 UT
ESA expects no further contact with GOCE. This satellite might be already destroyed, but may be still on orbit.

10th November 2013, 23:35 UT
It is close to the middle of reentry window for GOCE. It is possible that GOCE has already burned in the atmosphere. The confirmation of GOCE’s destruction might take at least an hour.

10th November 2013, 23:22 UT
ESA reports: Contact with GOCE was made once again from the Troll station in Antarctica. The central computer temperature is at 80ºC and the battery is at 84ºC. At an altitude of less than 120 km, the spacecraft is – against expectations – still functional.

10th November 2013, 22:55 UT
GOCE again established a short communication session with a ground station. Currently the satellite is on orbit at an altitude of 117 x 128 km. This might be its final orbit.

10th November 2013, 22:31 UT
ESA predicts that GOCE will reenter the atmosphere sometime between 22:50 and 00:50 UT.

10th November 2013, 21:41 UT
GOCE made a successful communication session with a ground station in Antarctica at 21:16 UT. The temperature of the onboard computer and battery is at 64 degrees Celsius and a few parts of that computer are already over 80 degrees Celsius. 
The current reentry prediction completely eliminates the destruction chance over Europe and almost completely over Africa. Reentry is possible above the Atlantic Ocean, polar regions, both South and North America, Asia, Australia, New Zealand, Indian Ocean and the Pacific Ocean.

10th November 2013, 21:22 UT
ESA estimates that GOCE will reenter the atmosphere between 22:30 and 00:30 UT.

10th November 2013, 20:48 UT
GOCE contacted the ground station in Antarctica at 19:50 UT. The temperature of the onboard computer (located near to the front of the satellite) has risen to 54 degrees Celsius. The next communication session is planned at around 21:25 UT.

10th November 2013, 20:18 UT
During the communication session before 19:00 UT, GOCE was at altitude of 126 km. Later, around 19:50 UT there was another session planned, this time using a ground station in Antarctica. Right now there is no confirmation if that session was successful.

10th November 2013, 19:16 UT
Just before 19:00 UT there was a successful communication with GOCE. This means that the satellite is still circling around the Earth.

10th November 2013, 18:19 UT
ESA plans the next communication session with GOCE at around 19:00 UT.

10th November 2013, 17:13 UT
Around 16:30 UT the GOCE orbit was calculated to be around 131 x 142 km. The orbital decay process is now 1,5 km per hour and the rate is increasing.

10th November 2013, 15:52 UT
The first instruments of GOCE are switched off. The onboard computer’s temperature is approximately 40 degree Celsius. The spacecraft is still in good condition and at 14:37 UT there was a communication session with a ground station.

10th November 2013, 14:48 UT
As of 14:30 UT the GOCE  orbit was calculated to be around 135 x 145 km.

10th November 2013, 13:42 UT
The Inter-Agency Space Debris Coordination Committee predicts the GOCE’s reentry to occur between 18:30 UT – 24:00 UT. According to these calculations, the destructive reentry will probably happen either above oceans or polar regions. Reentry above Europe is very unlikely.

10th November 2013, 10:30 UT
GOCE is now on a 139 x 147 km orbit. This orbit is decreasing at a rate of 1 km per hour. The atmospheric drag became too large to be measured by the onboard accelerometers and calculations suggest the average value to be around 165 mN. The satellite is still functioning, however the temperature of onboard instruments has significantly risen over the last day.

10th November 2013, 10:25 UT
So far no reports have been published from observations of previous GOCE passes above Australia and Tasmania. The next opportunity for more visual observations will come in about 3 hours, when GOCE will be passing above northern Canada.

10th November 2013, 09:10 UT
Most predictions suggest that GOCE is still on orbit, although these are the last hours of the satellite before its destructive reenetry. At this stage positive or negative reports from observers from all around the World are important, because the exact reentry moment is not known and is calculated with a margin of several hours.

10th November 2013, 00:50 UT
The European Space Agency (ESA) has published a dedicated website, on which the current postion of GOCE is presented.

9th November 2013, 23:00 UT
At 23:00 UT, the GOCE orbit is calculated to be just 149×158 km.

9th November 2013, 21:40 UT
Some reentry predictions suggests that GOCE will be destroyed on the 10th of November, around 15 UT plus minus 17 hours. This means that we are already inside the “reentry window”, where deorbitation is possible.

9th November 2013, 17:00 UT
This is the beginning of our live report of the GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) reentry into the Earth’s atmosphere. The reentry will end in the destruction of GOCE, but up to 250 kg of debris could impact the surface or sink in the oceans.

As of the 9th of November, 17:00 Universal Time (UT), the satellite is on orbit. Several observations have been reported from various locations around the World. At 16:00 UT the satellite’s orbit was about 152 x 162 km and it was decreasing rapidly. Reentry could happen anytime after 21:00 UT of the 9th of November, probably in the early afternoon of the 10th of November.

This live report will be updated as soon as new information becomes available.

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GOCE / Credits - ESA


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