Engineers have envisioned a new concept for a rover that resembles a disk-shaped flying saucer and can float across the moon’s surface by utilizing the Moon’s natural charge.
As Earth’s companion lacks an atmosphere, it builds an electric field through direct exposure to the sun and surrounding plasma, which scientists say can be used for rover levitation on the Moon.
The moon’s surface charge is strong enough to float dust more than 1 m above the ground, just as static electricity can cause a person’s hair to rise, say researchers at the Massachusetts Institute of Technology (MIT) in the United States.
Previous studies have suggested that gliders could be built with wings made of Mylar – a material that holds the same charge as surfaces on airless bodies – as similar charges repel each other.
However, scientists also theorized that such designs based on ionic reinforcements would likely be limited to small asteroids, as the lift generated from this repulsion would be counteracted by the gravity of larger planetary bodies such as the Moon.
In the new feasibility study, MIT aviation engineers have shown that such an ion boost should be strong enough to hover a small vehicle of 1 kg on the moon and large asteroids like Psyche.
The concept vehicle that looks like a disc-shaped flying saucer and described in the journal Spacecraft and rockets, uses small ion beams to both charge the vehicle and boost the natural charge of the surface.
“With a hovering rover, you do not have to worry about wheels or moving parts,” Paulo Lozano, a co-author of the study, said in a statement earlier this month.
“An asteroid’s terrain could be completely uneven, and as long as you had a controlled mechanism to keep your rover afloat, you could go over very uneven, unexplored terrain without having to dodge the asteroid physically,” Dr. Lozano, director of MIT’s Space Propulsion Lab, added.
The Rover design consists of small, microfabricated nozzles connected to a reservoir containing ionic liquid in the form of a molten salt.
When a voltage is applied to the molten salt, the ions of the liquid are charged and emitted as a jet through the nozzles with a certain force, which helps the rover achieve lift, the researchers said.
The team’s mathematical models suggest that the idea could work and would provide enough momentum to get the rover off the ground.
In laboratory experiments, the researchers estimated the conditions necessary for a small palm-sized vehicle weighing about 60 grams to float.
Using these results, they have predicted that a small rover weighing about 1 kg could achieve levitation of about 1 cm from the ground, on a large asteroid such as Psyche, by using a 10-kilovolt ion source and about a 50 kilovolt source to get a similar lift on the moon.
“This kind of ionic design uses very little power to generate a lot of voltage. The power required is so small that you can do this almost for free,” said Dr. Lozano.
With greater excitement, researchers said the ion thrusters could generate more power to lift a vehicle higher off the ground. But they added that the models need to be revised to take into account how the emitted ions would behave at higher altitudes.
“We are thinking of using this as the Hayabusa missions launched by the Japanese space agency,” study lead author Oliver Jia-Richards, a graduate student at MIT, said in a statement.
“That spacecraft operated around a small asteroid and put small rovers to the surface. Similarly, we believe a future mission could deploy small hovering rovers to explore the moon’s surface and other asteroids,” Jia-Richards said.