By Dean Murray
A dead satellite will crash back to Earth next week – and scientists have no idea where it will land.
The best guess by ESA (European Space Agency) for the European Remote Sensing 2 satellite’s (ERS-2) reentry into the atmosphere is Wednesday (21 Feb) at 2:34am.
However, that crash prediction comes with a margin of error some 31 hours either side.
ESA describe the ERS-2 reentry as ‘natural’ as it is no longer possible to control the satellite.
The only force causing ERS-2’s orbit to decay is atmospheric drag, which is influenced by unpredictable solar activity.
ESA say: “While we can forecast the reentry to within a few days, it is not possible to predict exactly when and where the satellite will reenter prior to its final few orbits.
“As we approach the day of reentry, we will be able to predict a time and location with increasing certainty.
“During reentry, the satellite will break up into pieces, the majority of which will burn up. The risks associated with satellite reentries are very low.”
When it launched in April 1995, ERS-2 was the most sophisticated Earth observation spacecraft ever developed in Europe. Together with the almost-identical ERS-1, it collected a wealth of valuable data on Earth’s land surfaces, oceans, and polar caps and was called upon to monitor natural disasters such as severe flooding or earthquakes in remote parts of the world.
In 2011, after almost 16 years of operations, ESA took the decision to bring the mission to an end. A series of deorbiting maneuvers was carried out to lower the satellite’s average altitude and mitigate the risk of collision with other satellites or space debris.
Thirteen years later, the satellite is now reentering the lower layers of Earth’s atmosphere, where it will begin to burn up. As the spacecraft’s reentry is uncontrolled, it is impossible to know exactly when and over which region on Earth this will happen.
ESA’s Space Debris Office is monitoring the satellite as its orbit decays and will provide regular updates in the days leading up to reentry.
“The ERS-2 satellite, together with its predecessor ERS-1, changed our view of the world in which we live,” says Mirko Albani, Head of ESA’s Heritage Space Program.
“It provided us with new insights on our planet, the chemistry of our atmosphere, the behavior of our oceans, and the effects of humankind’s activity on our environment.”
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