UI duo's rocket may fly us to the moon
A new type of rocket propulsion system being developed by University of Illinois researchers generates thrust with a velocity fast enough to get you from here to Chicago in about five seconds.
Assuming a vehicle could actually move that fast (it can't), a state trooper didn't halt your progress along the way to write you a speeding ticket and you were traveling in an airless vacuum.
But speed traps aren't a problem in space, which also happens to be one big vacuum.
The same technology could be used to speed travels between Earth and the moon – the planned first stop on the way to a potential manned mission to Mars in coming decades – to Mars and elsewhere in space.
Moreover, the system has the advantage of burning comparatively little fuel for the thrust it generates, UI Professor Rod Burton said recently.
"The amount of fuel you need for each push is very small and that's why it's of interest," said Burton, a UI aerospace engineering professor and director of the Center for Space Technology and Research.
Weight is a big factor in lofting stuff from the planet into orbit. The less spent on fuel, the more that can be dedicated to valuable payload.
The UI rocket can't do anything about the heavy fuel demand to get off the Earth and into orbit. But it could reduce the amount of fuel needed, say, to move a supply ship to a moon base once the craft is in orbit.
Burton and Rob Thomas, a UI doctoral student in aerospace engineering, won a NASA grant to design, build and test the so-called gallium electromagnetic thruster, which will convert 50,000 watts of electric power into rocket thrust.
Gallium is a soft silvery metal that literally melts in your hand. It liquifies at a little more than room temperature and looks something like mercury, but without mercury's toxicity.
The substance, a trace component in coal among other places, is used in the computer chip industry to make transistors and other electronic devices and in making high-quality mirrors. Burton and Thomas are putting it to a different use, however, as rocket fuel.
Basically, the electric current created in their system generates a magnetic field that pushes the gallium out a rocket nozzle at high speed, about 25 miles a second or 10 times faster than a chemical rocket's exhaust moves and five times faster than the space shuttle's speed in orbit.
The rest is basic physics, the old rule stating that for every reaction there's an equal and opposite reaction. The gallium goes one way, the rocket and its payload the other.
Gallium isn't inexpensive, about $1,000 a pound, but it provides a high-power thrust with little fuel consumption and wouldn't be especially costly in the context of a billion-dollar space vehicle, Burton said.
He said the electric power for the system can come from either solar cells or a small nuclear reactor.
Various types of electric thrusters aren't uncommon in space now. Besides being fuel efficient and capable of providing a powerful thrust, as in the case of the UI system, some variations also can be used to make precision adjustments, within a millimeter, to a spacecraft's position.
That's more than enough to adjust communications satellites and they've also been used to line up space probes to rendezvous with asteroids and comets, among other things.
Burton and Thomas are supposed to test a small laboratory version of their thruster by this fall, which they do in a heavily instrumented vacuum chamber at the UI, tracking how it performs on a variety of levels.
If the first test is successful, Burton said the UI researchers hope to be able to obtain funding to build a larger version.
Besides NASA's Marshall Space Flight Center in Alabama, which focuses on space propulsion and transportation technologies, a local company, CU Aerospace, and the Air Force are participating in the project.