Смотреть атлас (1961) в Full HD качестве ОНЛАЙН
Its purpose was to decide on the feasibility of building an ICBM large enough to carry a thermonuclear weapon. Von Neumann had long argued that while the technical obstacles were indeed formidable, they could be overcome in time.
Events were proving him right. The weapons had become smaller, and diode—transistor logic enabled the construction of compact guidance computers. The committee approved a "radical reorganization" and speeding up of the Atlas program. Atlas was informally classified as a "stage-and-a-half" rocket; Both the central sustainer engine and the set of two booster engines were started at launch, each drawing from a single set of propellant tanks.
At staging, the booster engines would be shut off and a series of mechanical and hydraulic mechanisms would close the plumbing lines to them. The booster section would then be released by a series of hydraulic clamps aside from the early test model Atlas B which used explosive bolts and slide off the missile. From there on, the sustainer and verniers would operate by themselves. Booster staging took place at roughly two minutes into launch, although the exact timing could vary considerably depending on the model of Atlas as well as the particular mission being flown.
A "stage" of a liquid propellant rocket is normally thought of as tanks and engine s together. The jettisoned engine, therefore, constitutes a "half stage".
The booster engine consisted of two large thrust chambers. On the Atlas D, the booster engines had separate pump assemblies. Later space launcher variants of the Atlas used the MA-5 propulsion system with twin turbopumps on each booster engine, driven by a common gas generator.
The boosters were more powerful than the sustainer engine and did most of the lifting for the first two minutes of flight. In addition to pitch and yaw control, they could also perform roll control in the event of a vernier failure. The sustainer engine on all Atlas variants consisted of a single thrust chamber with its own turbopump and gas generator, and two small pressure-fed vernier engines.
The verniers provided roll control and final velocity trim. The stage-and-a-half design mainly came about because of the Atlas design being finalized in the mid-1950s, at a time when engineers had not yet figured out how to air-start a rocket engine, so having all engines running at liftoff would avoid this problem the contemporary Soviet R-7 missile used a similar design for the same reason.
However, technology advanced quickly and not long after design work on Atlas was completed, Convair rival Martin proposed a solution to the air-starting problem, and their Titan I missile, developed as an Atlas backup, had a conventional two stage design. The first Atlas flown was the Atlas A in 1957—1958. 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.
This was followed by the Atlas B and C in 1958—1959. The B had full engines and booster engine staging capability. Finally, the Atlas D, the first operational model and the basis for all Atlas space launchers, debuted in 1959. E and F had fully self-contained inertial navigation systems INS and were nearly identical to each other except for interfaces associated with their different basing modes underground silo for F and the fuel management system.
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 to explode on their launching stands.
It was solved with the use of baffled injectors and other modifications which would prove vital to the Saturn V program, as it used a first stage engine that was loosely derived from the Atlas booster engines. By 1965, with the second-generation Titan II having reached operational status, the Atlas was obsolete as a missile system, and was gradually phased out in the mid-1960s.
Many of the retired Atlas D, E and F missiles were used for space launches into the 1990s. At the time the late 1940s , no missile conceived could carry even the smallest nuclear warheads then thought possible. The smallest atomic warheads were all larger than the maximum theoretical payloads of the planned long range missiles. The Convair team was led by Karel Bossart.
This was the MX-774 or Hiroc project. It was for this reason that 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. However they did show that balloon tanks, and gimbaled rocket engines were valid concepts. In the mid-1950s after practical thermonuclear weapons had been demonstrated and an independent design breakthrough drastically reduced the weight of such weapons, along with the CIA learning that the Soviet ICBM program was making progress, Atlas became a crash program of the highest national importance.
The missile was originally given the military designation XB-65, thus making it a bomber; from 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. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. August 2015 Learn how and when to remove this template message 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. Atlas was unusual in its use of balloon tanks for fuel, made of very thin stainless steel with minimal or no rigid support structures. Pressure in the tanks provides the structural rigidity required for flight. 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. When the Atlas missile was being developed, there was doubt as to whether a rocket engine could be ignited in space.
Rockets using this technique are sometimes called "stage-and-a-half" boosters. This is made possible by the extremely light weight of the balloon tanks. The tanks make up such a small percentage of the total booster weight that the weight penalty of lifting them to orbit is less than the technical and weight penalty required to throw half of them away mid-flight.
The R-7 had a central sustainer section, with four boosters attached to its sides. All engines were started before launch, eliminating the then unexplored task of igniting a large liquid fuel engine at high altitudes. Like the Atlas, the R-7 used cryogenic oxidizer and could not be kept in the state of flight readiness indefinitely.
Unlike the Atlas, the R-7 had large side boosters, which required use of an expensive launch pad and prevented launching the rocket from a silo.