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Atlas A

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Atlas A/B/D Test missiles Atlas A and Atlas B; Atlas D-Mercury Credit: © Mark Wade

AKA: B-65;PGM-16A;SM-65A;WS 107A-1;X-11. Status: Retired 1958. First Launch: 1957-06-11. Last Launch: 1958-06-03. Number: 8 . Thrust: 1,334.50 kN (300,008 lbf). Gross mass: 81,647 kg (180,000 lb). Height: 28.00 m (91.00 ft). Diameter: 3.05 m (10.00 ft). Apogee: 120 km (70 mi).

Maximum range: 900 km (550 mi).

Stage Data - Atlas A

• Stage 1. 1 x Atlas A. Gross Mass: 81,647 kg (180,000 lb). Empty Mass: 7,230 kg (15,930 lb). Thrust (vac): 1,517.412 kN (341,128 lbf). Isp: 282 sec. Burn time: 133 sec. Isp(sl): 248 sec. Diameter: 3.05 m (10.00 ft). Span: 4.90 m (16.00 ft). Length: 23.17 m (76.01 ft). Propellants: Lox/Kerosene. No Engines: 2. Engine: XLR-89-1. Status: Out of Production.

Historical Essay © Andreas Parsch

Convair B-65-SM-65-CGM-16-HGM-16 Atlas

The Atlas was the first Intercontinental Ballistic Missile (ICBM) deployed by the USA. Its descendents are still in use today as civilian and military space launch vehicles.

The Atlas development can be traced back to the days immediately after World War II, when captured German rocket and missile technology supported many new missile research studies. In April 1946, Consolidated-Vultee (later Convair) began project MX-774 to study long-range ballistic missiles. The studies led to a test rocket, designated RTV-A-2 Hiroc, which was to pioneer several new design techniques which would later be used in the Atlas. The Hiroc featured a gimballed rocket nozzle to steer the vehicle by thrust-vectoring instead of weight- and drag-increasing control fins, and had a separable nose cone for the payload. The most radical feature of the RTV-A-2 was its internal pressure stabilized flight structure. The missile's skin was very thin, and was inflated by internal pressure like a balloon. This significantly reduced the empty weight of the vehicle. However, it also made the missile rather fragile, because a single hole in the skin would lead to the collapse of the whole structure, just like a limp balloon. Because limited funding allowed only to pursue the most promising missile projects, and long-range ballistic missiles were deemed to be too far in the future, MX-774 was cancelled in June 1947. However, Convair was allowed to complete three Hiroc vehicles, and the first of these flew in July 1948. All three flights were only partially successful but helped a lot to validate the new design concepts.

After the cancellation of MX-774, Convair continued low-key internal studies on ballistic missiles, developing the idea of the "one and one half" stage rocket. In this type of design, both booster and sustainer engine(s) would ignite at lift-off, and the boosters would be dropped later in the flight. This circumvented the difficulty of having to ignite the sustainer at high altitude, which was then considered a potential problem. When military funding sharply increased after outbreak of the Korean War, Convair was awarded a contract for the long-range ballistic missile project MX-1593 in January 1951. Later in 1951, the USAF decided to assign aircraft-like designations to its guided missiles, and the designation B-65 was assigned to the MX-1593 missile (named Atlas by this time).

In 1953 Convair had completed the initial design studies. The Atlas was to be a huge 27 m (90 ft) long, 3.6 m (12 ft) wide rocket, with five engines producting 2700+ kN (600000+ lb) of total thrust. The size was deemed necessary to launch the expected very heavy (65 ton) thermonuclear warhead to intercontinental range. Because of the limited accuracy of then available intercontinental guidance systems, a megaton-class thermonuclear warhead was necessary for the Atlas to be effective against hardened targets. A ten-year development program was approved, with an initial operational deployment planned for 1963. To minimize risk, it was decided to develop a single-engine test vehicle first, designated X-11, followed by a three-engine X-12 test vehicle and an XB-65 five-engine strategic missile prototype.

In 1954, the H-bomb tests in the Pacific showed that the warhead for the Atlas could be made significantly smaller and lighter than expected. Therefore, the five-engine XB-65 design was cancelled and replaced by a much smaller three-engine design. The booster engines were North American (Rocketdyne) LR89, and the sustainer engine was a Rocketdyne LR105 enigne, both fueled with RP-1 (kerosene) and liquid oxygen. Two small Rocketdyne LR101 vernier engines were used for fine-tuning thrust and directional control. The whole Atlas propulsion system was known as MA-2. In 1955, in the light of discovering Russian ICBM activities, the Atlas development was accelerated, and it was approved to flight test preliminary prototype models which lacked some feartures of the planned production missile. The XB-65A Atlas A had only booster engines, and a dummy warhead. In August 1955, the USAF dropped all aircraft-like designations for guided missiles, and the Atlas became the SM-65.

On 11 June 1957 the first attempt to fly an XSM-65A was made, but due to a booster malfunction the missile had to be destroyed a few seconds after lift-off. The first successful Atlas A flight to the full range of 1100 km (600 nm) was the third one, on 17 December 1957. Atlas A testing was completed in June 1958.

Photo Gallery

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WS-107 WS-107 Concept 2. First mock-up of the Atlas missile in the three-chamber configuration. Credit: Ronald Wade

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• Atlas booster propulsion system work begins. - . Nation: USA. Work on MA-2 propulsion system for Atlas by Rocketdyne was begun, drawing upon the experience in developing the regeneratively cooled chamber developed for the Navaho..

• Ramo-Woolridge contracted for Atlas systems integration. - . Nation: USA. Ramo-Wooldridge given letter contract as Technical Director and Systems Integrator for Atlas program.

• Schriever named head of Atlas program. - . Nation: USA. Related Persons: Schriever. Brigadier-General Bernard A. Schriever, ARDC, assigned to head Atlas program.

• Scientific Advisory Board recommendations rejected. - . Nation: USA. Scientific Advisory Board recommendations differing from Teapot Committee rejected.

• First USAF WDD Facility - . Nation: USA. Inglewood "Schoolhouse" WDD facility established.

• Atlas further reduced in size - . Nation: USA. Atlas size reduced from 12-foot to 10-foot diameter, with 3 large engines.

• Atlas full-scale development - . Nation: USA. First major Atlas WS107A1 development and construction contract awarded Convair; CEP 2-3 NM, IOC by 1960-62.

• Atlas publicly announced. - . Nation: USA. USAF announced Atlas ICBM under construction by Convair..

• Atlas fabrication begins - . Nation: USA.

• Contract for 12 propulsion systems for Atlas A. - . The Air Force awarded the Rocketdyne Division of North American Aviation a contract to fabricate and deliver 12 rocket engine propulsion systems for the Series A Atlas flight test missiles..

• Atlas given top development priority. - . Nation: USA. USAF Chief of Staff, Nathan F. Twining, reported that ICBM's were receiving priority in the AF program because of known Soviet progress. Navaho, Snark, and Atlas programs accelerated..

• New WDD complex - . Nation: USA. New WDD complex activated on Arbor Vitae Blvd. in Los Angeles.

• Atlas program assigned top priority in the nation - . Nation: USA. Atlas program assigned top priority in the nation (was highest priority only for AF).

• Complete Atlas booster propulsion package fired for the first time. - . North American Aviation test fired the complete two-engine, 270,000-pound thrust Atlas booster propulsion package for the first time..

• Atlas production plant at Kearney Mesa - . Nation: USA. New Astronautics plant announced—$20 million funding by General Dynamics, with the Air Force to match, for tooling and special equipment.

• Convair announced as the prime contractorfor the Atlas - . Nation: USA. The Air Force disclosed that a $41 million guided missile production facility would be built at Sorrento, California, for the Atlas launch vehicle. Convair was announced as the prime contractor..

• First Atlas production engine delivered. - . North American Aviation delivered the first production type, Series A XSM-65 Atlas engine to Convair. The early Series A booster engines had a nominal thrust of 270,000-pounds..

• Atlas ICBM first test firing - . Nation: USA.

  First captive Atlas first test firing. The 'battleship' missile was installed at test stand 1-4, Edwards Air Force Base. The test was a failure due to inadvertant closure of the fuel prevalve, leading to duct collapse, and a turbine overspeed cutoff. No damage was sustained and the first successful firing came the next day. Atlas, First successful captive test firing, June 22, 1956, Edwards Rocket Base, duration - 4 seconds. Successful.

• Atlas 1A delivered - . Nation: USA. Atlas missile 1A was conditionally accepted by the Air Force and delivered to the Convair Sycamore Canyon Test Site for checkout prior to captive testing..

• Atlas missile 2A delivered to Edwards AFB - . Atlas missile 2A was accepted by the Air Force and delivered to Edwards AFB, Test Stand 1-A, for checkout prior to captive test firings scheduled for early 1957..

• Atlas first flight test vehicle delivered - . Atlas missile 4A, the first flight test vehicle, was delivered to the USAF at Convair's San Diego plant. It was then transported by truck to the Missile Test Center in Florida..

• Scheduled design complete (95%) for Atlas A-series missiles - . Nation: USA.

• Atlas 1A destroyed in test. - . Atlas missile 1A made its first captive test firing at Convair's Sycamore Canyon captive test facility. It burned on second run at S-l with stand damage.

• First flight Atlas missile delivered - . Nation: USA. First flight Atlas missile, 4A, delivered, and shipped to AMR.

• First flight Atlas missile erected - . Nation: USA. Atlas 4A erected on AMR LC-14.

• WDD renamed Ballistic Missiles Division (BMD) - . Nation: USA.

• Research and development test - . Nation: USA. Agency: USAF. Apogee: 3.00 km (1.80 mi).

  The first Atlas Series A flight test missile (4A) had to be destroyed shortly after launch from Cape Canaveral due to a booster engine shutdown and loss of thrust. From a technical standpoint, however, this first booster-only launch successfully demonstrated the launching mechanism, structural integrity of the airframe, subsystems performance, and operating procedures for launch crew personnel. First test flight of prototype WS-107A Atlas was detonated by command signal at 10,000 feet following a failure in the booster fuel system. The 23-second flight was considered a partial success.

• Research and development test - . Nation: USA. Agency: USAF. Apogee: 4.00 km (2.40 mi).

  The second Atlas flight test missile (6A) was destroyed 32 seconds into the flight because of an engine shutdown. Atlas was again destroyed by command signal at three minutes into flight following a failure in the booster fuel system. The 50-second active flight was considered a partial success.

• Research and development test - . Nation: USA. Agency: USAF. Apogee: 120 km (70 mi).

  The third flight test missile (12A) became the first successful Atlas Series A missile flight. A short-range, booster-only flight was completed with the booster impacting 575 miles down range from Cape Canaveral. During the flight, all systems performed satisfactorily. First successful test firing of USAF Atlas ICBM, the missile landing in the target area after a flight of 600 miles.

• Research and development test - . Nation: USA. Agency: USAF. Apogee: 120 km (70 mi). A successful limited flight was made by the fourth Atlas fired from Cape Canaveral..

• Research and development launch - . Nation: USA. Agency: USAF. Apogee: 120 km (70 mi).

• Research and development launch - . Nation: USA. Agency: USAF.

• Research and development test - . Nation: USA. Agency: USAF. Apogee: 100 km (60 mi). USAF Atlas A ICBM was flown from Cape Canaveral, Fla., to the impact area some 600 miles away..

• Research and development test - . Nation: USA. Agency: USAF. Apogee: 120 km (70 mi).

  The final Series A Atlas missile (16A) was launched from Cape Canaveral. Of the eight research and development launches, five had been failures, but each had provided vast quantities of important data. Last Atlas A flight, considered fully successful. Four of the eight flights were considered successful.