The European Space Agency, or ESA, said it successfully tested a prototype radar system in Santorcaz, a town located 30 kilometers (18 miles) outside Madrid, designed to find space junk that could damage military, commercial and civilian satellites.

"This new sensor - active since last November - has key technologies for detecting low-orbit space debris and marks an important step toward operational radars," the ESA said in a statement.

The prototype detected "objects of around one meter" and represents progress in refining the technology it uses, but its current results would be insufficient for developing any eventual detection system for objects with a size of about 10 centimeters, the ESA said.

Spain's Indra Espacio and Germany's Fraunhofer Institute for High Frequency Physics and Radar Techniques, or FHR, received a contract worth 4.7 million euros ($6.4 million) in 2010 to develop the system.

The project uses a monostatic radar base, a system that has only one station that emits electromagnetic energy at a target and then analyzes the signal it receives.

The ESA awarded a contract for a similar system last year to France's ONERA and five industrial partners from Spain, France and Switzerland.

The system being developed by ONERA and its partners is bistatic, sending a continuous signal from one station and receiving the return signal at another.

The ESA plans to evaluate the data from both radar systems.

Scientists estimate that about 700,000 small pieces of space debris are orbiting the Earth, threatening maritime navigation, communications, television and weather satellites. EFE