Space Base Solar

The thing most surprising about space is the scale.  Everything is unbelievably vast, massive, and powerful.  It is as close to unlimited as there is.

Earth on the other hand is quickly running out of it’s limited resources, and everything is we do is confined within limits of a minuscule skin of air.  One of the things that stand out for astronauts in their perspective from orbit is just how tenuous things really are.

Almost everything on the Earth is powered by the sun.  Sunlight powers the growth of plants, which generates oxygen, evaporates oceans to create the clouds and winds.  We receive roughly  .0000002 % of the suns solar energy to drive everything on the planet.

That leaves a shocking amount of energy lost to the vastness of space.

Time to do some rough math…

It’s estimated that by 2030 it will take roughly 500,000 square KM of solar panels to meet the electrical needs of the world. Half of that would be in darkness at any one time so we need 250,000 sq. km. in the sun at any one time.

The Earth is 149,669,180 km from the sun.  the surface area of a sphere is given by A = 4*pi r^2 which gives 2.8149755e+17 sq. km.  So at our current distance from the sun we need just 8.8810719e-13 of the sun’s energy (250,000/2.8e17).

Space based solar collection doesn’t have to tend with clouds and losses due to the atmosphere reflecting.  It’s estimated to be about 50% more efficient than land based solar.  So about 167,000 sq km. (5.96e-13 of the sun)

How much space would it take if we put the solar panels just inside the orbit of Mercury, at the closest we’ve been to the sun (on the Helios missions 43 million km) so that it could power the world?  5.96e-13  = x/(4*pi*43000000^2) solve for x gives:  13,850 sq. km or roughly the size of Bahamas.

Canada uses just a bit less than 3% of the global electricity production.  So to power every house, factory, streetlight and business in Canada would be about 400 sq km or half the size of the city of Calgary.

Sadly, with our current technology building something like this is out of reach.