Spacecraft the size of a loaf of bread may study deep space

University of Michigan team building superheated plasma-powered engine to power tiny CubeSat craft into interplanetary space

Engineers at the University of Michigan are looking to use spacecraft the size of a loaf of bread to study interplanetary space faster and cheaper.

Scientists at the school are building a plasma thruster that could push a small satellite-bearing spacecraft into deep space. To meet the goal, the thruster needs to be small enough to fit in a 10-centimeter space.

While such small thrusters do exist today, they lack enough sustained power to power a spacecraft through very long distances.

"If we wanted to try a mission like the one we're proposing with current technology, we wouldn't even make it out of Earth's orbit," said Benjamin Longmier, a University of Michigan assistant professor in the Aerospace Engineering Department. "We have some little thrusters called gas jets that will push us a little bit, but we want to be able to push a spacecraft millions of miles from Earth and go truly interplanetary."

The plans call for the new thruster to use superheated plasma that would be pushed through a magnetic field to propel the small spacecraft, called a CubeSat.

James Cutler, also an assistant professor in the Aerospace Engineering Department, has helped build and launch three CubeSats into orbit since 2008.

In the latest project, Cutler and Longmier are teaming up to develop ways to push the tiny spacecraft much further out into space.

"The problem with the spacecraft we currently build is they don't move," Cutler said in a statement. "There are some very interesting places that we'd like to go. So Ben's come along and hopefully we can combine these two efforts and go to some very interesting places."

Not having the needed very small, powerful propulsion system is limiting the potential destinations for the CubeSat spacecraft, he added.

The project also calls for building a stronger, more resilient spacecraft -- today's CubeSats could not survive the harsh environment of interplanetary space.

In late May, NASA announced that data sent back from the Mars rover Curiosity during its trip to the Red Planet last year showed the high levels of radiation that bombarded the spacecraft on its journey. Researchers are using the data to design protective systems to shield future spacecraft, and humans, from radiation exposure on deep-space expeditions.

Engineers are going to forego typical propellants, such as xenon or krypton, which are both colorless, odorless, tasteless noble gases in favor of liquid iodine, more commonly known as distilled water, for the new thruster.

According to the university, the thruster would vaporize the distilled water, superheating it into a plasma state. The plasma will then be pushed between magnetic fields, that create a virtual nozzle, propelling the spacecraft in the opposite direction.

Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin, or subscribe to Sharon's RSS feed . Her email address is

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