![]() On Mars, the molecules that make up the atmosphere are spaced further apart than in an atmosphere like Earth’s, since they are less dense. This very low pressure makes breakdown more likely. The Martian atmosphere is extremely thin, at the surface just about one percent of the pressure of Earth’s atmosphere at sea level. The impact liberates more electrons from CO2 molecules, which amplifies the current. Atmospheres can have free electrons as well, and the few free electrons in the Martian air feel the force of the electric field from the rotorcraft and crash into atmospheric carbon dioxide (CO2) molecules. Free electrons – those not bound to an atom – in an electrically conducting material such as a copper wire are responsible for the flow of electric current. The charge makes electrons respond to electric fields – attracted to a field generated by positive charge and repelled from a field generated by negative charge. Electrons are very small particles with negative electric charge. The team found that breakdown begins as an invisible “electron avalanche”. As charge builds to high levels, the atmosphere starts to conduct electricity, a process known as “atmospheric breakdown,” creating a population of electrons that form an enhanced electric current that acts to dissipate or offset the charge build-up on the rotorcraft. ![]() As the blades impact the grains, charge is transferred, building up on the blades and creating an electric field. They found that as the drone’s blades spin, they run into tiny dust grains in the Martian air, especially when the helicopter is near the surface and blowing dust around. Charge buildup also happens on terrestrial helicopter blades, especially in dusty environments, so the team also used interpretations and modeling of the charging from terrestrial helicopters as a basis for understanding the Mars case. The team applied laboratory measurements and used computer modeling to investigate how electric charge could build up on a drone’s rotor blades. The electrified balloon will attract the person’s hair causing it to lift toward the balloon– which indicates that the balloon has developed a large electric field from the triboelectric charging process. Triboelectric charging happens when friction transfers electric charge between objects, like when a person rubs a balloon against their hair or sweater. “The electric currents generated by the fast-rotating blades on drones are too small to be a threat to the craft or the Martian environment, but they offer an opportunity to do some additional science to improve our understanding of an accumulation of electric charge called ‘triboelectric charging’,” added Farrell. “NASA’s experimental Ingenuity helicopter does not fly during this time, but future drones could be cleared for evening flight and look for this glow.” “The faint glow would be most visible during evening hours when the background sky is darker,” said William Farrell of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, lead author of a paper on this research published Main Planetary Science Journal.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |