all right welcome aboard the
International Space Station
I'm astronaut Ricki Arnold and I'm
currently at one of our human research
facilities on ISS where you can see
centrifuges laptops and other scientific
equipment across from me is another one
ease experiment racks where you can see
ultrasound imaging more laptops cameras
other equipment all stuff that requires
electrical power in fact we have so much
equipment for science and life support
that our electrical system has about
eight miles or 13 kilometers of wiring
to make it all work so where does this
energy come from let's have a look from
here in the cupola and through other
windows you can easily see the solar
rays soaking in the sunlight they are
massive these four solar arrays are made
of solar cell which are purified chunks
of the element silicon together the
solar arrays contain a total of 260
2,400 solar cells and cover an area of
about 27,000 square feet more than half
the area of a football field that's huge
when the station is in sunlight the
solar arrays produce about 60 percent
more power than we actually need during
the daytime that extra power goes
directly to charging our lithium-ion
batteries now those batteries are
essential because they provide the power
we need during the 16 night times we
have per day here on the space station
the energy our solar arrays can produce
is enough to power 40 homes and we can
maximize the power we generate by
rotating their arrays and two axes one
like a windmill to track the Sun through
the course of the day the other the
track the sun's inclination or its angle
in the sky
the space stations electrical power
system uses direct current to provide
energy for our laptops lights water
recovery system and science experiments
thanks for coming aboard today now back
to earth