For long-term operation in space, reliable electric rocket engines with a plasma flow rate of the order of one hundred and five meters per second or more should be used. Plasma engines began to be actively developed in the middle of the last century. And today this work continues.
Start of research
Our ancestors have long wanted to fly into space. Gas has been actively studied for a long time with the help of an electric discharge. It was placed in a glass container with electrodes. Then, with a decrease in pressure, rays emanating from the cathode appeared, which in fact, as it was later found out, was a stream of electrons.
And in 1886 it was discovered that, making holes in the cathode, other beams were drawn in the opposite direction from them - ionized gas atoms. But then, of course, they did not realize that they would be used to produce jet thrust.
During the Soviet Union, ion and plasma engines were developed in the laboratories of the physical and technical SOAN to apply these technologies in spacecraft. Work began in the fifties of the twentieth century. Two types of devices were discovered:
- erosion engine (pulse);
- stationary plasma engine (non-pulse).
It is these two types that are used to this day.
Erosion and stationary
The plasma engine, which is known today, functions due to the reactive power of the plasma jet from the nozzle. The plasma itself is produced by electrical discharge. For a simpler motor power source, a pulsed mode (erosive plasma engine) is selected. A capacitor acts as an energy source , the capacitance of which is 0.5 ΞΌF, and the voltage is 10 kV. Its charging comes from a transformer with diodes and a resistor.
Using such devices, small and precise impulse thrusts are formed that cannot be obtained with other types of rocket motors. Successful tests of pulsed plasma engines took place in 1964 at the Zond-2 space station.
SPD is a variant of an accelerator in an extended zone and with a closed drift of electrons. Such devices are able to work for a long period of time. Two xenon engines were first launched in 1972 aboard the Soviet Meteor.
Operating principle: prototype
The installation is as follows. The voltage for the capacitor is the gap between the collector conducting the current and the electrodes of the discharge chamber. When the voltage reaches the breakdown value, an electric discharge appears in the engine chamber. The air there is heated to ten thousand units and acquires a plasma state. The pressure increases sharply, and the jet of plasma flows out of the nozzle with great speed.
A rocket that is connected to the engine receives reactive power from the jet. For soft rotation, the rocket is attached with a ball bearing and, thanks to the counterweight, is balanced.
The most complex electrical node is a collector that supplies current. The gaps between the electrodes should be no more than half a millimeter. Then the power during transmission from the capacitor will almost not be lost, and additional friction will not be formed when the rocket begins to rotate.
The rocket itself and the entire plasma rocket engine can have different sizes, but the source power and capacitor size must be consistent. To calculate the basic components and design of the rocket, it is convenient to use the scheme after calculating by special formulas.
Experimental values ββon an example
For an example with a given voltage of six thousand watts and a capacitor capacity of 0.5 * 10 (-6) f, the result of the calculations will be the energy released in the engine chamber equal to 5.4 J. And if the temperature difference is 10,000 K, then the volume of the chamber get equal to half a cubic centimeter.
Then the elements of the electrical circuit will be:
- a 220 * 5000V transformer having a power of 200 watts;
- a wire resistor having a power of 100 watts.
This model has an operating voltage of more than a thousand volts, and therefore, you must be very careful when working with it and follow all necessary safety rules.
Safety rules for conducting an experiment
- The launch is carried out by one person. Others may stand at a distance of one meter from the appliance.
- All operations and touching the unit with your hands can only be done if it is disconnected from the power supply, having waited at least a minute after that. Then the capacitor has time to discharge.
- The power source must be located in a metal casing that is closed on all sides. During operation, it is grounded by means of a copper wire, the diameter of which should be at least one and a half millimeters.
Plasma engines for real rockets should have several thousand times more power! Maybe those who conduct experiments with small samples today will have to discover new possibilities and properties of plasma tomorrow .