NASA's NEXT ion thruster runs five and a half years nonstop to set new record


June 26, 2013

The NEXT ion thruster has run for 48,000 hours (Image: NASA Christopher J. Lynch (Photo: Wyle Information Systems, LLC))

The NEXT ion thruster has run for 48,000 hours (Image: NASA Christopher J. Lynch (Photo: Wyle Information Systems, LLC))

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On Monday, NASA announced that its advanced ion propulsion engine operated for 48,000 hours, or five and a half years – and that’s without stops for fuel or coffee. Developed under NASA's Evolutionary Xenon Thruster (NEXT) project, the engine now holds the record for the longest test duration of any type of space propulsion system.

NEXT is a solar electric propulsion system where electricity from the spacecraft’s solar panels is used to power a a 7-kW class ion thruster. In this, particles of xenon gas are electrically charged and then accelerated to speeds up to 90,000 mph (145,000 km/h). Such thrusters have already been used on spacecraft, such as NASA’s Dawn probe, and engineers are very interested in them because of their much higher performance compared to conventional chemical rocket engines.

The test was carried out in a vacuum chamber at NASA’s Glenn Research Center in Cleveland, Ohio, where the NEXT thruster continually fired day and night. In December, it had already passed 43,000 hours of operation and when it passed 48,00 hours it had consumed 1,918 lb (870 kg) of xenon propellant and generated a total impulse that would take over 22,000 lb (10,000 kg) of conventional rocket propellant for comparable applications.

NASA hopes to use NEXT or some version of it in a wide range of deep space missions. The thrust made by an ion engine is tiny compared to a chemical rocket, but its very high efficiency combined with its ability to fire for years on end means that it can build up astonishing speeds over time. As for the test model, it is on its way to a well-deserved retirement as it is switched off.

"The NEXT thruster operated for more than 48,000 hours," says Michael J. Patterson, principal investigator for NEXT at Glenn. "We will voluntarily terminate this test at the end of this month, with the thruster fully operational. Life and performance have exceeded the requirements for any anticipated science mission."

Source: NASA

About the Author
David Szondy David Szondy is a freelance writer based in Monroe, Washington. An award-winning playwright, he has contributed to Charged and iQ magazine and is the author of the website Tales of Future Past. All articles by David Szondy

@Bill Cumming This doesn't exactly answer your question, but I calculate that a 5,000lb spacecraft putting out 1lb of thrust would be going about around 1.3 million mph after 10 years.


Nah, LEO would be a good use for it. But mining an asteroid might be better. setting up a space station in the asteroids to mine several of them might even be better. i wouldn't want that duty.


Excellent research, now donate it to the San Diego Air and Space Museum for all to enjoy.

Mark A

I think they should keep it running until it dies. It would take a very long time for a few little tugs to clean up LEO.


Just wondering how fast a probe with 5,000lb of xenon fuel it would be moving after 10 years under thrust?

Bill Cumming

I want one to replace the ICE in my Prius.


I agree with Mark A, it should go to a musuem where others can see how cool it is and how it is the first step into the future.


To check the force that would propel your Prius with this ion thruster, get a standard issue 100 gram chocolate bar (go for the dark 85% cocoa!) and eat three-quarters.

Then, take the rest and put it on your flat hand. The force you need to hold that piece of chocolate is about equal to the thrust from this engine.

But no worries - remember people pointing out how much stronger horses are when they saw the first motor cars? Things take time...


Interesting article. I was wondering what the velocity and/or temperature of the exhaust is? Is there any chance at all that the ion thruster technology will ever be able to accelerate protons to a high enough energy so the p+Boron fusion reaction can be made to happen? For the uninformed this is a clean nuclear reaction producing no nasty radioactive byproducts.


I don't think it's ever going to go faster than the exhaust of 90,000 mph.

Paul Bedichek

The initial thrust can be provided by conventional rockets and this will be active too maintaining and accelerating. Plus gravitational slings can be used to accelerate.

Sadaf Dawar

Old tech never dies, its just given another name. LOL

S Michael

How long till in spacecraft use IE manned or unmanned??

Stephen Russell

@ Paul Bedichek It possibly could go faster than the exhaust. Sailboats can travel faster than the wind speed.

Jerry Odom

re; Paul Bedichek

A little experiment; get on a wheeled cart and throw a brick as hard as you can and see how far you roll then take your brick and cart onto a high speed train when the train is traveling at speed get on the cart and throw the brick at the rear of the train as hard as you can and see how far you roll towards the front of the train.


Cool, but it still doesn't make the iconic potato potato sound of my 1991 Harley.

Ron Evans

@Paul Bedichek @Bill Cumming Mass of spacecraft 10,000 kg (assume capsule mass 5000kg) Thrust of Engine 0.236 N (F=m*a) Acceleration 0.0000236 m/s^2

Time (s) 31,556,900 s (a=v/t) Velocity (m/s) 744.74284 m/s % Light 0.000248% c Mach 2.18855341 (d=r*t) Distance 23,501,775,327.60 m Lightyears 0.000002484


Just incase Paul is wondering "What was I thinking, I've heard that before?". Vacuum is the difference. If you exhaust slower than your speed in atmosphere you'll just end up causing drag where exhaust is exiting. There is some drag in space so yep, it'll eventually hit a speed limit :) Well that's as I understood it when I build rockets as a kiddie :P

Craig Jennings

BeWalt- NASA's existing Dawn spacecraft puts out only one FIFTIETH of a pound, per the NASA website. Specifically it says it puts out 90mN, which is 90 milli-newtons, which converts to 0.02 lb, 0.3 ounces or 9 grams. I didn't see any mention of what the NEXT was running at, but the Glenn research division of NASA website says that Modern ion thrusters can deliver up to 0.5 Newtons (0.1 pounds) of thrust, which is equivalent to the force you would feel by holding nine U.S. quarters in your hand. I'm always suspicious of a large gap between what the actually have in service, in space, and what they say they have ready to go. Also doesn't say what efficiency (specific impulse) the thing would run at at 0.5 newtons. For deep space, you don't want to be burning all your fuel up here alone,

Norm Frey

since you have this record setting ability to propel for this length of time, now its time to slow down, turn end over end and restart for an orbit matching burn. I feel this additional testing should at least contain several short corrective bursts of sufficient duration to test for any fluctuations vibrations, anomalies of any sort. what say you guys?

Bill Kratzer
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