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Originally a public domain film, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).
https://en.wikipedia.org/wiki/Atlas_LV-3B
Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/
The Atlas LV-3B, Atlas D Mercury Launch Vehicle or Mercury-Atlas Launch Vehicle, was a human-rated expendable launch system used as part of the United States Project Mercury to send astronauts into low Earth orbit. Manufactured by American aircraft manufacturing company Convair, it was derived from the SM-65D Atlas missile, and was a member of the Atlas family of rockets.
The Atlas D missile was the natural choice for Project Mercury since it was the only launch vehicle in the US arsenal that could put the spacecraft into orbit and also had many flights from which to gather data. But its reliability was far from perfect, and Atlas launches ending in explosions were an all-too common sight at Cape Canaveral. The Atlas had also been originally designed as a weapon system, thus its design and reliability did not need to necessarily be 100% perfect. As such, significant steps had to be taken to human-rate the missile and make it safe and reliable unless NASA wished to spend several years developing a dedicated launch vehicle for crewed programs or else wait for the next-generation Titan II ICBM to become operational. Atlas' stage-and-a-half configuration was seen as preferable to the two stage Titan in that all engines were ignited at liftoff, making it easier to test for hardware problems during pre-launch checks.
Shortly after being chosen for the program in early 1959, the Mercury astronauts were taken to watch the second D-series Atlas test, which exploded a minute into launch. This was the fifth straight complete or partial Atlas failure and the booster was at this point nowhere near reliable enough to carry a nuclear warhead or an uncrewed satellite, let alone a human passenger. Plans to human-rate Atlas were effectively still on the drawing board and Convair estimated that 75% reliability would be achieved by early 1961 and 85% reliability by the end of the year. Despite the Atlas' developmental problems, NASA had the benefit of conducting Project Mercury simultaneously with the Atlas R&D program which gave plenty of test flights to draw data from as well as test modified equipment for Mercury...
Aside from the modifications described below, Convair set aside a separate assembly line dedicated to Mercury-Atlas vehicles which was staffed by personnel who received special orientation and training on the importance of the crewed space program and the need for as high a degree of top-quality workmanship as possible... components and subsystems with excessive operating hours, out-of-specification performance, and questionable inspection records would be rejected. All components approved for the Mercury program were earmarked and stored separately from hardware intended for other Atlas programs and special handling procedures were done to protect them from damage. The factory inspection of Mercury vehicles was performed by Convair personnel specially chosen for their experience, familiarity with the Atlas hardware, and who had demonstrated a favorable disposition and work ethic...
Systems modified
Abort sensor
Central to these efforts was the development of the Abort Sensing and Implementation System (ASIS), which would detect malfunctions in the Atlas's various components and trigger a launch abort if necessary...
Rate gyros
The rate gyro package was placed much closer to the forward section of the LOX tank due to the Mercury/LES combination being considerably longer than a warhead and thus producing different aerodynamic characteristics (the standard Atlas D gyro package was still retained on the vehicle for the use of the ASIS). Mercury-Atlas 5 also added a new reliability feature—motion sensors to ensure proper operation of the gyroscopes prior to launch...
Range safety
The range safety system was also modified for the Mercury program. There would be a three-second delay between engine cutoff and activation of the destruct charges so as to give the LES time to pull the capsule to safety...
Nine LV-3Bs were launched, two on uncrewed suborbital test flights, three on uncrewed orbital test flights, and four with crewed Mercury spacecraft. Atlas LV-3B launches were conducted from Launch Complex 14 at Cape Canaveral Air Force Station, Florida...