There was a time when the Department of Homeland Security wasn't enthusiastic about its drone fleet. Unmanned flying surveillance 'bots had the potential to freak out the public, top DHS science and technology officials worried. That time has evidently passed – particularly for smaller flying spies.

In the coming months, Fort Sill, Oklahoma will become a proving ground to learn what small surveillance drones can add to "first responder, law enforcement and border security scenarios," according to a recent solicitation to the country's various drone manufacturers. Each selected drone wil undergo five days' worth of tests as part of a new program from DHS' Science and Technology directorate, called Robotic Aircraft for Public Safety or, gloriously, RAPS.

Like many in the military experimenting with drone miniaturization, DHS is thinking small. The drones it wants to bring to Fort Sill will ideally be launched by hand, like the Army and Marines' Raven. They should weigh under 25 pounds. Assembly should take a matter of minutes, and training for their remote pilots and technician a matter of days. DHS isn't looking for drones that can loiter over an area for a long time: just 30 minutes to two hours, a hint that the department doesn't foresee drones becoming a primary surveillance tool. "Law enforcement operations, search and rescue, and fire and hazardous material spill response" are some of the potential drone missions the RAPS program envisions.

Still, it's something of a turnaround for DHS. Back in January 2011, Ruth Doherty, a DHS science & tech official, expressed skepticism about using drones to patrol for signs of terrorism or to protect big public events like the Super Bowl. "A case has to be made that they're economically feasible, not intrusive and acceptable to the public," Doherty told Danger Room at a D.C. conference. In addition to the potential public outcry, drones have been a headache for DHS at times. A DHS ground station in 2010 lost communications with one of the first Predators it used to surveil the southern U.S. border, and the department has had trouble finding enough pilots and technicians to operate its initial drone fleet.

Police shops around the country have only recently begun flying surveillance drones, owing in part to cumbersome Federal Aviation Administration restrictions designed to prevent the robots from slamming into commercial passenger aircraft. That could be an issue for DHS as well. The RAPS drones need a threshold altitude of 1000 feet, well into helicopter territory – above the tops of most skyscrapers – and comparable to the heights reached by "Flying Beer Keg" flown by the Miami-Dade police department.

DHS' second thoughts on drones may not be so surprising. In recent years, DHS has gotten interested in vastly expanding its surveillance capabilities, exploring cameras reminiscent of military ones that can spy on four square miles at once. And since it's generally cheaper to fly a small drone over a burning building, nuclear power plant or hostage situation than it is to hire and clear a manned plane or helicopter, it may only have been a matter of time before homeland security opened up to the domestic-drone boom.