But in the last few years, the EPA's Aero Commander 680 has been pressed into duty for national security. The Commander carries high-tech sensors known as Aspect, for Airborne Spectral Photometric Environmental Collection Technology.

Aspect uses two sensors. An infrared spectrometer detects and locates chemical vapors. It can peer through smoke and dust to locate the vapor flume and record its density. A high-resolution infrared scanner records an image of the ground and the plume. Information from both sensors is combined with high-resolution digital imagery and GPS data to create a detailed map. It takes only minutes to produce an image. The map can then go to emergency response commanders on the ground by fax or computer. If necessary, Aspect can drop a computer via parachute to emergency responders.

The Aspect Commander monitored events such as the 2002 Olympic games, the crash of the space shuttle Columbia (with its release of toxic fuel), and this year's presidential inauguration.