That's a rad copter overhead

The National Nuclear Security Administration reminds us today that it has a helicopter flitting above us doing its annual background radiation checks in preparation for the Marathon.

A twin-engine Bell 412 helicopter, operated by the Remote Sensing Laboratory Aerial Measuring System from Joint Base Andrews, will be equipped with radiation sensing technology. The helicopter will fly in a grid pattern over the area at 150 feet (or higher) above the ground surface, at a speed of approximately 80 miles per hour. Flyovers will occur only during daylight hours and are estimated to take about two days to complete.

The measurement of naturally occurring radiation to establish baseline levels is a normal part of security and emergency preparedness. NNSA is making the public aware of the upcoming flights so that citizens who see the low-flying aircraft are not alarmed.