Planet Earth. Image: Fiore/Shutterstock
Space debris circling our planet has doubled in just 25 years, with more litter to come. Scientists are more worried than ever.
“We are very much concerned.” That was the message from Rolf Densing, director of operations at European Space Agency (ESA), at a special conference that runs throughout this week to discuss space debris.
The estimate of how many pieces of debris – left from old, disused or damaged satellites in our upper atmosphere – is around 150m.
Dangerous
Some bits are large, some are small, but every single one is potentially dangerous to any space mission.
Regardless of size, these objects can travel at speeds up to 28,000kph, potentially ripping through or (at the very least) damaging the surface of satellites or, worse still, crewed spacecraft.
In 1993, scientists were aware of 8,000 human-made objects in orbit that were larger than 10cm – these being of significant concern.
By 2015, the ESA had revised that figure up to 12,000. However, that now seems a gross miscalculation after scientists revealed yesterday that there around 20,000 objects of this size orbiting our planet.
According to Holger Krag, who works at ESA’s space debris office, there are around 5,000 objects larger than 1 metre in diameter, “roughly 20,000 objects with sizes over 10cm … and 750,000 ‘flying bullets’ of around 1cm.
“For objects larger than 1mm, 150m is our model estimate for that.”
The risk of impact is relatively remote, though not as remote as it was 20, 10 or even five years ago, given the significant rise in these weapons.
Satellite crash
Yesterday, a report from a UK scientist warned against plans by numerous tech giants to litter our atmosphere with thousands of communications satellites.
These will, it is hoped, provide internet access to the entire planet.
But according to Dr Hugh Lewis, a senior lecturer in aerospace engineering at the University of Southampton, these projects advocated by Google, Samsung and SpaceX could cause significant problems.
Lewis ran a 200-year simulation to assess the possible consequences of such a rise in orbital traffic, according to The Guardian. He found that it could create a 50pc increase in the number of catastrophic collisions between satellites.
These crashes would, in turn, add more and more items of space debris, meaning that ESA’s measurements are going to need some fine tuning in years to come.
Impact
“The constellations that are due to be deployed from next year contain an unprecedented number of satellites, and a constellation launched without much thought will see a significant impact on the space environment because of the increased rate of collisions that might occur,” Lewis said.
According to AFP, the trash currently circling our planet ranges from fuel tanks and Soviet-era nuclear-powered satellites – dripping sodium and potassium coolant from decrepit hulls – to nuts, bolts and tools dropped by spacewalking astronauts.
The items ironically include a 1.5-metre debris shield that floated off as it was being installed on the International Space Station on March 30. Lost in low orbit, the shield will eventually be sucked into Earth’s atmosphere and burn up.
In 2015, programmer James Yoder created ‘Stuff In Space’, a website that uses orbital data obtained from Space-Track.org and a JavaScript library called satellite.js to calculate satellite positions.
