With approximately 27,000 pieces of space debris orbiting the Earth, the European Space Agency has declared an urgency to take them out and protect our planet and crucial communications satellites.  How do they plan to do this?  Weapons of choice vary from nets and harpoons, to suicide robots.

Future debris density at poles with and without active debris removal

Future space 'cleaning' missions are being plannned, with a wide variety of this insane-sounding ideas proposed such as a Star Trek-style tractor beam, all to aid in the protection of $100 billion worth of satellites orbiting Earth.

Heiner Klinkrad, head of ESA's Space Debris Office, spoke at the 6th European Conference on Space Debris, comparing the agency's understand and urgency of solving this problem to the need to deal with climate change 20 years ago.

"Whatever we do is going to be an expensive solution," Klinkrad said. "But one has to compare the costs of what we are investing to solve the problem as compared to losing the infrastructure that we have in orbit."

Experts estimate that about 27,000 objects measuring 10 centimeters (4 inches) or more are flying through orbit at 80 times the speed of a passenger jet.  So many proposals were made to combat this.  

Thomas Schildknecht, an astronomer at the University of Bern, Switzerland, said it would be technically feasible to send a satellite into space to capture objects with a net and harpoon.  For anything bigger, a dedicated robot could be built which would to go on a suicide mission, valiantly sacrificing itself to bring the satellite down safely. Such missions could cost up to $200 million each.  

"I'm confident that we will see demonstration missions in the near future," said Schildknecht.

Klinkrad said 5-10 large objects need to be collected each year for this mission to be successful, otherwise we could be facing what is known as the Kessler Syndrome.  Simply put, a few major collisions would trigger a cascade effect, massively increasing the amount of dangerous debris in orbit.  Kind of like when the proverbial excrement hits the fan; but instead of feces...it's space debris.

This Clean Space initiative will be commencing soon, maturing technology to approach, capture and deorbit targets.  The mission is already under study.