Scientists at the US Naval Research Laboratory (NRL) are working on a project to capture solar power in space and send it down to Earth.

Paul Jaffe, a spacecraft engineer at NRL, has built two different prototypes of space solar modules. In the “sandwich” design, one side receives solar energy with a photovoltaic panel; electronics in the middle convert that direct current to a radiofrequency; and the other side has an antenna to beam power away, according to NRL.

The second module design, now in the patent process, opens up the “sandwich” to look more like a zig-zag. This allows heat to radiate more efficiently, so the module can receive greater concentrations of sunlight without overheating.

To test the technology, NRL built a vacuum chamber just big enough for one module. In it, Jaffe can expose the module to the simulated extreme cold of space and concentrated solar intensities, mimicked by turning on two powerful xenon lamps in the same spectrum as the sun.

The research would have to overcome some obstacles to become a reality. The first is scale: The International Space Station stretches a little longer than an American football field; the space solar array would be about nine times larger. Also, there is the problem of funding. The project cuts across many different federal agencies. The work to date has been funded from NRL’s base research budget.