Powering the International Space Station

How will the International Space Station (ISS) be powered up? It will run with the Sun! Yep, solar power will be used to generate electricity for life support systems, daily operations and scientific equipment.

Start Me Up!

The Sun is the only available source of energy that can power up the Space Station. So four pairs of solar panels will be secured to the ISS to gather its rays.

They’ll be set up beyond the Station’s main body so they look like the wings of a bird in flight. They measure 70 metres (m) by 10 (m) from tip to tip. They’ll generate enough energy to power 55 houses! Approximately 40% of that energy will be used for research experiments within the ISS.

To generate this amount of power, the panels convert sunlight into energy via an enourmous number of photovoltaic cells within each individual solar panels. Energy is then stored in rechargeable nickel hydrogen batteries. This guarantees that the Station gets continuous power, even when it is in the shadow of the Earth.

Energy storage in these replaceable batteries is important because the Station spends a lot of time in darkness. Why? The Station circles the Earth at a speed of almost 30 000 kilometre (km) per hour, which means it sees 16 sunrises and sunsets within a day! The Earth blocks the rays of the Sun to the Space Station so that the Station is in darkness for 36 minutes (min) of each 90 min orbit.

Feel the Heat

This constant change from light to dark also presents another challenge: extreme temperature changes from -149°C to 126°C. Yikes! Heat doesn’t circulate in space the same way it does on Earth. What’s the solution?

Remember, the solar panels gather a lot of light from the Sun and convert it into energy. The energy powers the Space Station’s equipment. The equipment in turn creates a lot of heat. This heat is then collected by another set of panels which sends the heat out into space. These panels form a radiator system that contains ammonia—an excellent substance for transporting heat and resisting those crazy temperature changes!


Even in outer space, the Space Station can experience a power surge! To protect the Station, the scientists have designed a Plasma Contractor Unit. Ooh! Ah! Sounds like a space toy to play with, but it’s pretty serious stuff!

Space plasma floats around. These floating bits carry their own electrical charge. If they make contact with the Space Station, they can produce a power surge which could hurt not only the Station, but also the crew and equipment on board!

The job of the Plasma Contractor Unit is to take away the electric charge carried by the space plasma. The unit converts the possibly harmful gas (space plasma) into ions and electrons which are then released harmlessly into space – problem over!