Romanian engineers have developed a small plasma jet capable of blowing Martian dust from solar panels and other equipment that can be used by future missions.
The “plasma broom” solution developed by Ticoş and colleagues uses bursts of plasma jet produced by a simple plasma accelerator. When a large current is passed through two electrode plates separated by a field of rarefied gas, the voltage difference between the two electrodes ionizes the gas, creating the plasma. In the broom, this is done with a coaxial gun – the two metal electrodes are arranged as an inner rod within a hollow cylindrical shell. The discharge current flowing through the central rod electrode produces a magnetic field, which, together with the electric field, exerts a Lorentz force on the ionized gas that expels it. “The trick is that you need a quite high current in order to produce a reasonable magnetic field and this can be achieved more conveniently in a pulsed operation,” Ticoş explains. “For a fraction of a second (100 µs) the current is very high (several kiloamps) and the force pushing the plasma is quite strong.” During a pulse, the plasma is expelled at a very high speed – several kilometres per second – and so can simply blow dust away from an area two to four times bigger than the diameter of the jet.
An advantage of the plasma broom is that it uses low-pressure CO2 as the gas between the electrodes. This is particularly ideal for operation on Mars as the atmospheric pressure there is 150 times lower than on Earth and the atmosphere is 96% CO2. This means the gun will be able to function in “open” Martian atmosphere without the need for a pump or gas bottle. Ticoş and colleagues have also considered the energy required for the cleaner to function on Mars. This depends on the voltage the gun operates at and can vary between a few hundred to a few thousand Joules per pulse. “We did an energy budget estimate taking into account the solar irradiance on Mars,” says Ticoş, “and it appears perfectly feasible to fire a few shots even on a daily basis for cleaning the solar panels, which will boost considerably the energy production rate.”
Essentially, they are using ion engine concepts to create a can of dust-off, using the Martian atmosphere itself as the can.
Hat tip Mike Buford.