Washington, DC (WIBX) - The National Nuclear Security Administration (NNSA) is testing naturally occurring radiation in the skies above Washington, D.C.

The NNSA is letting the public know that it should not be alarmed by seeing a   helicopter flying 150 feet or so above the ground at a speed of about eighty miles an hour.

The chopper has remote gamma radiation sensing technology on board and will be measuring radiation in an effort to establish baseline levels of radiation so that subsequent levels can be adequately monitored.

The tests are expected to be completed by January 11, 2013.

The NNSA is a subsidiary of the United States Department of Energy and is charged with preparing for, and responding to, nuclear and radiological events.

In a release published on the agency's website the tests are "a normal part of security and emergency preparedness."