(SITRONICS Group)
Sitronics Group have started testing a plasma engine for small spacecrafts.
The engine will allow the nanosatellites to independently lower the altitude of the orbit at the end of their life.
Next year, two plasma-powered cubesats will go into low-earth orbit.
Usually, CubeSat nanosatellites do not have engines, so they are not able to controllably change their orbit.
After completing their work, they can stay on it for more than ten years, at the risk of colliding with other devices.
Finding a suitable propulsion system for nanosatellites that would allow them to perform complex orbital maneuvers is not an easy task due to limitations in their size, weight and power consumption, as well as due to safety requirements.
They eliminate the use of explosives and restrict the use of compressed gas cylinders, but for small satellites a plasma engine might well be suitable.
A plasma engine is a type of electric rocket engine. It has gas supplied to the working annular zone, the outer part of which is the anode; and the inner, located closer to the outlet, is the cathode.
When a constant voltage of hundreds of volts is applied to the anode and cathode, an ionizing discharge occurs in the working area and a plasma is formed.
Then this plasma, under the action of the Lorentz force, begins to move towards the exit from the working zone, creating thrust.
Typically, a plasma engine requires a large amount of energy to operate, but specialists from MEPhI University managed to get it to work from a small capacitor bank.
Their plasma propulsion system VERA (Volume-Effective Rocket-propulsion Assembly) weighs 0.4 kilograms, and its dimensions, taking into account fasteners and connectors, are 89 by 95 by 60 millimeters.
The working fluid in the engine is polyacetal plastic. It gradually burns out, turns into plasma and is thrown out of the engine, creating thrust.
The VERA rated thrust is assumed to be 20 micronewtons. If necessary (and if there is a reserve of electrical power), the engine can be boosted up to 50 micronewtons.
MEPhI and Sputniks have already started firing tests of VERA. Next year it will be tested on two CubeSat 3U nanosatellites in near-earth orbit.
The developers say that plasma engines will help nanosatellites lower their orbit at the end of their life, cutting the time to burn in the upper atmosphere by two to three times.
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