The rocket propulsion: new technological horizons, well-known difficulties Since the 40s of the 20th Century, humanity is using the missile technology to the nearly unlimited movement in three dimensions. As a powerful weapon they ensured the German army for months a military superiority in Service of scientific research, it revolutionized the exploration of space. By the detonation of some scientific and technological barriers, the world war of missiles in a new age was promoted.
operating principle of a rocket is ideally as a possible drag-free flight body moved a missile to the physical recoil law through the room. The basic principle can be offset by the momentum of two of the other repulsive body to explain: When a mass thrown off in one direction, providing a pulse, while the repulsive O BJECTS get a Against impulse in the other direction causes. For example, a moving vessel gives the momentum by returning the water pushes the water or put a counter-impulse. The law can be illustrated in a fluid picture:
The physical laws are in a simple fluid picture (two pots with water and a hose) shows representative. The widths of the vessels represent the masses, the filling levels above and below the black "zero line" set the Abstossgeschwindigkeiten the moving bodies dar. The greater the impulse (product of velocity times Mass) in a direction that works, the greater the pulse counter in the other direction (in the picture is colored blue).
The rocket engine is the only technology to get around in empty space. The pulse can be done by mass shift on both sides, according to the principle of a water rocket; The body pushes a portion of its mass. Pulse can also be generated by a pressure (1 Pa = 1 kg / m ^ 2), which drives away the object, without affecting the rejection of a mass is relevant. The latter method is much more efficient and is usually applied. As rocket engines do not work with air displacement, we construct rockets as aerodynamic, with a low drag coefficient (drag coefficient).
historical development
Necessity is the mother of invention: While in Germany as early as the mid-30 he was years ago a development program funded for space have been in this field only achieved tangible progress, as the problems had already arrived. The come under fire Germany needed a powerful weapon with which they could counter the number of moderately superior enemies without needlessly sacrificing their own nationals. Thus, a whole series of unmanned missile was developed.
The cruise missile Fieseler Fi 103:
He was colloquially as "retaliation weapon (V1)" well-known predecessor of the modern rocket. This unmanned flying object is not necessarily a rocket in the strict sense, since this device was able to fly by or under the influence of air resistance, so they needed to start a ramp to produce under their wings the appropriate air traffic. Technically, however, was steering the V1 is an important milestone in the development of today's rocket: The primitive autopilot was already able to meet the objective approximately.
works essentially the autopilot with a gyroscope (gyro compass, which is independent of the geomagnetic field at the axis of rotation of the earth-oriented by the law of conservation of angular momentum (kg * m ^ 2 * s ^ -1)). Moreover, an anemometer Zählpropeller (the distance flown determined by the air flow) on the front attached to the tip of the missile.
provides the thrust behind the top-mounted Verpuffungsstrahltriebwerk a useful purpose for such low-cost version of the "normal" aircraft engine. The hull of the cruise missile, there are two 150-bar compressed air-filled balls (in the picture to see behind the wing) which controls the combustion process in engine consent obtained: In front blinds closed, the fuel-air mixture is ignited by a spark plug and directed by the expanding gas to back through the exhaust nozzle. After this procedure reduces the excess pressure in the engine and speed reasons, it increases the front, which opens the blinds and the inside again provides an automated air traffic. Objects that are fired from a carrier aircraft can therefore dispense with the pressure vessel.
The Fieseler Fi 103 was developed in 1942 by German weapons technicians and aviation. Propaganda Minister Dr. Goebbels issued this flying bomb the populist Name "Vengeance Weapon", as they came in response to the bombing of Hamburg harbor against British troops in use. was introduced in 1943, the A4 rocket as a second retaliatory weapon, they decided on the abbreviations V1 and V2.
The approximately 2,200-pound Fi 103 reached a speed of 574 km / h, 3 km altitude and a range of 370 km. The autopilot provides an accuracy of 12 km. The aircraft was equipped with 847 kg Amatol (very effective mixture of TNT and fertilizers).
Modular Series:
The real breakthrough in missile technology was developed shortly after the development of the "V1" in the northern German Peenemünde. After the aggregate models 1,2 and 3, which did not meet the desired requirements of the A4 as the whiz kid "Vengeance Weapon 2" was introduced. This is one of the most technologically advanced missiles, which have been built so far.
drive
for the rocket engine has an explosive mixture of 75% ethyl alcohol and 25% oxygen are joined together before it ignited in the combustion chamber and the exhaust nozzle is ejected. This requires a pump, which promotes a second 150 l of liquid. This pump is driven at a high-pressure turbine by the decomposition of calcium permanganate and hydrogen peroxide. Hydrogen peroxide (H2O2) must be transported by cooling with compressed nitrogen. (This process is known from the U-boat technology: 2 H2O2 -> 2 H2O + O2 + heat). This mixture is burned, finally, in the nozzle creates a temperature of 2,700 ° C, so the combustion chamber walls must be cooled with alcohol channels. Effect obtained there as an over pressure of 18 bar, which causes a thrust of 270N, 300N, even in space, an even more topical today Value. be
navigation
On failure of the former radio and computer science technology had initially committed remote control trials as "unfeasible" explains. Therefore, this missile is equipped with an autopilot (attitude control) from working with top management and Schaltuhrtechnik. The centrifugal control consists of rotating disks and uses the principle of conservation of angular momentum, which states that each rotating body strives to maintain the rotation. Thus, the unmanned device are sent specifically to his journey. The switch is intended that these centrifugal control 3-4 seconds after the vertical Launch of the rocket in the direction so far, tends to the unit takes up the desired trajectory.
control and trajectory correction
When trying a pencil on its tip on a finger balancing aside, one could imagine that occur kinematic problems in a rocket launch. Even if a missile is designed as symmetrically as possible, its trajectory is deflected by external influences quickly, which must be corrected by constantly.
Once the aircraft by its speed a sufficient flow of air strips, the rudder can be moved to the tail wings by servo motors. In the initial phase, when the flying object has no sufficient speed, the 4 gas thruster (shown colored red) take on the flight path corrections.
material claims
The 14 m high, 12.5-ton floor-to-ground missile in the initial phase accelerated to over 1,150 m / sec, or around 3,700 km / h, until it is over 100,000 m in the universe is. There she bows her bow back toward Earth and the aim of the enemy country in the fall flight, in which they have a speed of Mach 5 (about 5,000 km / h). The material must be on the one hand because of flown height differences a pressure and temperature difference of 100,000 Pa, and 300 ° C, and because of the entry speed in the troposphere, can at the result from the air friction on the sheath temperature of 600 ° C, can take it. Even if the covering is made of solid steel, the liquid tank bewandet twice and the whole building is equipped with a cooling system that allowed explosives that may explode in less than 200 ° C can not be carried. So the A4/V2 has Amatol 1,000 kg, which in this severe impact leaves behind indelible marks. not
completed projects
While the mass production of the successful A4 from 250 to 500 units per month would have to be increased, were in the German space station in Peenemünde already other projects planned and tested. After the dropped projects were A5-A7 to A8. A9 and the A10 to be effective. However, these space bodies were not realized because of the war for the Germans becoming uncomfortable situation, that they were no longer beyond the planning and testing phases.
The A8 would be a booster rocket for a satellite has become the long-range radio link would have allowed for flying objects. There would be the A4 (V2) has been restricted to the radio-controlled precision autopilot replaced. Next we dreamed of a global network of satellite system, yielding (A10 would be through the carrier rocket was launched into space), the intercontinental missile A9 would have directed to your destination. The A9/10 would then have the nickname 'America Rocket' to get, as this would have been able to meet the military port of New York. The A8 had the satellite (geostationary-orbit) must carry at 36,000 km altitude, so-called "Low-earth-orbit" systems with horizontally moving bodies were not planned.
Future Entwicklug
Whether GPS, telephone and TV transmission via satellite or the observation of space with telescopes and space probes-Man is now practiced, the space technology for economic, to use military and scientific purposes. What has been proven painfully good 70 years ago seems now to be playful manageable.
If, however, regard the other day as the British astrophysicist Stephen Hawking published thesis that man to life calls from outside of the earth seems obvious how much the technology is still in its infancy. According to the statement of the physics Prfessors man must in the next 200 years, be prepared to remove the long term from the earth and colonize other planets, if he wants to survive long term. The tight schedule of 200 years, it is based on the end sympathetic to natural resources and growing environmental problems. could have never received a species in the long run if they are not spreading: The basic idea of this assertion seems logical. Is also the man no new habitats, he also will remain one day only in fossil From.
This aspect has the human race barely moved from the base of space development. The new horizons that space has been delivered to us, has so far only made known to us that we have to deal still with initial problems.
Sources:
-quarterly magazine for free historical research, issue 4 / 1999, Castle Hill Publishers, report on innovation from Werner von Braun
- luftarchiv.de; about aviation and weapons technology
- published information of the Imperial War Museum, London
Pictures:
Stephan Riediker, London, 2010
