By Brandon Bailey San Jose Mercury News

If you were Google Inc., what would you do with a 350,000-square-foot hangar built to house helium airships for the U.S. Navy?

How about using its cavernous interior for building and testing new robots, planetary rovers and other space or aviation technology?

A NASA spokeswoman confirmed last week that those plans are part of the proposal submitted by a subsidiary of the giant Internet company, along with restoring the outside of the structure known as Hangar One at Moffett Federal Airfield in California.

Based on that proposal, U.S. officials said they will negotiate a long-term lease with Google for a significant portion of the former naval base, including three hangars, two runways and some adjacent land and buildings.

While the company is best known for its Internet search engine, software and other online services, Google's founders and several top executives also have a well-documented interest in robots, high-altitude balloons, aviation and space exploration.

In recent months, Google has confirmed buying eight small robotics companies for a mysterious new division headed by its former Android software chief, Andy Rubin. Google co-founders Larry Page and Sergey Brin already own a fleet of jets now parked at Moffett Field. And Page, the company's CEO, has reportedly invested in a separate company that hopes to mine asteroids for precious metals.

While a Google spokeswoman didn't respond to requests for more details about the company's plans, it's clear the massive Hangar One would provide plenty of room for tinkering.

The Depression-era structure is 200 feet tall and covers 8 acres. All told, the proposed lease would provide more than 1 million square feet of space in Hangar One and its two neighbors, known as Two and Three.

Officials at NASA and the U.S. General Services Administration, which helps administer federal property, said only that the proposal from Google subsidiary Planetary Ventures described using all three historic hangars for "research, testing, assembly and development" of new technology related to space, aviation and "rover/robotics."

The proposal also calls for building a new 90,000-square-foot structure on the property that Planetary Ventures would make available "at no cost" for a "public benefit educational/museum/incubator," GSA spokeswoman Jackeline Stewart said.

Since it was decommissioned in 1994, the sprawling, 2,000-acre Moffett property has been home to a mix of private tenants and government agencies, including NASA's Ames Research Center and a wing of the California Air National Guard. NASA currently occupies about 500 acres, but the government has negotiated long-term leases for other portions.