Power
for Hubble omes from the electrical power system.
The major components are two solar array wings,
six nickel-hydrogen batteries, six charge-current
controllers, one power control unit, and four
power distribution units. The solar arrays are
the primary source of electrical power. The arrays
are nearly eight feet by forty feet. Each array
has a solar cell blanket that converts sunlight
into electrical energy. Electricity produced by
the solar arrays charges Hubbles' batteries. The
solar arrays supply power to the spacecraft and
charge the batteries while in the sunlit part
of the orbit. The batteries take over supplying
power during the night portion of the orbit (when
Hubble is in the Earth's shadow).
This photo shows astronaut Kathy Thornton jettisoning
the damaged solar panel into space. During the
First Servicing Mission, when the solar panels
were changed out, astronauts detected a bend in
the panel casing. The panel couldn't safely be
returned to Earth and was jettisoned into space.
According to NORAD, the Hubble solar array reentered
Earth's atmosphere on October 28, 1998 at 12:08
a.m. EST.
