Plasma engines: history, types, experience

For long-term work in space, reliable electric propulsion engines with a plasma outflow rate of about one hundred and five meters per second and more should be used. Plasma engines began to develop actively in the middle of the last century. And today this work continues.

Start of research

In space, our ancestors have long wanted to fly. 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, as the pressure was lowered, the rays emanating from the cathode appeared, which in fact, as it was later found out, was the flow of electrons.

And in 1886 it was discovered that, while making holes in the cathode, in the opposite direction from them stretched other rays - ionized atoms of gases. But then, of course, they did not know that they would be used to obtain reactive thrust.

During the Soviet Union, ion and plasma engines were developed in the laboratories of the physical and technical SOS to apply these technologies in spacecraft. Work began in the fifties of the twentieth century. Two types of devices were discovered:

• Erosion motor (impulse);
• Stationary plasma engine (non-pulse).

These two kinds are used to this day.

Erosion and stationary

The plasma engine, which is known today, functions due to the reactive force of the plasma jet from the nozzle. The plasma itself is formed by electric discharge. For a simpler motor power source, a pulse mode (erosion plasma motor) is selected. The energy source is a capacitor with a capacitance of 0.5 μF, and a voltage of 10 kV. Its charging occurs from the transformer with diodes and a resistor.

With the help of such devices, small and accurate pulsed thrusts are formed, which can not be obtained by operating other types of rocket motors. Successful tests pulsed plasma engines were held in 1964 at the space station "Zond-2."

SPD is a variant of the accelerator on an extended zone and with a closed drift of electrons. Such devices are capable of operating for a long period of time. Two engines on xenon were first launched in 1972 on board the Soviet "Meteor".

Principle of operation: prototype

The work of 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 value of the breakdown, an electric discharge appears in the motor chamber. The air there is heated to ten thousand units and acquires a plasma state. The pressure increases sharply, and the plasma jet flows at a great speed from the nozzle.

The rocket, which is connected to the engine, receives reactive force from the jet. To implement soft rotation, the missile is attached by a ball bearing and balanced by a counterweight.

The most complex elektrouznom is the collector, supplying current. The gaps between the electrodes should not be more than half a millimeter. Then the transmission power from the capacitor is almost not lost, and no additional friction will be formed when the rocket starts to rotate.

The rocket itself and the entire plasma rocket engine may have different sizes, but the source capacity and the capacitor size must be respected. To calculate the basic units and the design of the rocket, it is convenient to use the circuit after calculation by special formulas.

Experimental values by example

With an example of a specified voltage of six thousand Watts and a capacitor of 0.5 * 10 (-6) φ, the result is a calculation of the energy released in the engine chamber of 5.4 Joules. And if the temperature difference is 10000K, then the chamber volume It will be equal to half a cubic centimeter.

Then the elements of the electrical scheme will be:

• Transformer 220 * 5000V, having a power of 200 watts;
• Resistor wire, having a power of 100 watts.

This model has an operating voltage of more than a thousand volts, and therefore you need to be very careful when working with it and observe all the necessary safety rules.

Safety rules for the experience

1. Runs one person. Others can stand in the distance at a distance of one meter from the device.
2. All operations and touching the installation with hands can be done only if it is disconnected from the power supply, after waiting at least a minute after that. Then the capacitor will be discharged.
3. The power supply must be located in a metal enclosure that is closed on all sides. When working, it is grounded by means of a copper wire, the diameter of which must be at least one and a half millimeters.

Plasma engines for real rockets should have a power of several thousand times more! Maybe those who are now conducting experiments with small samples, tomorrow, will have to discover new possibilities and properties of plasma.