It sounds like a joke -- a U.S. intelligence agency relying on software that can be downloaded for free on the internet to turn complicated data from spy satellites into detailed maps.

But a remarkable collaboration between the government, private industry and academia may lead to just that: downloadable satellite-image processing software called OSSIM, or Open Source Software Image Map.

The National Imagery and Mapping Agency (NIMA), which provides maps to defense and intelligence agencies, has sponsored the project to see if a programming method called Open Source can benefit the world of spying.

Proprietary software like Microsoft Word is distributed in a form that is unintelligible to programmers, unlike Open Source programs, and thus impossible to modify.

Once just a part of hacker culture, Open Source software has become big business, with companies like Red Hat selling support and service on its version of the Linux operating system. And much of the behind-the-scenes software that runs the internet has been developed through Open Source.

Traditionally, when the government wants software, it goes through a lengthy period of goal setting, bidding, and contracting. With Open Source, the government loses some control, but programmers are free to begin developing immediately.

And that has been the case with OSSIM. In two months, the programmers have created a limited working prototype that can interpret satellite data and create visual maps.

OSSIM can be downloaded and modified by anyone, though the primary contributors are Imagelinks, a remote-sensing company, and the Florida Institute of Technology. A consultant from Canada is contributing as well, without pay.

Mark Lucas, the chief technology officer of Imagelinks, said Open Source software can evolve faster than closed software. "We all think that Open Source software development is a paradigm shift in the way software is going to be developed," Lucas said. "Over time, if there's an Open Source solution, it will eventually become equivalent and then beat out any proprietary solution."

The OSSIM project will be analyzed in October to assess the software's abilities and to see whether the Open Source process is working. Meanwhile, Chung Hye Read, a physical scientist at NIMA who is involved in the project, said she is "very impressed" with OSSIM to this point. "We want to use all the commercial expertise and knowledge, rather than just one organization," she said. "Open source will give us a lot more flexibility."