Satellite crash – live: Out-of-control ERS-2 falls to Earth

The European Space Agency has finally confirmed that the two-tonne satellite reentered the Earth’s atmosphere somewhere between Alaska and Hawaii.

to The Independent’s live coverage of the ERS-2 satellite. Nearly 30 years after it launched, and 13 years after it was decomissioned, the satellite is finally set to return to Earth.

At any point between midday and 9pm GMT on Wednesday (7am to 6pm EST), the space junk could re-enter the Earth’s atmosphere.

While most of it will likely burn up, the European Space Agency (ESA) has warned that there is still a chance of fragments crashing into populated areas.

You can follow all the latest updates right here.

The ERS-2 satellite has been out of service since 2011, having launched from Europe’s Spaceport in French Guiana on 21 April, 1995.

Alongside its sister satellite ERS-1, it has been described as the “grandfathers of Earth observation” in Europe, offering never-before-seen insights into the Earth’s climate and environment.

Both satellites carried a Synthetic Aperture Radar (SAR) and a radar altimeter for studying sea surface temperatures and winds, while the ERS-2 also carried a sensor for atmospheric ozone research.

This gave scientists the ability to monitor the Earth’s protective ozone layer in new ways, while also contributing to our understanding of how climate change is having a significant impact on ocean-surface temperatures.

The latest update from the ESA states that the ERS-2 will re-enter the Earth’s atmosphere at approximately 4.32pm GMT (11.32pm EST) on Wednesday.

This prediction, made using data acquired on 20 February, has an uncertainty of +/- 4.61 hours, meaning it could fall any time between midday and 9pm.

“This uncertainty is due primarily to the influence of unpredictable solar activity, which affects the density of Earth’s atmosphere and therefore the drag experienced by the satellite,” the space agency states.

As the reentry time approaches, the uncertainty window decreases, so we should get an increasingly clear idea of when to expect ERS-2’s arrival as the day progresses.

Just like predicting the time that the ERS-2 satellite will reenter the Earth’s atmosphere, predicting the place also requires a bit of guess work.

The current predicted time of 4.32pm GMT would put the satellite’s reentry over east Africa, as shown by the red marker on this map.

However, given the nine hour window in which it could fall, the satellite could fall along any of those lines, which also cross Europe, North America, Asia and parts of Oceania.

“The ground track passes over a wide range of latitudes due to the nature of ERS-2’s important mission,” the ESA notes on its satellite tracking site.

“ERS-2 was designed to shed light on Earth’s changing climate at a time when humankind’s impact on the environment was not understood as well as it is today. To achieve this, ERS-2 was placed into a ‘Sun-synchronous’ orbit – a type of polar orbit that allowed it to pass over and study a large portion of Earth’s surface.”

The two-tonne ERS-2 satellite is one of the larger pieces of space junk to reenter the Earth’s atmosphere in recent years, meaning it is unlikely that all of it will burn up upon reentry.

The European Space Agency warns that it will break up into fragments around 80 kilometres above the Earth’s surface, with whatever remains then falling across a huge area.

The space agency states: “The vast majority of the satellite will burn up, and any pieces that survive will be spread out somewhat randomly over a ground track on average hundreds of kilometres long and a few tens of kilometres wide.”

None of the fragments that do make it to Earth will contain any toxic or radioactive substances, though there is still potential risk that the projectiles could cause damage or even injury. According to the ESA, this risk is “very, very low”.

It’s hard to calculate exactly how much space junk falls into Earth’s atmosphere each year, though estimates from the US National Oceanic and Atmospheric Administration (NOAA) suggest it is between 200-400 tracked objecs each year.

Some objects are able to enter in a controlled way by using any onboard fuel reserves to aim into the ocean, though satellites like ERS-2 have no such option.

Despite their out-of-control nature, the risk of actually being hit by a piece of space debris falling to Earth is around 1 in 100 billion.

This is:

• ~1.5 million times lower than the risk of being killed in an accident at home
• ~65,000 times lower than the risk of being struck by lightning
• ~three times lower than the risk of being struck by a meteorite

The European Space Agency (ESA) has recalculated the predicted reentry time for the ERS-2 satellite.

ESA scientists now estimate that the satellite will enter the Earth’s atmosphere at 15.49 GMT (10.49 EST), roughly 45 minutes earlier than previously anticipated. The uncertainty window has also narrowed to just +/- 1.76 hours, meaning it could fall any time between 2pm and 5.30pm on Wednesday.

The closer we get to the actual moment of reentry, the more accurate the prediction will be.

Here’s the latest prediction:

The ERS-2 satellite is no longer expected to fall over east Africa, with the ESA’s updated forecast putting its reentry point over the Pacific Ocean. This is where most decommissioned satellites end up when their operators are able to control it, so this would be an ideal spot. Unfortunately, there’s still a big window of error that could see it crash over the US or Europe.

“At the current predicted time of reentry, 15.49 GMT, 21 February, ERS-2 will be located approximately 80 km over the red marker, labelled COIW (centre of impact window),” the update states

“It is here that we currently expect the satellite to begin to break up. The vast majority of the satellite will burn up, and any pieces that survive will be spread out somewhat randomly over a ground track on average hundreds of kilometres long and a few tens of kilometres wide.”

Another update from the European Space Agency has revised the satellite’s expected reentry point to just off the west coast of the US.

This may be the final update before the ERS-2 reentry, the space agency said.