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2nd Atlas Launch-Blowup: "Flight Test Report of Atlas Missile 6A" 1957-09-25 Convair
🕑 Added 2020-09-17 20:12:01 +0000 UTCmore at http://quickfound.net/
SM-65 Atlas ICBM: Project Atlas contractor's report on the second flight test, in which the thrust section overheated and the Range Safety destruct command was sent at T+63 seconds.
Originally a public domain film from the US Government, 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/SM-65A_Atlas
Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/
The Convair SM-65A Atlas, or Atlas A was the first full-scale prototype of the Atlas missile, which first flew on 11 June 1957. Unlike later versions of the Atlas missile, the Atlas A did not feature the stage and a half design. Instead, the booster engines were fixed in place, and the sustainer engine was omitted. The propulsion system used on the initial Atlas As was an early version of the Rocketdyne MA-1 engines with conical thrust chambers that produced a mere 135,000 pounds of thrust, compared with the 360,000 pounds of the fully operational Atlas D...
On September 25, Missile 6A was launched. Aside from more instrumentation in the thrust section and the above-mentioned helium vent modification, it was identical to 4A and predictably met the same fate as once again, the thrust section overheated. Thrust levels in both engines dropped to only 35% at T+32 seconds and two seconds later, the propulsion system completely shut down. The Range Safety destruct command was sent at T+63 seconds. This time, overheating and high vibration levels had caused a LOX regulator to fail, resulting in gas generator flameout. After this debacle, the Air Force relented and accepted the need for an improved heat shield. Other modifications were made as well, including removal of the long skirt covering the boattail and engine nozzles. The gas generator vent pipe was changed to point outward and away from the missile instead of directly underneath it. The engine nozzles were covered with fiberglass insulation boots and aluminum plumbing in the Atlas changed to steel plumbing which had a greater heat tolerance. The autopilot received additional filters to dampen vibration levels.
The overheating problems had not shown up on the static firing tests of Missiles 1A-3A, but it was later revealed that the engineering crews at the Sycamore test stand had had the plumbing changed to steel because it reduced the risk of overheating compared with the aluminum plumbing on flight article missiles. The PFRF (Pre Flight Readiness Firing) tests conducted on 4A and 6A also would have caused exhaust gases to go up into the boattail, and thus they probably already had internal damage at launch...
http://en.wikipedia.org/wiki/SM-65_Atlas
The SM-65 Atlas was the first intercontinental ballistic missile (ICBM) developed and deployed by the United States. It was built for the U.S. Air Force by Convair Division of General Dynamics at the Kearny Mesa assembly plant north of San Diego, California. Atlas became operational as an ICBM in October 1959 and was used as a first stage for satellite launch vehicles for half a century. The Atlas missile's warhead was over 100 times more powerful than the bomb dropped over Nagasaki in 1945.
An initial development contract was given to Consolidated Vultee Aircraft (Convair) on 16 January 1951 for what was then called MX-1593, but at a relatively low priority. The 1953 testing of the first dry fuel H-bomb in the Soviet Union led to the project being dramatically accelerated. The initial design completed by Convair in 1953 was larger than the missile that eventually entered service. Estimated warhead weight was lowered from 8,000 lb (3,630 kg) to 3,000 lb (1,360 kg) based on highly favorable U.S. nuclear warhead tests in early 1954, and on 14 May 1954 the Atlas program was formally given the highest national priority... The first successful flight of a highly instrumented Atlas missile to full range occurred 28 November 1958. Atlas ICBMs were deployed operationally from 31 October 1959 to 12 April 1965...
Even before its military use ended in 1965, Atlas had placed four Project Mercury astronauts in orbit and was becoming the foundation for a family of successful space launch vehicles, most notably Atlas Agena and Atlas Centaur...
