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The Future Of Thrust Technology Is Ion Propulsion
Thu, 09/26/2013 - 2:05pm
by Chris Fox, Associate Editor, PD&D
We are all painfully familiar with the cost of filling the tank – even with a hybrid, visiting the gas pump isn't fun. Similarly, NASA is familiar with the high cost of launching vehicles from Earth, as it takes about $10,000 per pound to launch things into space.
But, what about propulsion once the craft is up there? Satellites, spacecraft, and deep-space probes require thrusters to keep them in place or push them wherever they need to go – not an easy task when space, payload, and cost are incredibly finite.
NASA’s answer to these issues has been the development of ion propulsion engine technology, and projects like NASA's Evolutionary Xenon Thruster (NEXT) Project at the Glenn Research Center. The NEXT Thruster was recently sanctioned to be shut down after running for more than 48,000 hours, or somewhere around five and half years, as a test of the system.
The test was performed in a high-vacuum chamber where the engine used about 870 kg of xenon propellant.
The NEXT Thruster uses Xenon propellant, which is used for most electric propulsion systems. Xenon is an advantageous propellant because it’s inert, so it is non-reactive and non-contaminating to ground test facilities or spacecraft surfaces, and it has a high Atomic mass unit (AMU), which results in a high thrust-to-power ratio.
Also, Xenon propellant is highly condensable (about twice the density of water at high pressure), making it ideal when space is limited. Using Xenon propellant, this thruster technology could readily change a spacecraft velocity over the duration of the thruster lifetime by greater than 10 km/second.
The amount of impulse produced would have consumed more than 10,000 kg of conventional rocket propellant in similar applications. Ion propulsion is nothing new to NASA, but with NEXT, they are hoping to take science and observation to further and more challenging destinations than ever before
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