Solar Panels used on Spacecraft (Space Based Solar Power)

Introduction to Space Based Solar Power (SBSP)

Space-based solar power (SBSP), originally called space solar power (SSP) in 1968, is a system for capturing power from the sun in space and transferring it back to the earth. The concept of using solar power in space is by no means new, as solar hardware has always been used on space shuttles and other related equipment such as rovers.

In outer space, sunlight is completely unfiltered in contrast to sunlight available on the earth, which is blocked by the day night cycle, weather, and by the ozone and atmosphere. The raw power of sunlight in outer space available for a satellite, space station, rovers and shuttles is ten times that available on earth, which is why they are all usually covered with solar cells, to one extent or another.
Solar Panels in Out Space
Photovoltaic cells are modules designed to capture radiant energy from the sun and convert it to electrical energy. The earliest PV cells operated with an efficiency of only 1%, while present technology allows up to 40.8% efficiency or more. Space Based Solar Power SBSP is usually designed so that the solar panels can continually keep the PV array facing the sun based on a tracking mechanism.

Image: An artist's conception of space based solar power (image from Nasa). Sunlight energy in space, above the Earth's atmosphere is exponentially more powerful than light that can be received on the planet surface. Science fiction authors, such as Isaac Asimov envisioned use of this type of energy many years ago. Present technology has not allowed us to tap this energy source but hopes remain high this will change in the near future.


The panels are not always faced directly to the sun because often the electricity required is less than the amount made. Extra power is allowed to escape through a shunt into space. Although there is no weathering in space, one must consider micrometeoroids or cumulative damage caused by constant high levels of radiation. This is why low orbit satellites lose about 1-2% power production per year and mid to high orbit satellites lose as much as 50% of their power generating capacity in just one year.

Fresnal lenses, invented by Augustin Jen Fresnel in 1822, focus the sunlight onto specific areas where solar power is collected. These lenses operate in a manner similar to a magnifying glass, bending and focusing the light onto the solar cells, which are built to absorb sunlight energy. Fresnal lenses are also used by theaters and lighthouses, allowing the focused light to extend further than otherwise.

SBSP: Still Fiction, but With Great Potential

Although not fully realized, or implemented yet, the massive potential of space based solar power has been recognized by many. For example, way back in 1941, Isaac Asimov wrote 'reason' a book about solar power troubles caused by robots in a space station. The huge amount of raw sunlight based power available in space keeps government, scientists and businesses searching for a way to make SBSP a reality.