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ESA Moves Forward on New Electric Engine
museumpeace writes to tell us the ESA is reporting that they have confirmed the principle behind a new space thruster. Plasma Double Layers, first discovered by Australian researchers Christine Charles and Rod Boswell, may help to develop a new electric engine that gives more thrust than traditional engines while still maintaining efficiency. From the article: "In essence, a plasma double layer is the electrostatic equivalent of a waterfall. Just as water molecules pick up energy as they fall between the two different heights, so electrically charged particles pick up energy as they travel through the layers of different electrical properties."
My work here is dung.
No I'm not. I really want to know how big of an impact people think this new design will have.
My work here is dung.
Because these are very low thrust engines, they can't hold a candle to gravitational forces. Where they shine in interplanetary and stationkeeping (orbit and orientation) applications.
-everphilski-
Would the article submitter PLEASE not call ion engines "traditional thrusters"?
Now back to thrusting my girlfriend traditionally.
--- Eat my sig.
I can't wait to put one of these bad-boys in my Civic!
In essence, a plasma double layer is the electrostatic equivalent of a waterfall. Just as water molecules pick up energy as they fall between the two different heights...
Water molecules do not pick up energy as they fall. There potential energy is simply converted into kinetic energy. However, they had the energy all along in the form of potential energy.
Energy source for the SSME is combustion (Hydrogen and Oxygen)
4 3.html ... even 10*5 times more thrust is only 5 newtons (read: not much). Scale it up to a SSME sized engine and your talking maybe 25-50 newtons. SSME thrust is measured in MILLIONS of newtons.
Energy source for this engine is electricity, or rather an energy potential... solar cells, nuclear power plant, etc.
Two different concepts. Two different ballparks. While the article states that this method will deliver "many times more thrust" than ESA's "SMART-1" thruster (70 mN, thats mili-newtons) http://www.aoe.vt.edu/~cdhall/Space/archives/0003
So basically, different tech that won't scale to drive a vehicle out of a gravity well. But it is useful for orbital/stationkeeping/interplanetary maneuvers if you have the time.
-everphilski-
There not really "Electric Engine"s either are they?
Calling them Electric Engines would mean calling pretty much every engine around an electric engine.
Plasma or Ion engine's would be more descriptive in my opinion.
flowerp: I am now thrusting you traditionally.
SexyAnGeL_69: Talk geeky to me.
flowerp: I just read on Slashdot about a new electric engine.
SexyAnGeL_69: Oh wow! I'm....oh yes! Traditionally thrust me you bad boy!
Read about this on the BBC article, with diagram This morning... Sounds like it's greatest use will be in deep space missions. It still hold potential for other use if we can find a more efficient way to use it.
-Khyras
The real question is: How do these thrusters stack up to MPDTs (Magnetoplasmadynamic thrusters)? The article is light on technical details like Isp, engine life, potential design issues, fuels, etc. MPDT is a great upcoming technology. But if this new tech can best it by having a shorter development track and equivalent performance, then let's leapfrog the MPDT technology altogether! :-)
Javascript + Nintendo DSi = DSiCade
I would hesitate to call this a "very low thrust" engine, since 100kw is somewhere around 140 horsepower. It may not be enough to escape earth's gravity (if not, maybe the mars or the moon?), but I wouldn't discount the possibility immediately without more information (like what do these thrusters weigh, and how much propellant do they need to carry).
The hardest part would be providing a 100kw power source, but this is the same problem as supplying power to the space elevator climbers, and it might be solvable with wireless power transmission (big lasers and solar panels).
...can it go to Ludicrus Speed?
The ion engines rely on the same principle of accelerating propellant through its electromagnetic properties. Plasma is an ionic gas, and propellant is gas too. The only difference I could imagine is that the method of ionization itself produces thrust. Is this indeed the source of higher energy efficiency? The description of two levels sounds like two varying magnetic fields which cause magnetically charged particles (plasma) to accelerate, and the divergence sounds like magnetism applied to aerodynamics. Perhaps this is another source of higher efficiency. If so, this really is groundbreaking.
How about through a semi-conductor so you can adjust burn rate with a slight bias adjustment? =)
that there's a 2N3055 Mach V Rev 1.2, mebbe they have an equivilent replacement at rocket shack
A feeling of having made the same mistake before: Deja Foobar
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"Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife
You must be new here.
It probably already is. :-/
Nothing to see here, move along now.
You are in a twisty maze of processor lines, all alike.
There is a lot of hype here.
Plasma needs to come from somewhere. Even if you have some renewable energy source like a solar panel, eventually you will run out of ions to exhaust.
I think that's the point of the design. The ions can be accelerated without the need for being attracted by cathode plates or wire mesh at the back, as is done now.
The principle was popular in particle accelerators for a while - I worked at Daresbury some time back, which was a 20 MeV tandem accelerator. It's cheap and easy. A variant, only with reversed electrical fields, was used in old-fashioned thermionic valves. In that configuration, they were termed deflection grids. CRTs use the same technology to steer electrons towards the correct place on the screen.
Not sure why anyone would need to prove the idea would work in space, since we already use the technology in vaccuum and we already know tandem accelerators can produce greater acceleration than a single grid.
I would be much more interested in knowing if it were practical to ionize oxygen then use this technique to improve the oxygen/nitrogen ratio in the engine. If you could, it would improve engine efficiency and may help in reducing the complexity of the engine electronics and mechanics.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
(Astronomers are, as a rule, mystified by plasma-dynamic events, leading them to talk about "hot gases", "stellar plumes", "galactic jets", "magnetars", "dark matter", "dark energy", and worse. For most, their only exposure to anything like plasma in school was an unphysical mathematical construct called MHD, so they are worse off than if they'd skipped class. (Hawking is often quoted, with no trace of irony, saying "the greatest enemy of knowledge is not ignorance, it is the illusion of knowledge.") For those of us even a little more familiar with real plasma effects, astronomical press releases are no end of hilarity.)
Plasma double layers aren't mysterious. They develop naturally as the diffuse particles containing ions tend toward equilibrium. Variation in composition, ionicity, and density in a diffuse plasma gather at boundary layers between regions, making the space between the boundaries much more uniform, and concentrating mass, electric fields, and current flow. Highly-stressed double layers tend to explode; on the sun they call it a "coronal mass ejection". On another star it may be called lots of things.
In one of those plasma ball toys, you can see double-layer tubes connecting the electrode in the center with the transparent ball. You see them because the current density is high enough to put the plasma it runs through in "glow-discharge" mode, exactly as in a neon sign or St. Elmo's Fire. The other two modes are "invisible" and "arcing". The former is common throughout the universe (and detectable only indirectly, as you might imagine) such as between the earth and the sun, between star systems, and even between galaxies. The latter is what you see in a lightning bolt, on the surface of the sun, or in one of those spotlights they used to use at movie premieres. Astronomical glow-discharge events (with the exception of earth's polar aurorae) are usually confused with "shock waves".
The most beautiful astronomical glow-discharging double-layer structure I know of is M2-9 in Ophiucus. "In this image, neutral oxygen is shown in red, once-ionized nitrogen in green, and twice-ionized oxygen in blue."
to the Variable specific impulse magnetoplasma rocket?
What I'm thinking about is that this "new" Ion engine has a higher thrust and/or a higher specific impusle than a standard Ion engine (like the one on Deep Space 1.) But how does it actually rate against the VASIMR style engine and does it have the flexibility of it? (That is, can it adjust it's SI/Thrust depending on the situation - orbital maneauvering vs. cruising.)
Bill
It's my Sig and you can't have it. Mine! All Mine!
Cassini has to fire its main engines once every 400 days in order to flush corrosion from the cat beds that might clog the lines otherwise... This has never been much of a problem to do as small maneuvers can be planned without messing up the interplanetary trajectory.
Actually for interplanetary missions chemical rockets are far less risky than low thrust systems. This is because chemical rockets instantly change you from one safe trajectory to another.. low thrust engines make this change over several days and as a reult there are often periods where if the engine fails the spacecraft would be left on an unstable orbit that is likely to crash into something or be thrown into an escape trajectory. JIMO and Dawn both had major problems trying to design trajectories that always left enough time to recover from possible engine failures without crashing.
It all comes down to control authority... bigger thrust gives you more control authority and you can much more easily recover from unexpected trajectory perturbations.
There are 10 types of people in this world, those who can count in binary and those who can't.
If you don't know much about the ion engine used in Deep Space I, look here before posting.
The article mentions that this new thruster design's "fuel efficiency" is comparable to the ion engine. This means that it has to propel about the same amount of ionized gas away to get the same amount of thrust (presumably at a similar velocity). However, I didn't see anything about "energy efficiency". Does it require a lot more electricity to get the same amount of thrust? For a space probe, 100kV is a LOT. The Deep Space I probe had solar panels that generated 2.5kV, and it didn't even have enough electricity to run its ion thruster simultaneously with most of its other systems. Sure it would be nice to have the option to accelerate more quickly, but will there be enough electricity available to take advantage of it for long periods of time?
Just as water molecules pick up energy as they fall between the two different heights,
They are not picking up anything, they are just transforming potential into kinetic energy.
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