* Astronomy

  New space radars to track small but deadly space junk

Independent tests undertaken in late February by two US aerospace firms - Lockheed Martin and Raytheon - showed that a new ground-based radar technology can detect  small bits of orbital debris.
Both Lockheed and Raytheon are competing to win a US air force contract to build what's called the Space Fence, which will detect, track and identify debris. The Space Fence is designed to overcome a fundamental limit in the Air Force Space Surveillance System, which was built in 1961 to spot Russian Sputniks during the cold war. Its three very high-frequency band radar sites in Texas, Arizona and Alabama ping the heavens with radio waves at wavelengths between 1 and 10 metres and their reflections enable us to detect objects down to the size of a basketball.
To detect smaller objects, radar scanners must operate at wavelengths between 1 and 10 centimetres, in the so called S-band of the electromagnetic spectrum.
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