pole on August 4, 1969, it sent back pictures of ice-filled craters and outlines of the south polar cap. Despite the communication defect suffered by Mariner 7 earlier, these pictures were of better quality than what had been sent by its twin, Mariner 6, a few days earlier when it flew past the martian equator. In total, 201 photos were taken and transmitted back to Earth, adding more detail than the earlier mission, Mariner 4. Both crafts also studied the atmosphere of Mars. Coming a week after Apollo 11, Mariner 6 and 7's flyby of Mars received less than the normal amount of media coverage for a mission of this significance. The ultraviolet spectrometer onboard Mariners 6 and 7 was constructed by University of Colorado's Laboratory for Atmospheric and Space Physics (LASP). The engineering model of Mariners 6 and 7 still exists, and is owned by the Jet Propulsion Laboratory (JPL). It is on loan to LASP, and is on display in the lab's lobby. Mariner 6 and 7 infrared radiometer observations helped to trigger a scientific revolution in Mars knowledge. The Mariner 6 and 7 infrared radiometer results showed that the atmosphere of Mars is composed mostly of carbon dioxide (CO2), and they were also able to detect trace amounts of water on the surface of Mars. Spacecraft and subsystems The Mariner 6 and 7 spacecraft were identical, consisting of an octagonal magnesium frame base, diagonally and deep. A conical superstructure mounted on top of the frame held the high-gain diameter parabolic antenna and four solar panels, each measuring x , were affixed to the top corners of the frame. The tip-to-tip span of the deployed solar panels was . A low-gain omnidirectional antenna was mounted on a high mast next to the high-gain antenna. Underneath the octagonal frame was a two-axis scan platform which held scientific instruments. Overall science instrument mass was . The total height of the spacecraft was . The spacecraft was attitude stabilized in three axes, referenced to the sun and the star Canopus. It utilized 3 gyros, 2 sets of 6 nitrogen jets, which were mounted on the ends of the solar panels, a Canopus tracker, and two primary and four secondary sun sensors. Propulsion was provided by a 223-newton rocket motor, mounted within the frame, which used the mono-propellant hydrazine. The nozzle, with 4-jet vane vector control, protruded from one wall of the