Summary:

Ferrofluids form spikes when exposed to a magnet, offering an alternative to the expensive, fragile needles researchers have been using to build tiny jet propulsion systems.

Ferrofluid
photo: Sarah Bird

Like a squid shooting a jet of water to propel itself forward, tiny satellites known as nanosatellites could someday expel fine streams of liquid to move from place to place above the Earth. Instead of using tiny needles to shoot the liquid, Michigan Technological University researchers have found a more elegant solution: ferrofluid, a magnetic liquid that forms itself into needles that can act in a similar way.

Ferrofluids remain flat until a magnet is applied, at which point they form spikes. The spikes remain in place even if the fluid is shaken or turned upside down. Even if one of the spikes is broken, ferrofluids are self healing, meaning the spike reforms. Needles, on the other hand, break irreversibly. Each nanosatellite, which measures just a few inches across, calls for a few hundred of them.

“Because they are so small and intricate, they are expensive to make, and the needles are fragile,” Michigan Technological University mechanical engineering professor Brad King said in a release. “They are easily destroyed either by a careless bump or an electrical arc when they’re running.”

Nanosatellites need to be somewhat rugged because they are shipped into space on rockets that could be carrying all sorts of cargo. They have to survive the journey into space and then traveling to their final destination above Earth.

King has applied for a patent and will continue researching nanosatellite applications for ferrofluids.

“First we have to really understand what is happening on a microscopic level, and then develop a larger prototype based on what we learn,” King said in the release. “We’re not quite there yet; we can’t build a person out of liquid, like the notorious villain from the Terminator movies. But we’re pretty sure we can build a rocket engine.”

Comments have been disabled for this post