Google's secretive department of moonshots, Project X, has filed documents with the FCC that could suggest it plans to begin testing Project Loon internet balloons in the US.
Google is seeking an experimental radio license from the Federal Communications Commission that would allow it to test wireless technologies across all 50 states in the US, as well as Puerto Rico, for two years beginning on January 1, 2016.
Much of the application has been redacted under Google's request for confidentiality but there are a few signs that point to Project Loon. For example, the technical lead for the application is a member of Project X, the group behind Project Loon as well as Google's autonomous vehicle and drone projects.
So far, Google's main drive for Project Loon has been to bring the internet to parts of the world with poor broadband infrastructure by using a patchwork of networked balloons floating at 20km (60,000 feet) to beam 4G LTE signals back down to earth.
The company has been working on methods for scaling up production and testing its balloon technology, earlier this week revealing a facility that essentially brings the stratosphere down to earth.
Its new sub-zero facility at McKinley Climatic Lab allows it to test whole balloons at -40 to -60 degrees centigrade (-40F to -76F).
Normally, Loon testing has involved assessing balloons after a flight where they endure temperatures of down to -60 degrees centigrade (-76F), or alternatively taking a patch of the material and subjecting it to similar conditions.
Last month the company also announced its intention to bring Project Loon to Indonesia in what could be the largest deployment to date, with plans to deliver LTE connections to more than 100 million people across 17,000 islands. As with earlier trials, it's partnering with local mobile operators to deliver connections.
Business Insider, which first reported the application, noted that Google seeks to build on earlier tests conducted in Winnemucca, Nevada, whose local council in 2014 had granted permission for the search giant to use its airport industrial park as a "temporary balloon launching facility".
Additionally, and somewhat mysteriously, Google has applied to use frequencies in the 71GHz to 76GHz and the 81GHz to 86GHz ranges.
Those are extremely high-frequency ranges often linked with so-called millimetre wave technology that some network equipment vendors are exploring for 5G.
Google in 2014 sought to use these bands under an FCC application signed by the head of its Google Access division, driving speculation it was exploring its use for Google Fiber.