From the Second World War to the space race
On 8 September 1944 a German V‑2 rocket hit Chiswick, West London. The V‑2 was a ballistic missile known to its engineers as Aggregate‑4. Nazi propaganda minister Joseph Goebbels announced it as Vergeltungswaffe‑2 or V‑2, the second in a series of Уvengeance weaponsФ, the first being a robot jet plane known as the V‑1. The V‑2 was fuelled by liquid alcohol and liquid oxygen (LOX), weighed 14 tons and carried 1 ton of high explosive.
The V‑2 was designed by a group of German scientists led by Wernher von Braun. As a youth von Braun had been inspired both by science fiction and by the theories of Professor Herman Oberth. Like other German scientists he had been impressed by the 1926 Fritz Lang film The Woman in the Moon and by OberthТs The Rocket into Planetary Space (1923). He joined a group of like‑minded enthusiasts who formed an amateur rocketry club, the Verein fuer Raumschiffahrt: VfR (Space Travel Association).
Inspired by OberthТs theoretical arguments, the Germans in the VfR conducted numerous static firings of rocket engines and launched a number of small rockets. Meanwhile, in 1931, the German Army inaugurated a modest rocket development program, hoping that rocketry could become an extension of long‑range artillery. The program employed several of the VfR members.
The German ArmyТs ordnance ballistic section was interested in long‑range bombardment weapons which were not forbidden to them by the Treaty of Versailles (1919). Under the terms of this Treaty, which had been concluded at the end of the First World War, GermanyТs military power was strictly limited, but in 1919 rockets had not been considered to be serious weapons so they werenТt forbidden.
Von Braun was encouraged to continue his studies, completing a degree in aeronautical engineering in 1932 and a Ph.D two years later. His thesis was on rocket engines and was classified as a military secret.
After the Nazi party gained political power in 1933, von BraunТs rocket team continued their research. While Germany rearmed itself von BraunТs rocket team developed larger, longer ranged liquid‑fuelled missiles. In 1939 the air force, the Luftwaffe, funded a joint service rocket research centre at Peenemunde and gradually overcame the basic problems of rocket engineering: flight stability, fuel management, steady combustion pressure, engine cooling and guidance. The commander of the army, the Wehrmacht, granted the Peenemunde centre additional funds and personnel so that they could produce a prototype operational missile, which should be able to carry 1 ton of explosives to a target 180 miles away. This was achieved on 3 October 1942. After an air raid (17 August 1943) on Peenemunde, production of the V‑2 was removed to a secret location in the Harz Mountains.
By January 1945 it was clear to the German rocket scientists that Germany would lose the war and von Braun called a meeting to discuss to which Allied power they should offer their expertise. He said, УLetТs not forget that it was our team that first succeeded in reaching outer space. We have never stopped believing in satellites, voyages to the moon and interplanetary travel.Ф
He organized the escape of his team and their technical archives to the advancing US forces and on 2 May 1945 they made contact. The Americans responded with an effort called Operation Paperclip. This secured the GermansТ technical archives and parts for 100 V‑2 rockets, which were taken to the USA.
The Soviets also recognised the value of German rocket designers and recruited some themselves, among whom was Hans Endert. He told Reg Turnhill, the BBC correspondent, after he heard that von Braun had gone over to the United States: УKnowing that the Americans knew everything, I had no scruples about helping the Russians because they offered me a decent salary and food rations which I could get nowhere else.Ф
The Soviets were aware that their former Allies had significant advantages in long‑range bomber aircraft, so to counter this they were interested in developing long‑range ballistic missiles. The Soviet leader, Joseph Stalin, imagined a more powerful version of the V‑2, armed with a nuclear warhead. They set up a German engineering team under Helmut Grottrup at a base north‑west of Moscow where they were to develop their own intercontinental ballistic missiles (ICBMs).
The Russians had their own tradition of the science and theory of rocketry. Their pioneer was Konstantin Tsiolkovsky. Tsiolkovsky had written a theoretical article called УExploration of Cosmic Space with Reactive DevicesФ in 1898 but it was not published until 1903. In it he suggested the use of liquid propellants for rockets in order to achieve greater range and went on to state that the speed and range of a rocket were limited by the exhaust velocity of escaping gases. A substantial part of the article was devoted to a detailed description of the mechanics of putting a satellite into orbit.
The SovietsТ chief rocket designer was a Russian, Sergei Korolev; like von Braun, Korolev had served an УapprenticeshipФ in amateur and semi‑official rocket groups. By the late 1940s the Soviets had learnt all they could from their German captives and had solved the overheating problems which were inherent in high‑energy rockets, having to do this within the limits of Soviet metallurgy. They did this by creating an engine with four small, thickly walled combustion chambers Ц the RD‑107 engine which was fuelled by kerosene and liquid oxygen and produced 225,000 lb of thrust. It was capable of being the basic element of either an ICBM or the booster or launcher of a spacecraft.
The key to a long‑distance missile lay in TsiolkovskyТs concept of multiple stages: the first, heavy stage enabled the rocket to break free from the earthТs gravity. The lighter upper stages would accelerate it to the speeds necessary for intercontinental ballistic trajectory or orbital flight. Ideally the upper stage engines should be lighter with a higher thrust‑to‑weight ratio, but lighter upper stages were beyond Soviet technology. Korolev came up with a compromise which was within the SovietsТ capability.
The compromise was a composite rocket with Уstrap‑onФ boosters around a central УsustainerФ engine, the УstagingФ being parallel rather than vertical. At lift‑off all the rocketТs engines fired. The УstagingФ occurred as the engines ran out of fuel, and then fell away. KorolevТs rockets were often described as looking like a Уflared skirtФ. The Russians called it УSemyorkaФ (old number seven).
On 4 August 1949 the USSR exploded its first nuclear weapon on an Arctic test range, whereupon the US Army demanded a tactical (battlefield) nuclear missile.
Von BraunТs early years in the United States had been comparatively frustrating, his team having first been set up at Fort Bliss in West Texas under the authority of the US Army. The US Air Force had recently become independent of the US Army and wanted long‑range bombers to improve its strategic bomber force. Consequently, the United States was relatively disinterested in long‑range ballistic missiles. Von Braun was slowly developing a proposal for an expedition to Mars when the ArmyТs demand for a tactical (battlefield) nuclear missile became a priority. In 1952 the United States was developing a 10 megaton thermonuclear weapon but the УHФ bomb was too heavy for even the most powerful bomber the US Air Force possessed (the B‑36). In 1953 the Soviet Union exploded its own УHФ bomb which was lighter but less powerful. The US bomb tested at Bikini Atoll in 1954 weighed less than 10,000 lb, light enough to be delivered by an ICBM.
US development was concentrated on its own ICBM, the Atlas missile. Whereas the United StatesТ advantage in computers helped them to develop lighter warheads, the USSR lacked this expertise and their weapons remained heavy until the late 1960s.
KorolevТs team was moved to a new missile test range at Tyuratam and by 1955 they were involved in a crash program to get their ICBM design into production. The Soviet leader Mr Krushchev wanted the demonstration of their ICBM to coincide with the International Geophysical Year (IGY) in 1957. The IGY was supposed to be a year of international co‑operation in scientific fields including atmospheric science. If KorolevТs prototype could carry a 2‑ton thermonuclear warhead 4,000 miles (from the Soviet Union to the USA), it could carry a satellite into orbit.
The United States had worked out the cost of an earth satellite project, but it was rejected by the cost‑conscious Truman administration. The US Air Force continued to dominate US attempts at rocketry, their missiles being of the cruise missile type such as the УNavajoФ or the УMatadorФ. Von BraunТs (Army) team meanwhile had been moved to the Redstone Arsenal complex near Huntsville, Alabama where they had developed the V‑2 into the Redstone, which was a tactical, battlefield missile capable of delivering a nuclear warhead. The successor to the Redstone was to be the Jupiter, with a range of over 2,000 miles. In 1956 von BraunТs team used the JupiterТs Research & Development budget to fund a version of the Jupiter which would be capable of putting a satellite into orbit. The Jupiter CТs test flight delivered its nose cone 3,000 miles and reached a speed of 3,000 miles per hour, just less than the speed required for orbital injection. Meanwhile the Defense Department had decided that long‑range or strategic missiles were the responsibility of the Air Force, so the Army was forbidden to produce anything with a range of over 200 miles.
When the Soviet R‑7 (Semyorka) was tested on 3 August 1957, Soviet leader Mr Krushchev told the world that they had an operational ICBM. It was a bluff: it was a prototype. The USSR was not yet even developing ICBMs. On 4 October 1957 they launched Sputnik I.
On 5 October the New York Times reported: УThe Device is 8 times heavier than the one planned by US.Ф The analyst Harry Schwarz wrote: УThe competence in rocketry which that satellite shows is equally applicable to the field of weapons, particularly intercontinental ballistic missiles.Ф
President Eisenhower dismissed Sputnik as Уone small ball in the air, something which does not raise my apprehensions, not one iota.Ф
When the news of Sputnik broke, the US Defense Secretary, Neil McElroy, was visiting Redstone. Von Braun appealed to him: УFor GodТs sake! Turn us loose and let us do something. We can put up a satellite in sixty days.Ф УNo, Wernher, ninety days,Ф said a colleague.
The Soviets put up Sputnik II on 4 November 1957 and on 8 November the Army was given the authorization to make two satellite attempts. They succeeded in putting Explorer into orbit on 31 January 1958. Von Braun was summoned to Washington and his team handled the launch without him. The astronaut Buzz Aldrin wrote:
But if he couldnТt be at the Cape, von Braun made sure the Explorer launch was in the hands of his very best people. Willy Mrazek oversaw the Jupiter‑CТs propulsion system, just as he had the prototype A‑4 in Germany. Walter HaeussermannТs guidance and control laboratory had perfected the boosterТs inertial guidance, and Haeussermann was there that day for the final premission tuning. Ernst Stuhlinger, head of the research projects office, did the troubleshooting at the Cape. Overall command of the test launch was under Kurt Debus and his missile firing laboratory. Debus had supervised hundreds of V‑2 launches in Germany and New Mexico.
All day, strong winds delayed the launch as the Jupiter‑C sat on the concrete platform of Launch Pad 5, supported by a flame‑blasted Redstone gantry tower. Von BraunТs tone on the telephone showed how anxious he was, but he trusted his colleagues too much to interfere.
Then, at 10:48 pm, Debus completed the countdown and issued the ignition command from the firing bunker. The striped cylindrical payload package was Уspun upФ like a captive toy to stabilize the upper stage in flight. An orange glare ripped out as the Jupiter‑CТs Redstone first stage roared to life. For several seconds flame blasted sideways from the Jupiter as it stood stationary on the pad.
Then the rocket climbed away into the darkness. Two and a half minutes later the upper stages were separated by an automatic timer. For the next six minutes the payload coasted higher to an apex 225 miles above the Atlantic. Walter HaeussermannТs guidance package worked perfectly. The second‑stage cluster of solid rockets was brought parallel to the EarthТs surface by small thruster jets. Stuhlinger transmitted the command to ignite the second stage. After six and a half seconds, he ignited the third stage, comprised of three clustered Sergeants. Finally, he pressed the amber fourth‑stage ignition button and the single‑Sergeant satellite kicker motor ignited, accelerating Explorer to over 18,000 miles per hour, orbital velocity.
Medaris had insisted on a media blackout to prevent embarrassment if the mission failed and to keep down speculation about interservice rivalry. [Despite two Sputniks and the multiple Vanguard failures, the Navy was still in the satellite game.] No reporters were there to watch the delayed countdown and the spectacular launch. Residents of nearby Titusville and Cocoa Beach simply thought another secret missile was being tested. Two hundred and twenty‑five miles above West Africa, the tiny Explorer satellite glided silently through the day‑night terminator line and into brilliant sunlight. The satellite was the size of an overgrown titanium milk bottle and weighed only 10.5 pounds. To achieve orbit, ExplorerТs centrifugal energy would have to counter‑balance EarthТs gravity.
The first American listening station positioned to receive the radio beacon from a properly orbiting Explorer was the Goldstone tracking site in the California desert. Signals should have begun coming in at exactly 12:41 Pentagon. Pickering was on the phone with his people in California as the deadline passed. There was no signal from Explorer.
УWhy the hell donТt you hear anything?Ф Pickering yelled.
Secretary Brucker looked up from a table littered with coffee cups and overflowing ashtrays.
УWernher,Ф he asked, Уwhat happened?Ф
Von Braun watched the sweeping second hand on the wall of the communications room. If they didnТt get a signal in 10 minutes, he would have to consider the mission a failure.
At 12:49 am, Pickering whooped with joy, holding the receiver against his shoulder Goldstone had ExplorerТs signal. Von Braun beamed, then frowned. УShe is eight minutes late,Ф he muttered. УInteresting.Ф
A duty officer telephoned President EisenhowerТs vacation retreat in Augusta, Georgia. Ike excused himself from his late‑night bridge table to take the call, then recorded a radio announcement, reading calmly from a single sheet.У The United States has successfully placed a scientific Earth satellite in orbit around the Earth. This is part of our participation in the International Geophysical Year.Ф
Politicians in the opposing Democratic Party noticed the Уspace gapФ. In April 1958 President Eisenhower passed the National Aeronautics and Space Act of 1958 (Уthe Space ActФ) which declared that Уactivities in space should be devoted to peaceful purposes for the benefit of all mankind.Ф It further declared Уthat such activities shall be the responsibility of, and shall be directed by, a civilian agencyФ. The Act further established the National Aeronautics and Space Administration to be the Уcivilian agencyФ, which should seek and encourage, to the maximum extent possible, the fullest commercial use of space.
Its aims were to contribute materially to one or more of the following objectives:
(1) The expansion of human knowledge of the Earth and of phenomena in the atmosphere and space;
(2) the improvement of the usefulness, performance, speed, safety, and efficiency of aeronautical and space vehicles;
(3) the development and operation of vehicles capable of carrying instruments, equipment, supplies, and living organisms through space;
(4) the establishment of long‑range studies of the potential benefits to be gained from, the opportunities for, and the problems involved in the utilization of aeronautical and space activities for peaceful and scientific purposes;
(5) the preservation of the role of the United States as a leader in aeronautical and space science and technology and in the application thereof to the conduct of peaceful activities within and outside the atmosphere;
(6) the making available to agencies directly concerned with national defense of discoveries that have military value or significance, and the furnishing by such agencies, to the civilian agency established to direct and control nonmilitary aeronautical and space activities, of information as to discoveries which have value or significance to that agency;
(7) cooperation by the United States with other nations and groups of nations in work done pursuant to this Act and in the peaceful application of the results thereof;
(8) the most effective utilization of the scientific and engineering resources of the United States, with close cooperation among all interested agencies of the United States in order to avoid unnecessary duplication of effort, facilities, and equipment; and
(9) the preservation of the United States preeminent position in aeronautics and space through research and technology development related to associated manufacturing processes.
(e) The Congress declares that the general welfare of the United States requires that the unique competence in scientific and engineering systems of the National Aeronautics and Space Administration also be directed toward ground propulsion systems research and development. Such development shall be conducted so as to contribute to the objectives of developing energy‑and petroleum‑conserving ground propulsion systems, and of minimizing the environmental degradation caused by such systems.
(f) The Congress declares that the general welfare of the United States requires that the unique competence of the National Aeronautics and Space Administration in science and engineering systems be directed to assisting in bioengineering research, development, and demonstration programs designed to alleviate and minimize the effects of disability.
The head of NASA was the administrator, T. Keith Glennan, who asked for von BraunТs team to become part of the new agency. Whereas von BraunТs team and the Jet Propulsion Laboratory (JPL) had been responsible for putting Explorer into orbit, the United States put Explorer II and Vanguard I into orbit in 1958.
But Sputnik III weighed over 3,000 pounds. Krushchev mocked the tiny US satellites the Уsize of orangesФ.
It was clear to President Eisenhower that the Soviet successes were harming his administrationТs political reputation and he wanted the Air ForceТs Atlas to put a УspacecraftФ into orbit, insisting that the prototypes be launched by normal ICBMs first. The Atlas was the product of innovative US development, completely independent of the V‑2, but it wasnТt ready.
Buzz Aldrin described the launch of the Atlas prototype:
On December 18, 1958, the Air Force launched the Atlas prototype 10B from Launch Pad 11 at the Cape. Following the secret flight plan, the missileТs internal guidance system pitched the Atlas over parallel to the Atlantic at an altitude of 110 miles and the sustainer engine burned up the remaining tons of propellant. Five minutes later the entire 60‑foot, four‑ton aluminum shell was in orbit. The Defense Department proudly announced the success of Project SCORE (Signal Communications by Orbiting Relay Equipment). A tiny transmitter inside the empty Atlas shell broadcast tape‑recorded Christmas greetings from President Eisenhower to the world below. It was international showmanship worthy of Nikita Khrushchev.
President Eisenhower was informed by US intelligence services that the Soviets were trying to launch a Уnew communist manФ into space, so von BraunТs team suggested a sub‑orbital flight, using the tried and tested Redstone. It would be above the atmosphere but below orbital height.
The scheme was sold to the House of Representatives as the prelude to a rocket which could deliver troops to the battlefield. In August 1958 the President decided that NASA, not the military, should take responsibility for putting the first American into space. Abe Silverstein, the new director of space flight development chose УMercuryФ as the name for the program of manned space flight. At that time Buzz Aldrin and Ed White were US Air Force fighter pilots stationed in West Germany. Buzz Aldrin took a keen interest in spacecraft development. Aldrin:
The Space Task GroupТs first priority was to design an orbital vehicle that would protect a human passenger through all phases of a spaceflight УenvelopeФ: launch acceleration, weightlessness above the atmosphere, reentry deceleration with its furnacelike heat, and descent to parachute deployment at about 10,000 feet. NASA designers had two basic choices: the first was a winged spaceplane like the rocket‑powered X‑15 and the futuristic Dyna‑Soar space glider the Air Force wanted; the second was a wingless high‑drag, blunt‑body capsule. A capsule was the only design that met the weight limits imposed by the Atlas missile (the sole American booster capable of orbiting a manned spacecraft): approximately 3,000 pounds.
Buzz Aldrin described the design of the capsule:
Max Faget, LangleyТs ablest designer, and his team proposed a variation of the existing conical missile warhead that looked like an upside‑down badminton shuttlecock. The blunt bottom was a convex fiberglass heat shield that would point forward and disperse the reentry deceleration heat through a fiery meteor trail Ц a process known as Уablation.Ф A cluster of small solid retrorockets in the center of the heat shield would brake the capsule from its orbital speed and return it to Earth. The tiny cabin was a lopped‑off cone topped by a squat cylinder that held radio antennas and the parachutes. On top of this cylinder was a girdered escape tower powered by solid rockets that would pull the capsule away from a stricken booster (no one really trusted the Atlas), lifting it to a safe altitude for parachute deployment. The whole thing was a far cry from the sleek, winged spacecraft that many popular scientific magazines had imagined.
I remember the guys in my squadron in Germany commenting that the Mercury capsule looked more like a diving bell than an aircraft. The pilot would lie flat on his back on a form‑fitting couch. But even if the Mercury spacecraft wasnТt as fiercely beautiful as the supersonic fighters we flew, it was designed to УflyФ higher and faster than any jet plane, in an entirely new environment, space. There was no need for swept wings to provide lift, or a raked tail for control. The velocity imparted by the booster would lift the Mercury spacecraft far above the atmosphere.
Early in 1959, McDonnell Aircraft Corporation won the prime Mercury development contract, worth $18 million. Given Project MercuryТs priority status, McDonnell (which had spent a lot of its own money on preliminary designs) quickly produced a full‑scale mock‑up of the spacecraft.
ƒата добавлени€: 2015-05-13; просмотров: 1010;