Energy and the International Space Station

Last week the International Space Station unfurled the last of its 8 paired solar panel arrays (each array is composed to two long panels, 5m by 34m long). The photo above, taken last week by the departing space shuttle, Discovery, shows all of the panels now in place.

How much energy does it take to run the space station?  Well, basic life support and essential operations on the station requires about 20 kilowatts (kW).  A single array generates around 15kW but they are exposed to sunlight only half the time.  Thus, approximately three of the 8 arrays are necessary for life support.

A typical home in Canada uses a bit more than 1kW on average (about 11,000 kWhr/yr).  This means that the 5 arrays not required for life support would provide enough energy for approximately 35 homes. 

How much did those arrays cost?  Each of the eight run about $300 million.  The station shown above is now estimated to be worth $100 billion.

Worth it?  I don't think so.  For that cost we could be seriously exploring the solar system using robots.  Is there life under the ice of Europa (one of Jupiter's moons) or on Titan (a moon of Saturn)?  These are questions 100 billion could have answered.

Photo credit: NASA, Discovery (STS-119, Shuttle Crew, March 25, 2009)