A Michigan Tech researcher has created a new computational model of an electrospray thruster using ionic liquid ferrofluid that could someday propel small satellites through space.
According to mechanical engineering doctoral candidate Brandon Jackson, the electrospray makes use of spiky, needle-like jets of fluid to push spacecraft.
More than 1,300 active satellites orbit the Earth. Of these, small satellites are now capable of performing missions once alloted to much larger and more expensive spacecraft, all thanks to advances in satellite computational and communications systems.
However, these tiny vehicles still need a more efficient way to maneuver in space. Scaled-down plasma thrusters, like those deployed on larger-class satellites, do not work well. A more promising method of micropropulsion is electrospray.
Electrospray involves microscopic, hollow needles that use electricity to spray thin jets of fluid, pushing the spacecraft in the opposite direction. But the needles have drawbacks. They are intricate, expensive and easily destroyed.
To solve this problem, Michigan Tech’s Space Systems professor L. Brad King created a new kind of microthruster that assembles itself out of its own propellant when excited by a magnetic field. The tiny thruster requires no fragile needles and is essentially indestructible.
King’s early work with the ferrofluid sample was pure trial and error; the results were good, but the physics were poorly understood. That’s when the Air Force Office of Scientific Research (AFOSR) gave King a contract to research the fluid physics of ferrofluid.
Working in King’s Ion Space Propulsion Laboratory, Jackson conducted an experimental and computational study on the interfacial dynamics of the ferrofluid, and created a computational model of ionic liquid ferrofluid electrosprays.
Thanks to Jackson’s creation, the team were able to gain a much better understanding of the relationships between magnetic, electric and surface tension stresses. Some of the data gathered through the model surprised them.
“We learned that the magnetic field has a large effect in preconditioning the fluid electric stress,” Jackson says, explaining this discovery might lead to a better understanding of the unique behaviors of ferrofluid electrosprays.
Image credits and excerpts: Michigan Technological University