Mark Megahan
The well paid Aerospace engineers at MIT came up with a fascinating new vehicle to get around with, on the moon. Why not take advantage of the Moon’s one-sixth gravity and natural ionic charge? They already built a hover-rover mock up and tested it in the lab. After they get the gear to Luna, it should fly like a Frisbee across the airless surface without using a whole lot of power to do it.
Vehicle floating in space
Lack of an atmosphere can be a good thing once in a while. Places like the moon, asteroids and other interesting but airless solar system real estate, have a tendency to build up an electric field. The one on the Lunar surface “is strong enough to levitate dust more than 1 meter above the ground, much the way static electricity can cause a person’s hair to stand on end.”
That should be useful for something, the team at MIT reasoned. Then they came up with a way to take advantage of it. Why not float a vehicle on the free charge?
They say that rocket scientists and brain surgeons really aren’t much smarter than the average. That’s why engineers at NASA and elsewhere didn’t come up with the idea. Now that it’s out there, they slap themselves upside the head for not thinking of it sooner. All they have to do is harness “this natural surface charge to levitate a glider with wings made of Mylar.”
The vehicle would be held up naturally by “the same charge as surfaces on airless bodies.” It works because “similarly charged surfaces should repel each other, with a force that lofts the glider off the ground.” They say that, at least for now, it’s better used on the smaller chunks of mass like “small asteroids.” Larger “planetary bodies would have a stronger, counteracting gravitational pull.” They’re pretty sure it will work on the Moon. They tested it.
What the team came up with was an idea for a levitating rover powered by “tiny ion beams to both charge up the vehicle and boost the surface’s natural charge.” That lets them work in higher gravity environments than asteroids.
“We think of using this like the Hayabusa missions that were launched by the Japanese space agency,” lead researcher Oliver Jia-Richards explains. “That spacecraft operated around a small asteroid and deployed small rovers to its surface. Similarly, we think a future mission could send out small hovering rovers to explore the surface of the moon and other asteroids.”
Very little power
Styled like a “flying saucer,” the craft is “designed to generate a relatively large repulsive force” between itself and the surface, “in a way that requires very little power.” Their study showed “that such an ion boost should be strong enough to levitate a small, 2-pound vehicle on the moon and large asteroids like Psyche.” They published all the details in the Journal of Spacecraft and Rockets.
“An asteroid’s terrain could be totally uneven, and as long as you had a controlled mechanism to keep your rover floating, then you could go over very rough, unexplored terrain, without having to dodge the asteroid physically.”
The cutting edge vehicle design uses miniature ion thrusters, called “ionic-liquid ion sources.”
The “microfabricated nozzles are connected to a reservoir containing ionic liquid in the form of room-temperature molten salt. When a voltage is applied, the liquid’s ions are charged and emitted as a beam through the nozzles with a certain force.” With a levitating rover, “you don’t have to worry about wheels or moving parts.”
To test their idea out, they made a working model. The problem is they have to do the test here on Earth so they used springs to counteract our 1G gravity. “The team initially modeled a small, disk-shaped rover with ion thrusters that charged up the vehicle alone.” They soon found it wasn’t enough. Back to the drawing board. “Then we thought, what if we transfer our own charge to the surface to supplement its natural charge?” it worked.
“By pointing additional thrusters at the ground and beaming out positive ions to amplify the surface’s charge, the team reasoned that the boost could produce a bigger force against the rover, enough to levitate it off the ground.” On the Moon, “a 50-kilovolt source” will achieve liftoff. “This kind of ionic design uses very little power to generate a lot of voltage. The power needed is so small, you could do this almost for free.”
