Первая американская межконтинентальная баллистическая ракета "Атлас"

First American operational intercontinental ballistic missile

The SM 65 Atlas was the first operational intercontinental ballistic missile (ICBM) developed by the United States and the first member of the Atlas rocket family. It was built for the U. S. Air Force by the Convair Division of General Dynamics at an assembly plant located in Kearny Mesa, San Diego. Development dates to 1946, but over the next few years the project underwent several cancellations and re starts. The deepening of the Cold War and intelligence showing the Soviet Union was working on an ICBM design led to it becoming a crash project in late 1952, along with the creation of several other missile projects to ensure one would enter service as soon as possible. The first test launch was carried out in June 1957, which failed. The first success of the Soviet R 7 Semyorka in August gave the program new urgency, leading to the first successful Atlas A launch in December. Of the eight flights of the A model, only three were successful, but the later models demonstrated increasing reliability and the C model was cleared for use. Atlas C was declared operational in September 1959. Even at that time it was considered less than ideal as it had to be fuelled immediately before launch and thus had very slow reaction times. The Air Force still saw its strategic bombers as its primary force and considered Atlas as a last ditch weapon that would ensure a counterattack in the case the Soviets attempted a sneak attack on the US bomber bases. The initial versions were stored at ground level and thus subject to attack by Soviet bombers, which greatly reduced their suitability for this role. Starting with the F models they were stored in underground silos that offered some protection from air attack. New designs, especially the Minuteman, rendered Atlas obsolete and it was retired from the ICBM role by 1965. These disadvantages had no bearing on its use for space launches, and Atlas derived launch vehicles served a long history as launchers. Even before its ICBM 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. Mergers led to the acquisition of the Atlas Centaur line by the United Launch Alliance. Today ULA supports the larger Atlas V, which combines the Centaur upper stage with a new booster. Until 1995, many retired Atlas ICBMs were refurbished and combined with upper stages to launch satellites. At the time, the smallest atomic warheads were all larger than the maximum theoretical payloads of the planned long range missiles, so the contract was canceled in 1947, but the Army Air Forces allowed Convair to launch the three almost completed research vehicles using the remaining contract funds. The three flights were only partially successful, but did show that balloon tanks and gimbaled rocket engines were valid concepts. A second development contract was awarded to Convair on 23 January 1951 for what was then called MX 1593, with a relatively low priority. Atlas development was tightly controlled by the Air Force's Western Development Division, WDD, later part of the Air Force Ballistic Missile Division. Contracts for warhead, guidance and propulsion were handled separately by WDD. 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. The missile was originally designated as the XB 65 experimental bomber; in 1955 it was redesignated SM 65 ("Strategic Missile 65") and, from 1962, it became CGM 16. This letter "C" stood for "coffin" or "Container", the rocket being stored in a semi hardened container; it was prepared for launch by being raised and fueled in the open. The Atlas F (HGM 16) was stored vertically underground, but launched after being lifted to the surface. The penetrating lubricant WD 40 found its first use as a corrosion inhibiting coating for the outer skin of the Atlas missile.

The Atlas's complicated, unconventional design proved difficult to debug compared with rocket families such as Thor and Titan which used conventional aircraft style structures and two stage setups and there were dozens of failed launches during the early years. After watching Atlas Serial 7D explode shortly after its nighttime launch, Mercury astronaut Gus Grissom remarked "Are we really going to get on top of one of those things?" The numerous failures led to Atlas being dubbed an "Inter County Ballistic Missile" by missile technicians, but by 1965 most of the problems had been worked out and it was a reliable launch vehicle. Nearly every component in the Atlas managed to fail at some point during test flights, from the engine combustion chambers to the tank pressurization system to the flight control system, but Convair engineers noted with some pride that there had never been a repeat of the same failure more than three times, and every component malfunction on an Atlas flight was figured out and resolved. The last major design hurdle to overcome was unstable engine thrust, which caused three Atlas missiles (Serial 51D and 48D in 1960 and Serial 27E in 1961) to explode on their launching stands.

Atlas was unusual in its use of balloon tanks for the propellants, made of very thin stainless steel with minimal or no rigid support structures, as already pioneered by the Soviet R 5 first launched in 1953. Pressure in the tanks provides the structural rigidity required for flight. An Atlas rocket would collapse under its own weight if not kept pressurized, and had to have nitrogen in the tank even when not fueled. The rocket had two small thrust chambers on the sides of the tank called vernier rockets. These provided fine adjustment of velocity and steering after the sustainer engine shut down.

Atlas was informally classified as a "stage and a half" rocket, with a central sustainer engine and set of two booster engines that were all started at launch, each drawing from a single set of propellant tanks. Most multistage rockets drop both engines and fuel tanks simultaneously before firing the next stage's engines. However, when the Atlas missile was being developed, there was doubt as to whether a rocket engine could be air started. Therefore, the decision was made to ignite all of the Atlas' engines at launch; the booster engines would be discarded, while the sustainer continued to burn.

The booster engine consisted of two large thrust chambers. On the Atlas A/B/C, one turbopump assembly powered both booster engines. On the Atlas D, the booster engines had separate pump assemblies. Launcher variants of the Atlas often had performance enhancements to the engines.

The Atlas missiles A through D used radio guidance: the missile sent information from its inertial system to a ground station by radio, and received course correction information in return. The Atlas E and F had completely autonomous inertial guidance systems. The ground based guidance computer was a key part of the missile system, until guidance computers were miniaturized enough to be installed inside the missile. Isaac L. Auerbach designed the Burroughs guidance computer for the Atlas ICBM missiles. The Burroughs guidance computer was one of the first transistor computers. It processed 24 bit data using 18 bit instructions. A total of 17 of these ground computers were delivered. These same ground computers was later used for Atlas Able, Project Mercury, and other early spacecraft.

The warhead of the Atlas D was originally the G. E. Mk 2 "heat sink" re entry vehicle (RV) with a W49 thermonuclear weapon, combined weight and yield of 1.44 megatons (Mt). The W49 was later placed in a Mk 3 ablative RV, combined weight The Atlas E and F had an AVCO Mk 4 RV containing a W38 thermonuclear warhead with a yield of 3.75 Mt which was fuzed for either air burst or contact burst. The Mk 4 RV also deployed penetration aids in the form of mylar balloons which replicated the radar signature of the Mk 4 RV. The Mk 4 plus W 38 had a combined weight of The Atlas missile's warhead was over 100 times more powerful than the bomb dropped over Nagasaki in 1945.

The R 7 Semyorka was the first Soviet ICBM and similarly started all engines before launch to avoid igniting a large liquid fuel engine at high altitudes. However, the R 7 had a central sustainer section, with four boosters attached to its sides. The large side boosters required use of an expensive launch pad and prevented launching the rocket from a silo. Like the Atlas, the use of cryogenic liquid oxygen meant that the missile could not be kept in the state of flight readiness indefinitely and was largely useless for its intended purpose (military) and was similarly developed into a space launch vehicle, initially delivering Sputnik and Vostok into orbit. The Soyuz rocket is descended from the R 7 and remains in use today.

The Convair X 11/SM 65A Atlas/Atlas A was the first full scale prototype of the Atlas missile, first flying on 11 June 1957. It was a test model designed to verify the structure and propulsion system, and had no sustainer engine or separable stages. The first three Atlas A launches used an early Rocketdyne engine design with conical thrust chambers and only 135,000 pounds of thrust. By the fourth Atlas test, they were replaced by an improved engine design that had bell shaped thrust chambers and 150,000 pounds of thrust. There were eight Atlas A test flights, conducted in 1957–1958, of which four were successful. All were launched from Cape Canaveral Air Force Station, at either Launch Complex 12 or Launch Complex 14. The Atlas B was first flown on 19 July 1958. Of ten total flights, nine were sub orbital test flights of the Atlas as an Intercontinental Ballistic Missile, with five successful missions and four failures; the other flight placed the SCORE satellite into orbit. All launches were conducted from Cape Canaveral Air Force Station, at Launch Complexes 11, 13 and 14. Six flights were made, all sub orbital ballistic test flights of the Atlas, with three tests succeeding, and three failing. All launches were conducted from Cape Canaveral Air Force Station, at Launch Complex 12.

The SM 65D Atlas, or Atlas D, was the first operational version of the Atlas missile and the basis for all Atlas space launchers, debuting in 1959. Atlas D weighed (without payload) and had an empty weight of only ; the other 95.35% was propellant. Dropping the booster engine and fairing reduced the dry weight to , a mere 2.02% of the initial gross weight of the vehicle (still excluding payload). This very low dry weight gave Atlas D a range of up to 9000 mile (14484 km), or to orbit payloads without requiring an upper stage. It first flew on 14 April 1959. To provide the United States with an interim or emergency ICBM capability, in September 1959 the Air Force deployed three SM 65D Atlas missiles on open launch pads at Vandenberg AFB, California, under the operational control of the 576th Strategic Missile Squadron, 704th Strategic Missile Wing. Completely exposed to the elements, the three missiles were serviced by a gantry crane. One missile was on operational alert at all times. They remained on alert until 1 May 1964.

Ten flights of Atlas B occurred during the history of this variant. (SM 65B)Date Time(GMT) Pad Serial Apogee Outcome Remarks 1958 07 19 17:36 LC 11 3B Failure 1958 08 02 22:16 LC 13 4B Success 1958 08 29 04:30 LC 11 5B Success 1958 09 14 05:24 LC 14 8B Success 1958 09 18 21:27 LC 13 6B Failure 1958 11 18 04:00 LC 11 9B Failure 1958 11 29 02:27 LC 14 12B Success First full range test flight 1958 12 18 22:02 LC 11 10B N/A Success Placed SCORE satelliteinto x x 32.3° orbit 1959 01 16 04:00 LC 14 13B Failure 1959 02 04 08:01 LC 11 11B Success