was approximately $554 million. Spacecraft and subsystems The Mariner 8 spacecraft was built on an octagonal magnesium frame, deep and across a diagonal. Four solar panels, each , extended out from the top of the frame. Each set of two solar panels spanned from tip to tip. Also mounted on the top of the frame were two propulsion tanks, the maneuver engine, a long low gain antenna mast and a parabolic high gain antenna. A scan platform was mounted on the bottom of the frame, on which were attached the mutually bore-sighted science instruments (wide- and narrow-angle TV cameras, infrared radiometer, ultraviolet spectrometer, and infrared interferometer spectrometer). The overall height of the spacecraft was . The launch mass was , of which were expendables. The science instrumentation had a total mass of . The electronics for communications and command and control were housed within the frame. Spacecraft power was provided by a total of 14,742 solar cells which made up the 4 solar panels with a total area of area. The solar panels could produce 800 W at Earth and 500 W at Mars. Power was stored in a 20 ampere hour nickel-cadmium battery. Propulsion was provided by a gimbaled engine capable of 1340 N thrust and up to 5 restarts. The propellant was monomethyl hydrazine and nitrogen tetroxide. Two sets of 6 attitude control nitrogen jets were mounted on the ends of the solar panels. Attitude knowledge was provided by a Sun sensor, a Canopus star tracker, gyroscopes, an inertial reference unit, and an accelerometer. Passive thermal control was achieved through the use of louvres on the eight sides of the frame and thermal blankets. Spacecraft control was through the central computer and sequencer which had an onboard memory of 512 words. The command system was programmed with 86 direct commands, 4 quantitative commands, and 5 control commands. Data was stored on a digital reel-to-reel tape recorder. The 8-track tape could store 180 million bits recorded at 132 kbit/s. Playback could be done at 16, 8, 4, 2, and 1 kbit/s using two tracks at a time. Telecommunications were via dual S-band 10 W/20 W transmitters and a single receiver through the high gain parabolic antenna, the medium gain horn antenna, or the low gain omnidirectional antenna. See also Exploration of Mars List of missions to Mars Space exploration Timeline of artificial satellites and space probes Unmanned space missions