The European GOCE satellite will reenter Earth’s atmosphere in just a few days. This is going to be the first uncontrolled reentry of an European Space Agency satellite since 1987.
Information published on the ESA webiste suggests that around 25% of GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) will survive the destructive plunge into the atmosphere. As much as 250 kg of pieces of the satellite should survive the destruction and hit the Earth.
On the last possible moment the satellite will be passivated. This means the removal of the onboard fuel rest and turning off the transmitters, so that GOCE will not interfere with other satellites.
At the moment of writing this article (4th of November, 21:00 Central European Time, CET), it is predicted that GOCE will be destroyed around the 10th of November, around 10 am CET. The exact reentry time is still uncertain.
In the morning hours of the 4th of November, GOCE’s orbit had a mean altitude of 192 km. During this day the satellite is predicted to loose an additional 4 km of altitude. To sum up, it is over 30 km of decay since the 21st of October, when the satellite’s ion engine was turned off and GOCE began falling towards the Earth. Currently, the atmospheric drag on the satellite is 24 mN with peaks of 35 mN. In October, it was just 8 mN.
The initial orbit of GOCE was around 280 km, which was later gradually lowered. The final working orbit of 230×220 km was maintained until the 21st of October. On this day the GOCE ion engine was depleted. Since that time the satellite is sinking in the atmosphere and will end in a destructive reentry.