The final image taken before impact has a resolution of 0.5 meters. Transmission of 4,308 photographs of excellent quality occurred over the final 17 minutes of flight. The first image was taken at 13:08:45 UT at an altitude of 2110 km. The F-channel began its one minute warm up 18 minutes before impact. The only anomaly during flight was a brief loss of two-way lock on the spacecraft by the DSIF tracking station at Cape Kennedy following launch. The next day, 29 July, the planned mid-course maneuver was initiated at 10:27 UT, involving a short rocket burn. After separation from the Agena, the solar panels were deployed, attitude control activated, and spacecraft transmissions switched from the omniantenna to the high-gain antenna. Half an hour after launch the second burn of the Agena engine injected the spacecraft into a lunar intercept trajectory. The Atlas 250D and Agena B 6009 boosters performed nominally at launch inserting the Agena and Ranger into a 192 km altitude Earth parking orbit. Sufficient video bandwidth was provided to allow for rapid framing sequences of both narrow- and wide-angle television pictures. The telecommunications equipment converted the composite video signal from the camera transmitters into an RF signal for subsequent transmission through the spacecraft high-gain antenna. Transmitters aboard the spacecraft included a 60 W TV channel F at 959.52 MHz, a 60 W TV channel P at 960.05 MHz, and a 3 W transponder channel 8 at 960.58 MHz. Two 1000 Watt-hr AgZnO batteries stored power for spacecraft operations.Ĭommunications were through the quasiomnidirectional low-gain antenna and the parabolic high-gain antenna. Two 1200 Watt-hr AgZnO batteries rated at 26.5 V with a capacity for 9 hours of operation provided power to each of the separate communication/TV camera chains. Power was supplied by 9792 Si solar cells contained in the two solar panels, giving a total array area of 2.3 square meters and producing 200 W. Orientation and attitude control about 3 axes was enabled by 12 nitrogen gas jets coupled to a system of 3 gyros, 4 primary Sun sensors, 2 secondary Sun sensors, and an Earth sensor. Propulsion for the mid-course trajectory correction was provided by a 224-N thrust monopropellant hydrazine engine with 4 jet-vane vector control. The overall height of the spacecraft was 3.6 m. A cylindrical quasiomnidirectional antenna was seated on top of the conical tower. Two solar panel wings, each 73.9 cm wide by 153.7 cm long, extended from opposite edges of the base with a full span of 4.6 m, and a pointable high gain dish antenna was hinge mounted at one of the corners of the base away from the solar panels. The spacecraft consisted of a hexagonal aluminum frame base 1.5 m across on which was mounted the propulsion and power units, topped by a truncated conical tower which held the TV cameras. Rangers 6, 7, 8, and 9 were the so-called Block 3 versions of the Ranger spacecraft. No other experiments were carried on the spacecraft. The cameras were arranged in two separate chains, or channels, each self-contained with separate power supplies, timers, and transmitters so as to afford the greatest reliability and probability of obtaining high-quality video pictures. The spacecraft carried six television vidicon cameras, 2 full-scan cameras (channel F, one wide-angle, one narrow-angle) and 4 partial scan cameras (channel P, two wide-angle, two narrow-angle) to accomplish these objectives. Ranger 7 was designed to achieve a lunar impact trajectory and to transmit high-resolution photographs of the lunar surface during the final minutes of flight up to impact.
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