QUESTION:
Will the spacecraft use solar panels to provide power to the instruments on Cassini?

ANSWER from FAQ on June 11, 1999:
No. Cassini will use Radioisotope Thermoelectric Generators or RTGs. To
identify the most appropriate power source for the Cassini mission,
NASA's Jet Propulsion Laboratory conducted an in-depth analysis of the
available electrical power systems, including ones that use solar
energy. The power demand is between 600-700 watts produced reliably for
many years at a distance that is 9.55 times farther from the Sun than
Earth. This demand must be met while keeping the spacecraft small enough
and light enough to be launched from Earth. For comparison, the power
demand for an average residential home in America is about 1400 watts. A
Cassini spacecraft equipped with the highest efficiency solar cells
available (including the new high-efficiency cells under development by
the European Space Agency) would make the spacecraft too heavy for
launching to Saturn. The resulting solar arrays would cover an area
larger than two tennis courts. RTGs are the only feasible power system
for the Cassini mission. Cassini will have three RTGs. The RTGs will
start the mission providing 820 watts of power, and end the mission
providing 650 watts. The power output declines because RTGs generate
energy from a radioactive substance called plutonium which decays with
time.