The European Space Agency says it is studying the possibility of a future mission to capture derelict satellites adrift in orbit around the Earth.

The e.DeOrbit mission under study the ESA's Clean Space Initiative, would aim to snag and collect orbiting junk to reduce the environmental impact of the space industry on Earth and space alike, the agency said in a release issued from its Paris headquarters Friday.

Decades of launches have left Earth surrounded by a halo of space junk, with more than 17,000 trackable objects larger than a coffee cup that could threaten working missions with catastrophic collision, ESA scientists said.

The only way to control the debris field across key low orbits is to remove large items such as derelict satellites and launcher upper stages, they said.

The first technical challenge such a mission would face is to safely approach a drifting object left in an uncertain state; then capture it and guide the combined satellite and salvage craft down for a controlled burn-up in the atmosphere.

Several capture mechanisms are being studied, the ESA said, including throw-nets, clamping mechanisms and harpoons.

A symposium in the Netherlands in May will cover studies and technology developments related to e.DeOrbit, the ESA said.