Two solar arrays, each 3.53 meters (11.6 feet) long by 1.85 meters (6.1 feet) wide will gather power from the Sun to generate electricity. Each array mounts to the main body of the spacecraft close to the attachment point between the equipment and propulsion modules. Rectangular-shaped, metal flaps attached at the ends of both arrays add another 81.3 centimeters (32 inches) to the overall structure. These "drag flaps" serve no purpose other than to increase the spacecraft's susceptibility to air resistance when it flies through the Martian atmosphere to lower its orbit.
Each array consists of two panels, an inner and outer panel comprised of gallium arsenide and silicon solar cells, respectively. During mapping operations at Mars, the amount of power produced by the arrays will vary from a high of 980 Watts when Mars is closest to the Sun, to a low of about 660 Watts when Mars is farthest from the Sun. In order to understand the difficulty of designing and operating an interplanetary spacecraft, consider the fact that 980 Watts is less power than that used by an ordinary hair dryer.
While in orbit around Mars, the solar arrays will provide power as Surveyor flies over the day side of the planet. When the spacecraft passes over the night side, energy will flow from two nickel-hydrogen (NiH2) batteries to compensate for the temporary loss of power from the solar arrays. These two batteries can provide power for over an hour before requiring a recharge from the solar arrays.