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#1 2014-06-27 05:58:03

Void
Member
Registered: 2011-12-29
Posts: 6,976

Ion Electrospray Propulsion System for CubeSats

http://www.space.com/26356-time-capsule … ystem.html

http://web.mit.edu/aeroastro/labs/spl/research_ieps.htm

Apparently emittng salt particles is more efficient than emitting gas.  This is currently for small systems, but does not rule out use for human space flight eventually.

I don't actually have any important technical knowledge, and it is perhaps a stupid notion, but perhaps emitting fine dust will not be ruled out eventually?  In that case dust from Asteroids, the Moon, Phobos, Demos?  But they are using salt.  A more efficient (Collection of tiny engines) that emits particles of solid materials though is somewhat of a new path though.  I am interested.

Nano scale machines having been proposed in technology, I would not say that it is forever impossible.

Drawing on knowledge provided by others here and adding my own speculation, I wonder if ion propulsion of particles could eventually be combined with magnetic mass driver technology.

Giving particles a kick with both electrostatic and magnetic forces.  I understand that ion engines already involve magentic fields (Or I think so), but perhaps not pulsing magnetic fields.

So to make a superior dust, I suggest using the Mond process to create a liquid from Iron and Nickle, and then using a spray paint process to create tiny beeds which would condense to solid before impacting a wall, and would have some magnetic properties.  Making things more complicated, perhaps non magnetic materials could be deposited on the outside of these very tiny beeds, to add mass, and to utilize non magnetic mass.

In the propulsion process then, some kind of a nano scale conveyor process to feed them at a prefered rate into a combined ion/magnetic mass driver engine(s).

Last edited by Void (2014-06-27 08:15:48)


Done.

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#2 2014-06-27 09:37:59

JoshNH4H
Member
From: Pullman, WA
Registered: 2007-07-15
Posts: 2,538
Website

Re: Ion Electrospray Propulsion System for CubeSats

I think the idea is that liquid salts already respond to electric/magnetic fields because they are already ionized.  I don't know if this will be any more efficient or have a higher Isp than ion drives, but I love that it's more compact, and I bet it has a higher trust to weight ratio.

A couple of days ago I tried the calculations for a mass driver used as a rocket engine to get to orbit.  It would be great, but the thrust to weight if a mass driver may never be high enough.  I don't know if this will be part of an eventual solution, but it sure is a good idea.


-Josh

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#3 2014-06-29 23:21:48

idiom
Member
From: New Zealand
Registered: 2004-04-21
Posts: 312

Re: Ion Electrospray Propulsion System for CubeSats

Ionized salt is different to iodized salt right?


Come on to the Future

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#4 2014-06-30 00:07:37

JoshNH4H
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From: Pullman, WA
Registered: 2007-07-15
Posts: 2,538
Website

Re: Ion Electrospray Propulsion System for CubeSats

Yes, absolutely.  All salts are composed of ions, whereas iodized salts refer specifically to salts containing iodide ions, meaning salts of iodine.


-Josh

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#5 2014-07-02 21:54:50

idiom
Member
From: New Zealand
Registered: 2004-04-21
Posts: 312

Re: Ion Electrospray Propulsion System for CubeSats

I thought I was funny. There isn't enough funny on this board.


Come on to the Future

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#6 2014-07-03 11:52:55

JoshNH4H
Member
From: Pullman, WA
Registered: 2007-07-15
Posts: 2,538
Website

Re: Ion Electrospray Propulsion System for CubeSats

As you can perhaps tell, I'm not known for my sense of humor smile


-Josh

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#7 2014-07-07 08:06:04

Void
Member
Registered: 2011-12-29
Posts: 6,976

Re: Ion Electrospray Propulsion System for CubeSats

So, can we catch comets by putting salt on their tails?

I have been thinking about the fact that you have reasonably accepted salts as propulsion mass, in association with the ion thrusters referenced in
this thread.

I always hope for a way to procure mass from non-Earth objects in such a way to be helpful to the cause.

Moon dust being the most easily obtained portion of Lunar resources, and many salts apparently being partially composed of metals, I see a
potential.

This also could be done from the moons of Mars, and of course Mars itself has salt pans, and salty soils.

Don't know if these thrusters can use NaCl, but I do know that there is Sodium and Chlorine on the Moon.  I don't know if much Sodium is in the dust,
and I don't expect much Chlorine in the dust, but I do believe that there are other metals that could be used to in part create salts.

I would have to suppose that the Chlorine would have to come from Earth, and possibly Mars, or a substitute for Chlorine which would also make
usable salts.  I am sure getting Chlorine or Fluorine into orbit would be a have some danger involved.

There are also Iron Salts (Which I don't know are or are not usable)

http://www.sigmaaldrich.com/materials-s … e=19295340

Magnesium Sulfate looks interesting since it has less dangerous components, but I of course do not know if it is suitable for this propulsion
system.

http://en.wikipedia.org/wiki/Magnesium_sulfate

Anyway, if it is a good propulsion system for some aspects of space travel, then perhaps some components of the salts can be obtained off planet,
at a reasonable cost very soon, and then of course with a more advanced space industry (If ever), perhaps all the components could be obtained, from
the Moon, and then other locations.

Of course Mercury, Europa, and Enceladous likely have those, but that would be very very advanced space industry.


Done.

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#8 2014-07-07 11:45:30

JoshNH4H
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From: Pullman, WA
Registered: 2007-07-15
Posts: 2,538
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Re: Ion Electrospray Propulsion System for CubeSats

It's important to note that the salt can't be in its solid form, but has to be a liquid.  Conductive objects, in general, respond to magnetic fields.  Objects conduct electricity because they have charged particles within them that can move.  In metals, these mobile charged particles are electrons.  In molten salts, they are the ions themselves.  In solid salts, the ions can't move and so they don't conduct electricity.

The Moon is made from the same material as Earth, and therefore I would expect it to have similar salts as Earth, although it is unlikely that things will be concentrated because salts are typically concentrated in dried seabeds


-Josh

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#9 2014-07-07 12:45:01

Void
Member
Registered: 2011-12-29
Posts: 6,976

Re: Ion Electrospray Propulsion System for CubeSats

I agree that salts might not be in a easily collectible form or very abundant on
the Moon.

I do think that it might be considered to manufacture salts in part from Lunar or
other sources.

Probably some of the components would have to come from Earth, at least initially,
for economic reasons.

I think that just picking up the dust of the Moon is the first easiest mining
that could be done, and it could be largely automated.  But that would not
procure all of the chemicals to manufacture salts.  (But it might be preferable
to bringing all the mass up from the Earth).

This propulsion system is just a contender, and might be discarded for something
better, but if it is considered useful instead, then obtaining salt mass to
expel has to be of interest, and obtaining it from the Moon would be transferable
to other solar system objects in many cases.

*Even though the salt may be liquid, the article indicated that expelling particles.
I presume that the liquid becomes a spray, and at that point those particles are
expelled.

But I will leave it there, I have passed my ignorance limts on this one.


Done.

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#10 2014-07-07 13:45:13

JoshNH4H
Member
From: Pullman, WA
Registered: 2007-07-15
Posts: 2,538
Website

Re: Ion Electrospray Propulsion System for CubeSats

Well, it seems to me that salts may indeed become the propellant of choice for electric propulsion drives.  It'll sure be nice to save the energy of ionization that you have to deal with when you use gases.  Then again, perhaps electric drives will in the future take the form of a mass driver, in which case it won't matter what you use as propellant.  I don't really know!


-Josh

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#11 2014-10-13 12:03:33

Antius
Member
From: Cumbria, UK
Registered: 2007-05-22
Posts: 1,003

Re: Ion Electrospray Propulsion System for CubeSats

I like the idea.

Practically any material could be used as fuel in an ion rocket.  Pellets of compressed lunar dust could be used as propellant if doped with a conducting material such as iron.  The pellets would be fired into a chamber surrounded by a powerful induction coil and heated to several thousand degrees centigrade.  At this temperature, the material will convert into a plasma.  All ionic materials (of which the moon is exclusivley formed) become electrically conductive when molten, so the amount of conducting 'dope' required should be relatively modest.  Carbonaceous asteroids contain substantial elemental carbon and iron, maybe allowing unbeneficiated regolith to be compressed and sintered into pellets and used in this way.

Following ionisation, the plasma could then be accelerated by an electric field.  The induction coil would create a sufficient magnetic field to hold the plasma away from the reaction chamber walls.  The anode would be in the form of a carbon plate at the top of the chamber.  The cathode would be a carbon fibre wire mesh stretched across the exhaust orifice.

The induction coil would be virtually 100% efficient.  If there were an adequate electric power source (fission fragment reactor?) the device could even be used in high thrust mode if specific impulse were less important, i.e. takeoff from an asteroid.

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#12 2014-10-13 13:47:45

Void
Member
Registered: 2011-12-29
Posts: 6,976

Re: Ion Electrospray Propulsion System for CubeSats

I really think I am outliving my worth on this site, but in the absence of other replies, I will simply say I like your attitude.

But it is beyond my level.  I will spare others the need to educate me on that.

I had tried to think of a method of a DC magnetic field where magnetic particles would drop into it.  The field might drop into it and before loosing momentum by passing back up the other side of the field, they would become non magnetic.

That might be done by burning them in Oxygen.  But I just can't fathom the counter reactions, what happens to the magnetism, passing the Curie point, and also becoming a different molecule?

The field might be pumped up by pushing electricity though a existing plasma bubble?

http://www.sciencedaily.com/releases/20 … 131156.htm

But that might blow the plasma bubble apart?  Or would it compress it?

Anyway, that one went back into the abyss of my mind, and just not drawn to it.  Probably won't be.  Think I am going to retire my mind before I damage it trying to do heavy lifting.

What's this going to do with previous dialog?  Well, I thought of a combination, but that's not looking clear to me just now.

The common desire, of course is to push mass out of a ship with as much energy as possible, and go like a bat out of hell.

But I only have fallow fields and sawdust in my coconut just now.

With that I withdraw. 

My brain is full smile


Done.

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#13 2014-10-13 18:51:28

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 28,750

Re: Ion Electrospray Propulsion System for CubeSats

Water is still the key to making the salt work as that is what makes it liquid for the ION engine to work with. I do believe the other salt types would work equally as well.

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