New Engine Raises Possibility of Cheap Travel To the Moon

shreshtha writes with this intriguing bit from The Daily Mail: "A tiny satellite thruster which can journey to the Moon on just a tenth of a litre of fuel could usher in a new low-cost space age, its creators hope. The mini-motor weights just a few hundred grams and runs on an ionic chemical compound, using electricity to expel ions and generate thrust. The tiny motor isn't built to blast satellites into orbit — instead, it's to help spacecraft manouevre once they're in space, which previously required bulky, expensive engines."

Comments

Sweet!

[Lije Baley]

To whom shall I write the check as I securely invest my life savings?

Re:Sweet!

[Anonymous Coward]

No joke, especially considering this is from the Daily Mail. I mean come on, why would they even think anyone would get real news from such a place.

Re:Sweet!

[tommasorepetti]

https://en.wikipedia.org/wiki/Deep_Space_1 This is not exactly new... at all. NASA's ion engines have been in service for several years now. Also a tenth liter of fuel is also willfully misleading: the engines expell a liter of propellant but that is not fuel. It is just the expelled material whose momentum generates the forward thrust.

Re:Sweet!

[EdZ]

Well, it is the Daily Fail. It may have taken them over a century to report on the concept of the Ion Thruster, but at least a few of the facts in their story are actually correct (which is probably a new record for them).

Re:Sweet!

[crutchy]

my car doesn't use fuel either... just material that when ignited in a mixture with oxygen generates an explosion inside a chamber with a piston that imposes a moment in a crankshaft and induces a reaction from the earth against the tire surfaces in such a way as to get me where i need to go with a bit of interaction via an orientation correction device inside the cabin. apparently there are 6 of these miraculous so called "cylinders" in my transportation machine! modern technology is just amazing isn't it?

Re:Sweet!

[wagnerrp]

You misunderstand. Your car is fueled by gasoline, which drives the pistons. This "new engine" is fueled by a nuclear reactor, or solar, or whatever, and the tenth liter of "fuel" is just inert reaction mass. There is no energy to be extracted from it, it's merely something to push off of.

Re:Sweet!

[tommasorepetti]

The difference is this: a rocket engine not only uses the oxygen/hyrdrogen mixture as the propellant (the steam that is being expelled from the rear) but also as a "fuel" i.e. that from which the whole process derives its energy. The ion engine is using an imposed electric field gradient to accelerate the charge particles (ions) of its propellant out into the vacuum of space and to move the probe foward. The energy for this is coming from a combination of solar panels and a battery. One other weird thing about these engines: the reason it takes six months is because it takes forever for these things to reach speed. 0 to 60 is something like a few days. If you leave them on for years (liike Deep Space 1), it will reach many tens of thousands of mph because these little particles have been contributing their momentum so consistently for such a long time. If Picard were at the helm of an ion-engine-powered vehicle there would be an awkward decade-long pause after he ordered the Enterprise to go to warp factor two...

Speed

[Sarten-X]

I was under the impression that fuel to get to the moon isn't a major issue, if you can launch a few years before you need to be there. There's (almost) no friction to stop you...

Re:Speed

[ColdWetDog]

Anorexic hamsters, possibly. Even Kate Moss weighed more than a kilogram.

(You must be American and unfamiliar with SI units.)

Re:Speed

[ShanghaiBill]

So basically, Anorexics make perfect astronauts.

Or double amputees. Arms are useful in space. Legs are just excess mass that take up space and get in way.

From Where?

[Colonel Korn]

Seriously, I can travel to the Moon with no fuel if I start in the right position with the right momentum. TFA doesn't tell us much unless the secrets are hidden in the video I'm blocking on the bottom of the page.

Re:From Where?

[Colonel Korn]

Seriously, I can travel to the Moon with no fuel if I start in the right position with the right momentum. TFA doesn't tell us much unless the secrets are hidden in the video I'm blocking on the bottom of the page.

Sorry to self-reply, but:

Can we stop having summaries posted where the only link goes to the Daily Mail? Every human should be disgusted that our species can produce something as wretched and pathetic as that hive of stubborn ignorance.

Re:From Where?

[ColdWetDog]

Maybe we can try 'right position and right momentum' with Timothy'. A good swift kick in the kiester would do him some good....

Re:From Where?

[hrshea]

As the lead author of the work, I'm happy to give you some more direct links EPFL press release: http://actu.epfl.ch/news/getting-to-the-moon-on-drops-of-fuel/ MicroThrust consortium: http://www.microthrust.eu/ EPFL research on micro propulsion: http://lmts.epfl.ch/microthrust

The propulsion system emits ions at high speed (40 km/s) and is thus very efficient at converting propellant mass to satellite momentum. Thrust is low, but given time, ver lge orbit chanegs are possible. for example, in order to reach lunar orbit from low-Earth orbit, a 3-kg nanosatellite with our motor would travel for about 2 years and consume about 500 grams of fuel" - Herb Shea

Re:From Where?

[Anonymous Coward]

Wow. Just... wow. At first I thought the reason this was over-hyped was because it was in the Daily Fail. But no. You actually have it on your own press release.

You, sir, are a charlatan. Perhaps you can get to the moon on a few "drops" (nice non-defined quantity there) of fuel, but you have to start in Earth orbit - ie in terms of energy 99% OF THE WAY THERE.

If you had any decency at all, you would at least insist that your own headlines be something along the lines of "From Earth's Orbit to the Moon on 500g of fuel" or some such, and make clear in the first sentence that you're talking about 3Kg satellites, not entire space shuttles, but instead you imply that I can fill up a half-liter of fuel in my ship here, bid farewell to Cape Canaveral, and be on the moon shortly.

This has really got to stop. Honest claims about genuine research are great, but this kind of overblown bullshit hurts all of science. When people find out that in fact you've just moved the goalposts so far that the goal you've achieved isn't anywhere near what you're advertising, they lose faith in all of us.

Re:From Where?

[nojayuk]

Sound like a smaller version of SMART-1 launched in 2004 which used an ion thruster consuming 80kg of xenon propellant to move a 300kg satellite from orbit around Earth to a Lunar orbit about 15 months later. The neat thing you're suggesting is doing it with a microsatellite although whether it could carry out any sort of useful function once it was in Lunar orbit is debatable; just having enough radio transmission capability to return scientific data to Earth on such a small satellite would be a major stumbling block.

Re:From Where?

[wagnerrp]

Despite the futility of responding directly to an AC, there are inherent limits to an electrostatic (ION) drive. You increase your exhaust velocity by increasing your voltage, however if you increase your voltage too far, you arc between your electrodes and waste all your power. The only way to increase velocity is to build larger, increasing your gap, to allow for higher voltage. This actually achieves a higher exhaust velocity than it should by "cheating" in a pretty ingenious fashion. Rather than using one electrode to ionize the propellant, they're starting with an electrolyte, and using alternating current to prevent the build up of DC bias between the grid and the solution, effectively halving their operating voltage for the same performance.

Wow

[kamapuaa]

Who would have guessed this got posted by Timothy!

Someone's reinvented the ion engine

[Scareduck]

If this were news for nerds, maybe someone would have researched this before posting?

Forget it, Jake. It's Slashdot.

Re:Someone's reinvented the ion engine

[wisnoskij]

I do not think that the news is that they reinvented it, and seriously everyone on /. knows of the about ion-engines so there is little point in even mentioning it. But that here is a practical use of that engine that works better then anything else we are currently using.

Re:Someone's reinvented the ion engine

[EdZ]

Except we did use it. To go to the moon. Over a decade ago.

Misleading

[mmmmbeer]

The new thruster has nothing to do with getting to the moon or even getting into space. It's a way for a small satellite to maneuver once it is in orbit. It could possibly be used for getting into lunar orbit from low earth orbit, but its intended purpose right now is to help clean up debris.

Read this site first.

[khasim]

http://www.projectrho.com/rocket/enginelist.php#id--Ion

It's a great site which details (with lots of math) the various problems with space travel.

The expensive part

[gmuslera]

is launching to space from earth/moon surface. Traveling once there, and landing (at least in earth) could be relatively inexpensive. But once the space elevator, space fountain or other approaches are built and gives us relatively cheap ways to reach space, this kind of approachs could make a difference.

Re:How is this new?

[queazocotal]

Well over a decade.

The fundamental problem with ion thrusters (as a general class) is that you trade power use for fuel use.

Yes, they may use lots less fuel.
http://en.wikipedia.org/wiki/Specific_impulse#Examples - for example.

An advanced ion thruster may use nearly 1/50th of the fuel of a conventional rocket engine.
But, it needs 50 times the power to do this.

So, to replace a conventional rocket engine burning a kilo of fuel a second, and producing a thrust of perhaps 500kg, with no electrical requirements, you need about 20 grams of fuel a second, and around 450 megawatts of power.

Needless to say - for many applications, the power plant ends up heavier than the engine it's replacing.

It only works in very low thrust applications.

The low thrust also brings other problems.
For example, around the earth is a belt of charged particles.
Ascending through these on conventional rockets is not a problem. You do it so rapidly.

With ion engines, you need to slowly spiral out (due to being power limited), and your whole craft gets highly irradiated.

Re:How is this new?

[hrshea]

This ion thruster is unique by its extremely small size. we have miniaturized not only the ion emitter, but the entire thruster including high-voltage electronics and tank. Our complete thruster has a mass of 200g (including 100 ml of fuel), thus allowing it to be used on nanosatellites. It is the first high efficiency electric propulsion system that can be used in cubesats and 5kg satellites, such as those being planned for OLFAR The principle of operation of colloid thruster a bit different from the ion engines used fro instance on SMART-1, which uses ionize Xenon. in our case, we use a particular conductive liquid, an ionic liquid, from which we can extract both positive and negative ions. using a liquid avoids a pressurized tank, and allows for important simplification of the system (no valves, no heavy tanks, all flow controlled by capillary and electrostatic forces. using the ionic liquid allows the same speed as using a gas, but offers one big advantage: since we emit (from 2 chips in parallel) both positive and negative ions, the spacecraft stays electrically neutral, which is essential for electric propulsion to avoid having the ions fly back to the spacecraft. for more conventional electric propulsion systems, only positive ions can be emitted, so a neutralizer is needed to emit electrons to keep the spacecraft charge neutral. not having a neutralizer allows significant mass and power savings.
I'm biased, 'cause I work on this!
http://lmts.epfl.ch/microthust
- Herb Shea

Ion engines are already pretty efficient...

[Metricmouse]

and that is not the big issue, as getting off the ground is always the big expense, but we all know that. This tech can be useful in reducing weight costs for sub orbital payloads though, and probably resembles the design of a DS4G engine. The problem with efficiency in the past is that motors required high voltages to accelerate the ions that collided with the electric field grids. DS4G used a two stage four line grid with the top grid closely spaced and of higher voltage, with an open spaced lower voltage bottom grid. These differences between these stages allow higher velocity without ion grid collision at overall lower voltages resulting in 4x the fuel efficiency of previous engines.

Re:How is this new?

[queazocotal]

Well - yes, and no.

The fundamental problem with microwaves is - they're microwaves.
They are just another sort of radio, and like all radio waves, and light, and ... - they undergo diffraction.

This limits how much you can focus them.

A 'small' transmitter antenna of say 1km, with microwaves of about 10cm wavelength, will have a beamwidth of about:
1.22*.1m / 1000m.
This is a beam which spreads about one part in ten thousand.

After 10000km, the beam will be one kilometer in diameter. At the distance of the moon - 40km.

So, you need an antenna 4km in diameter on your craft simply to pick up one percent of the beam at the moon.

Range is a major problem.

Lasers work somewhat better - but have their own annoying issues.

Parent link is bad. Try this -

[Frosty Piss]

Parent link is bad. Try this:

http://lmts.epfl.ch/microthrust