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NASA's NEXT ion thruster clocks up continuous operation world record

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December 27, 2012

NASA's NEXT engine (Photo: NASA)

NASA's NEXT engine (Photo: NASA)

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NASA's Evolutionary Xenon Thruster (NEXT) ion engine has set a new world record by clocking up 43,000 hours of continuous operation at NASA’s Glenn Research Center’s Electric Propulsion Laboratory. The seven-kilowatt thruster is intended to propel future NASA deep space probes on missions where chemical rockets aren't a practical option.

Ion propulsion has come a long way from the 1960s when it was an engineering curiosity with a cool Star Trek name. Instead of burning fuel, an ion thruster gets its electrical power from solar panels or a nuclear power source. It uses this electricity to ionize molecules (in NEXT’s case, xenon) and then a cathode to accelerate them electrostatically. As the molecules shoot out the back of the engine, they create thrust.

Diagram showing how an ion engine works (Image: NASA)

That sounds simple, but the amount of thrust is tiny – about the equivalent of the weight of a coin resting on a table. Where the ion thruster has it over chemical rockets is, firstly, in terms of efficiency – ion thrusters are 10 to 12 times as fuel efficient as chemical rockets. Secondly, an ion thruster can run for a much longer period of time. Where chemical rockets burn for minutes, ion thrusters can burn for thousands of hours, which allows that tiny amount of thrust to build up into speeds needed for deep space missions.

The NEXT ion thruster is one of NASA’s latest generation of engines. With a power output of seven kilowatts, it’s over twice as powerful as the ones used aboard the unmanned Dawn space probe. Yet it is simpler in design, lighter and more efficient, and is also designed for very high endurance.

Its current record of 43,000 hours is the equivalent of nearly five years of continuous operation while consuming only 770 kg (1697.5 lbs) of xenon propellant. The NEXT engine would provide 30 million-newton-seconds of total impulse to a spacecraft. What this means in simple terms is that the NEXT engine can make a spacecraft go (eventually) very far and very fast.

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
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22 Comments

IMO; that sounds really cool. I think it is the future for propulsion.

BigWarpGuy
28th December, 2012 @ 05:26 am PST

Too bad it needs Xenon gas, that makes the engine unsustainable, Any other material like space rock would be better, though hard to collect in empty space, because of the speed difference.

jochair
28th December, 2012 @ 06:26 am PST

7kw is about 7000 / 640 watts per horsepower = 10.9 horsepower

that doesn't sound anything at all like the amount of power needed to

support a coin on a table.

Now, what kind of nuclear power will they use to run it? How much does it mass? What is it's fuel mass loss? Couldn't they use a denser, solid material instead of xenon and heat it to the useful temperature and save on storage mass/volume? Can the process be scaled up to 1000 times current power? Can any form of mass be used as long as it is heated to gas/vapor temperature? If so, then you could use solar panels when near a sun for power and then use their mass as fuel when away from the sun. Thus reducing vehicle mass at the same time.

notarichman
28th December, 2012 @ 08:35 am PST

Encouraging research and development projects continuously produce results, such as the Xenon ion thruster for future space exploration missions. Evidence of remarkable achievements continue in most all the disciplines, except in the realm of humanity's domain and condition

. Billions are spent in pursuit of knowledge relevant to areas of science which currently have little to do with the human condition overall. In effect, - hanging curtains before the house is built. Agreed, - it isn't all negative, since much has been discovered which has produced beneficial knowledge applicable to the development of new discoveries in biology and medical science. However, nothing of tangibility has so far been discovered to transform human nature which will allow it to overcome the destructive influences of 'greed' and the lust to control and dominate other members of our species to a status-dominated sub-cultural state.

Robert Arthur Gillis
28th December, 2012 @ 09:10 am PST

"What this means in simple terms is that the NEXT engine can make a spacecraft go (eventually) very far and very fast."

How far? How fast?

Tholzel
28th December, 2012 @ 09:25 am PST

I was under the impression that ions could be gathered in space much as rocket engines gather more combustible air to accelerate as the ion propulsion systems gather speed. Aren't ions available everywhere in space? And the only thing necessary is to gather and channel them for thrust? Or am I just such a neophyte that I believe in Star Trek too much?

Jess Atwell
28th December, 2012 @ 09:37 am PST

@ notarichman

This engine is for space travel. Not take-offs or landings. And in space, where there's pretty much nothing to slow down the spacecraft, any amount of force will do. This engine is a constant, reliable and durable source of thrust, which is exactly what NASA wanted for space travel. This engine is gonna get people to Mars one day.

Nitrozzy Seven
28th December, 2012 @ 10:04 am PST

the only problem i have with this type of engine is it leaves no room for error in navigation. what about the plasma engine more power required but far more thrust.

frogola
28th December, 2012 @ 12:42 pm PST

Better yet this engine or one like it will get us to Mars in weeks instead of months.

Michael Gene
28th December, 2012 @ 12:43 pm PST

@Nitrozzy: error in navigation? I don't think that's an issue. Traveling through space isn't like missing the exit ramp on the freeway, it's pretty straightforward.

Mike Maxwell
28th December, 2012 @ 02:16 pm PST

One would have to attain a fairly high velocity to make interstellar travel worthwhile right? Say, 0.5 c perhaps? Well, besides all the obvious engineering challenges (none really insurmountable), what about collision avoidance? Seems a pitty to take all that money away from feeding the poor, honoring the elderly, providing quality education for the masses, ongoing medical advancements and the like, just to be obliterated by a rougue asteroid somewhere....

Remember, in Space no one can hear you say "awe s#!t!..."

Burnerjack
28th December, 2012 @ 03:53 pm PST

This tech might be useful to push NEOs into the sun or out to Jupiter. Land it when close and the NEO could be gone before it would have come around again. Slowburn but long duration adds up.

Intellcity
28th December, 2012 @ 04:54 pm PST

Very little understanding of Newton in the preceding posts. Assuming constant thrust after reaching escape velocity on another rocket, after separation this ion engine of 7 kW output will produce an acceleration inversely proportional to the decreasing total mass. Distance from the sun, damage to solar receivers, murphy's law, etc are generally negative influences.

Marvin Keith
28th December, 2012 @ 06:55 pm PST

This thruster will be a handy tool in NASA's arsenal but don't get too excited. Five years is barely enough endurance for interplanetary travel, and not even a blade of grass in the ball park for interstellar journeys.

nutcase
29th December, 2012 @ 03:45 am PST

30,000,000 newton seconds = 20159069.2542 lb/ft*s

(http://www.unitconversion.org/viscosity-dynamic/newton-seconds-per-square-meter-to-pounds-per-foot-per-second-conversion.html)

If the space craft weight was 10 tons is would be 20,000 lbs

20159069/20000 = 1007 ft /sec

1007 *3600 = 3628632 ft/Hour

3628632/5280 = 687 Miles per hour

So at the end of 5 years our 10 ton space craft is going 687 mile per hour faster than what it started out at.

How this compares to what we have now for the long distance space probes I do not know but I think it will not be taking us to Mars in weeks or months.

The distance to mars varies because of the respective orbits but it was down to 35,000,000 miles in 2008

(http://www.universetoday.com/14824/distance-from-earth-to-mars/)

at 700 miles per hour it would take 50,000 hours (35,000,000/700 ) to get there which is about 2083 days (50,000/24 ) or about 5 years

Actually it would take a lot longer because it takes 5 years to reach that velocity. Of course there is a lot more involved , the starting velocity , time for accell , time to decel , changes in mass as fuel is consumed etc. but my point is that we won't be strapping an Ion engine onto a space capsule and commuting to mars any time soon.

Captain Danger
29th December, 2012 @ 12:52 pm PST

Using the vague 'force of coin on table' starting point...

Mass of coin (say US quarter) is 5.67g = 0.00567kg

Force on table at sea-level on Earth = 9.81 x 0.00567 = 0.0556N

Total guess at average mass of spacecraft say 2000kg including fuel and assuming the mass doesn't change (which, of course, it will)...

F = ma ; a = 0.0556/2000 = 2.78e-5 m/s/s

Assuming zero initial velocity and no other forces acting on the spacecraft, distance traveled in one year (3.15e7 seconds) will be

s = ut + 0.5at*t (u = 0) ; distance (s) = 1.38e10 meters = 13.8million km

This is about 1/10 of the distance to the sun (0.092 astronomical units)

After one year the craft will have a velocity of v = u + at (u = 0) = 876m/s

After 5 years the numbers are distance : 346million kms (half way to Jupiter) and velocity 4390m/s

-dphiBbydt
29th December, 2012 @ 03:42 pm PST

@ Captain Danger; -dphiBbydt

Assuming that is we do not give the spacecraft a good shove first :)

L1ma
30th December, 2012 @ 08:05 am PST

re; -dphiBbydt

Done with less than a ton of reaction mass.

Slowburn
30th December, 2012 @ 04:38 pm PST

I'm very excited about this deep space project. I work at the reactor facility that is working with NASA to develop the fuel source for these probes. It's a great project with a lot of challenges, but is really interesting. I have a penchant for space and space exploration and love working on this project.

Matt Clagett
30th December, 2012 @ 06:56 pm PST

?? Back when DARPA was experimenting with laser weapons like laser rifles, an optical laser phenomena called 'Repercussion' would occur when a soldier aimed a laser rifle at a mirror or reflective surface, and the laser would 'Repercussion' throughout its length to knock the rifle out of his hands. Eventually, NASA heard about this, and devised repercussion laser setup that could propel tiny payloads about by shooting an optical laser beam into a mirrored part of the tiny capsule, with the hopes that someday we could make massive laser propulsion systems that could project-propel much larger payloads clear into orbit using ground powered lasers. The thing is, what if they could combine this optical laser 'Repercussion' with this ionic drive? Perhaps they could create an optical laser of such a specific frequency, that it could propel ionized gas molecules, so that this 'Repercussion' effect could make an ionic drive with greater fuel efficiency or greater speed as well?

Techrex
19th January, 2013 @ 09:19 pm PST

Techrex; Lasers have almost ZERO kinetic energy . Its as if You have no idea what a laser even is.

Brian Mcc
6th March, 2013 @ 07:40 pm PST

What about this article?

http://www.gizmag.com/ad-astra-ion-engine-mars-39-days/12342/

Seems to be a lot faster

Thor Russell
6th March, 2013 @ 08:25 pm PST
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