By Alwyn Scott

NEW YORK (Reuters) - The U.S. government took a step on Monday toward opening the skies to aerial drones, authorizing six sites where unmanned aircraft can be tested for a variety of uses.

The Federal Aviation Administration already had approved limited use of drones in the United States for law enforcement, surveillance, atmospheric research and other applications.

Monday's decision will give companies, universities and others place to test much broader uses, such as crop spraying, catching exotic-animal poachers or delivering packages, as Amazon.com Inc recently suggested.

"It provides the platform for this research to be carried out on a very large scale across the country," FAA Administrator Michael Huerta told reporters.

While the test sites were hailed by governments and industry as a major milestone that would bring broad economic benefits to the winning regions, they also renewed privacy and safety concerns about the aircraft, which can hover over cities and record people's movements with sophisticated video cameras.

Drones are popular with law enforcement in part because they are smaller and less costly alternatives to manned aircraft. They also are a growing business for companies such as Boeing Co, Northrop Grumman Corp, Lockheed Martin Corp and AeroVironment Inc.

Global spending on unmanned aircraft is expected to nearly double to $11.6 billion a year by 2023, according to aviation and aerospace industry research firm Teal Group.

The Association for Unmanned Vehicle Systems International (AUVSI), estimates the industry could contribute more than $80 billion to the U.S. economy over a decade and create more than 100,000 jobs.

PRIVACY CONCERNS

But since 2012, when congress required the FAA to establish a roadmap for the broader use of drones, 42 states have considered restrictions based on privacy or safety concerns, according to the American Civil Liberties Union. Eight states have passed such laws, and most require probable cause warrants before the surveillance can be used in criminal cases.

Story continues

The FAA already has approved more than 300 requests for unmanned aircraft use, and many have raised safety issues more than privacy. But as technology improves in the absence of a privacy policy, fears of "Big Brother" in the sky have grown.

"You can imagine a world in which it is impossible to walk out of your house without being subjected to persistent monitoring and recording by drones," said Catherine Crump, a staff attorney with the American Civil Liberties Union in New York. "Things that might have seemed like science fiction will be here before we know it."

Operators of the new FAA test sites are required to develop a written privacy policy, and to address safety concerns, but it is not clear whether the policies will protect privacy.

"Online privacy policies don't require that websites protect privacy," said Jennifer Lynch, a senior staff attorney at the Electronic Frontier Foundation, a digital rights organization. "We still don't know what data the drones are going to be gathering at the test sites."

The FAA chose the six sites, in Alaska, New York, North Dakota, Texas, North Carolina and Virginia, from the 25 applications it received from 24 states. The agency is required to write initial rules governing the commercial operation of drones by 2015.

Huerta said the FAA would first address the use of drones in small civil applications and expected to propose a rule in early 2014.

ALREADY TESTING

Two of the states that passed drone laws, Texas and Virginia, were among those awarded test sites on Monday, but both had exemptions for research-related drone use.

The Texas law, for example, excludes flights or testing at sites approved by the FAA, said Gloria Gallardo, director of media relations at Texas A&M Corpus Christi, which was among the six sites selected.

Texas landowners must approve any test flights over their property, but since much of the 6,000 square miles in the Texas test area is state-owned, the owner is "almost certain to grant permission," she said.

The other five sites will be developed by the University of Alaska, the state of Nevada, Griffiss International Airport in New York state, the North Dakota Department of Commerce, and Virginia Polytechnic Institute and State University, which includes locations in New Jersey.

The first test site is expected to be open in six months and the sites will operate at least until February 2017.

But some locations already have other tests going on, and research money available.

One of several tests in North Dakota, for example, looks at how to train pilots to fly unmanned vehicles for the U.S. Air Force, said Al Palmer, director of the Center for Unmanned Aircraft Systems Research at the University of North Dakota.

"We're flying unmanned vehicles right now," he said.

North Dakota's FAA test site will study, among other things,

human factors that can affect pilots, from the design and layout of the remote controls to dealing with long flights that can last 36 hours, he said.

The state also has created a 19-member committee to review all tests, much like an ethics review board for human drug trials, said Bob Becklund, director of the Northern Plains Unmanned Aircraft Systems Authority, an organization set up by the state to guide its drone programs.

And the state has set aside taxpayer money, even for private companies, and will match their investment dollar for dollar. The state contacted Amazon this month after the company unveiled plans for drone-delivered packages.

"We said: 'We'd love to help you bring your vision to fruition,'" Becklund said. They said: "We'll keep your number on file."

(Reporting by Alwyn Scott; additional reporting by Jim Forsyth in San Antonio, Texas; Editing by John Wallace, Diane Craft and Andre Grenon)