Right now, more than $300 billion worth of satellites are drifting through space in geosynchronous orbit (GEO) — about 22,000 miles from Earth’s surface — but many of these have been “retired” due to normal end of useful life, obsolescence or failure.
In 2011, the Defense Advanced Research Projects Agency (DARPA) initiated a program to recover still-working components from these satellites for reuse in new projects, but recent studies show that active removal of high-mass space debris may be necessary to ensure safe deployment of future satellites.
Retired satellites are typically put into a GEO-disposal or “graveyard” orbit, but the growing number of man-made objects and debris in this low-orbit graveyard is leading to an increased risk of collisions, which in turn threatens to trigger a cascade effect, according to the European Space Agency (ESA).
National Aeronautics and Space Administration (NASA) and ESA studies show that the debris environment can be kept stable, but it requires the removal of around five large objects per year, the agency said.
To accomplish this lofty task, the ESA is looking for companies interested in developing a pioneering mission to retrieve and dispose of dead satellites. The Active Debris Removal mission, known as e.Deorbit, will target high-mass objects first in an effort to clear a safe path into Earth’s orbit.
Key technologies for such space-debris-remediation activities are being developed as part of ESA’s multibranched Clean Space initiative, which aims to reduce the environmental footprint of the space industry both on Earth and off it.
A branch of the initiative is focused on space debris removal, with the agency’s future-oriented General Studies Programme playing a leading role in system studies being conducted in parallel to technology development.
The e.Deorbit study — undertaken at ESA’s Concurrent Design Facility (CDF) in Noordwijk, Netherlands, in 2012 — was the first such system study. A second study began in June this year — also at the CDF — to evaluate debris-capture options.
Advanced robotics technology will also be needed to accomplish the task. One capture concept being explored through ESA studies involves capturing satellites in a net attached to either a flexible tether (as seen in the photo above) or a rigid connection.
While the debris removal program is still in its infancy, the ESA has issued a formal Invitation to Tender for company partners on a predevelopment study — officially beginning the lengthy process.