Dead European satellite weighing 2,000 kg will crash back to Earth this week – but experts still don’t know exactly where it will land
It has been floating above our planet for almost 30 years.
But a European Space Agency (ESA) satellite will finally crash back into Earth this week.
Launched from French Guiana in 1995, ERS-2 weighs just over 2,000kg – about the same as an adult rhino.
ESA estimates it will enter Earth’s atmosphere on Wednesday (February 21) at 11:14 GMT (12:14 CET).
Although experts have no idea where it will land, ESA says the annual risk of a human being even injured by space debris is about one in 100 billion.
Artistic illustration of the European Remote Sensing 2 (ERS-2) satellite in space. It is finally returning to Earth after ending its activities more than a decade ago
Image of ERS-2 captured from space by HEO, an Australian company with an office in Britain, taken by other satellites between January 14 and February 3. It shows ERS-2 as it rotates on its journey back to Earth. The British agency says they have been shared with ESA to help track the return of ERS-2
ESA said there is a degree of uncertainty in its 3 p.m. return forecast.
This means it could re-enter on Wednesday 3pm either side of 11:14 GMT – although 11:14 GMT is the agency’s best estimate.
“This uncertainty is mainly due to the influence of unpredictable solar activity, which affects the density of the Earth’s atmosphere and thus the drag experienced by the satellite,” the report said in a statement.
ESA said it is monitoring the satellite “very closely”, along with international partners, and providing regular updates on a special web page.
The ERS-2 satellite was launched on April 21, 1995 from ESA’s Guyana Space Center near Kourou, French Guiana, to study Earth’s land surfaces, oceans and polar caps.
After fifteen years, the spacecraft was still functioning when ESA declared the mission complete in 2011.
After the deorbitation maneuvers used up the satellite’s remaining fuel, ground control experts began lowering the altitude from about 785 km to 573 km.
At the time, experts wanted to minimize the risk of collisions with other satellites or increase the cloud of “space junk” currently orbiting our planet.
Since then, ERS-2 has been in a period of ‘orbital decay’, meaning it is gradually getting closer and closer to Earth as it orbits the planet.
ERS-2 satellite before launch. ERS-2 was launched in 1995, succeeding its sister, the first European Remote Sensing satellite ERS-1, which was launched in 1991. The two satellites were designed as identical twins with one key difference: ERS-2 included an additional instrument to monitor ozone levels in the atmosphere
The ERS-2 satellite was launched in April 1995 from ESA’s Guyana Space Center near Kourou, French Guiana (pictured)
ERS-2 will re-enter Earth’s atmosphere and burn up once its altitude decreases to about 50 miles (80 km) – about a fifth of the distance of the International Space Station.
At this altitude it will break into fragments, the vast majority of which will burn up in the atmosphere.
However, some fragments could reach the Earth’s surface, where they will “most likely fall into the ocean,” according to ESA.
“None of these fragments will contain toxic or radioactive materials,” the agency said.
While ESA cannot guarantee that there is no chance of ERS-2 hitting anyone, ESA has indicated that the annual risk of even one human being injured by space debris is less than one in 100 billion.
That is about 1.5 million times lower than the risk of dying at home in an accident and 65,000 times lower than the risk of being struck by lightning.
Worryingly, ESA describes the event as a ‘natural’ reentry, as ground crews cannot control the event during descent.
“ERS-2 consumed the last of its fuel in 2011 to minimize the risk of a catastrophic explosion that could have created a large amount of space debris,” the agency said.
‘The batteries were dead and the communications antenna and electronics on board were disabled.
Illustrated timeline of the European Remote Sensing 2 (ERS-2) satellite’s mission provided by the ESA, which estimates it will enter Earth’s atmosphere on Wednesday (21 February) at 11:14 GMT (12:14 CET) intrude
This was the last image of ERS-2 captured over Rome, Italy on July 4, 2011. Shortly afterwards, maneuvers began to deorbit the veteran satellite. Flight operations ended on September 5, 2011
“There is no longer a way to actively control the movement of the satellite from the ground during its descent.”
ERS-2 was launched in 1995 as a follow-up to its sister satellite, ERS-1, which had been launched four years earlier.
Both satellites were equipped with the latest high-tech instruments, including a radar altimeter (which sends pulses of radio waves to the ground) and powerful sensors to measure ocean surface temperatures and offshore winds.
ERS-2 had an additional sensor to measure the ozone content of our planet’s atmosphere, which is important for blocking radiation from the sun.
ERS-1 is no longer operational due to a malfunction in 2000, but its exact location is unknown.
WHAT IS SPACE JUNK? MORE THAN 170 MILLION DEAD SATELLITES, SPENT MISSILES AND PAINT FLAKES ARE A ‘THREAT’ TO THE SPACE INDUSTRY
There are an estimated 170 million pieces of so-called “space junk” — left behind from missions that can be as large as used rocket stages or as small as paint flakes — in orbit, along with about $700 billion in space infrastructure. .
But only 27,000 are tracked, and because the fragments can reach speeds of over 27,000 kilometers per hour, even small pieces can seriously damage or destroy satellites.
However, traditional gripping methods don’t work in space because suction cups don’t function in a vacuum and temperatures are too cold for substances like tape and glue.
Magnet-based grabs are useless because most of the debris in orbit around Earth is not magnetic.
Our planet is currently orbiting around 500,000 man-made debris (artist’s impression), consisting of disused satellites, bits of spacecraft and spent rockets.
Most proposed solutions, including debris harpoons, require or cause a forceful interaction with the debris, which can push these objects in unintended, unpredictable directions.
Scientists point to two events that have seriously exacerbated the space debris problem.
The first occurred in February 2009, when an Iridium telecom satellite and Kosmos-2251, a Russian military satellite, accidentally collided.
The second was in January 2007, when China tested an anti-satellite weapon on an old Fengyun weather satellite.
Experts also pointed to two sites that have become worryingly messy.
One of these is low Earth orbit, which is used by navigation satellites, the ISS, China’s manned missions and the Hubble telescope, among others.
The other is in geostationary orbit and is used by communications, weather and surveillance satellites that must maintain a fixed position relative to Earth.