Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Using a Ionocraft (lifter) to get into space

  1. Dec 18, 2007 #1
    I was thinking that a large scale ionocraft in theory could be built to reach space. An EHD (Electrohydrodynamics) thrusting device of this scale would need mammoth amounts of high voltage electricity that couldn't be practically fed via cables, however is there not a way to transmit the required power via radio or laser or some other medium that I havern't considered?

    So far the main problems I can see are:

    1) Generating enough power
    2) The weight of the lifter
    3) Perfecting the design to increase controllability
    4) Finding a practicle means to transmit the power without cables
    5) The altitude at which the thrust becomes insufficient to continue to accelerate the craft (hopefully the velocity by that time will be suffcient to reach orbit!?)

    The principles and concept behind a lifter are very simple but I am not sure if it has been considered as a potential space propulsion.

    Does anyone have any clever ideas how this could be achieved? Or if it is not possible, then an explaination as to why?

    Thanks
     
  2. jcsd
  3. Dec 18, 2007 #2
  4. Dec 18, 2007 #3

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    Electrostatic lifters are inefficient, I suspect it would be a very bad way to try and lift something into orbit. Heck, lifters can't even be used to "lift" any sort of appreciable payloads. You DID pay attention to the part where a lifter only works in air, right? You wouldn't be able to get into orbit for the same reason you can't use a jet or balloon.

    I think you are making a mistake that many people make coming here for answers on getting to space; specifically that it isn't height that get's you into orbit, its speed (a.k.a. specific energy). To get to a circular orbit at 160 miles up, you need about 30 MJ/kg of specific energy (that's 30e6 joules of energy for every kilogram of weight), which works out to about 7.7 km/s.

    Just becuase you lift something to a height of 160 miles doesn't mean you're in orbit. If you aren't going 7.7 km/s you're toast and will fall back down.
     
    Last edited: Dec 18, 2007
  5. Dec 18, 2007 #4
    http://www-personal.umich.edu/~reginald/liftvac/Clip273.mpg

    Yeah I am being told that it can only work in the air but I have also found people claiming and demonstrating that it can work in a vacuum. The video above for example.

    Either way the atmosphere can reach beyond 40km giving the craft time to accellerate. Even if it could only be done without a payload, it still would be impressive. If it can work in a vaccum as some accounts and videos seem to suggest then surely the system could just be scaled up.

    Has anyone here tested a lifter in a vacuum?
     
  6. Dec 18, 2007 #5

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    That video proves nothing, it is not possible to determine if the lifter is actually in a vacuum, or the unknown videographer is simply saying that. Just looking at the "vacuum chamber" in the video disproves the claim, it's clearly made of plexiglass. Did you read your own wikipedia link?

    No, this isn't true. There presently isn't any way to launch a craft into orbit using atmospheric thrust alone. Not even SCRAM jets or the like can get going fast enough. And 40km (24.8 miles, 131k ft) is far short of orbit. Besides, no flying craft ever built has been able to get anywhere close to escape velocity while still in the atmosphere, not even close. 7.7 km/s (low orbit velocity) is MACH 23 at sea level.

    I don't think there has never been a lifter that runs off of it's own power (i.e. doesn't have an umbilical connected to some power source on the ground.) And not everything can simply be scaled up as you hope.
     
    Last edited: Dec 18, 2007
  7. Dec 18, 2007 #6

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    Your fundamental question has been answered-

    1) Lifters only work in a fluid (air).

    2) A lifter does not produce enough thrust to lift anything other than itself and a very lighteweight frame. No power supply, no nothing.
     
  8. Dec 18, 2007 #7

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    Fun facts-

    A spacecraft which is hypothetically accelerating to a conservative orbiting velocity (7.7 km/s) in the first 40km of the atmosphere would have to accelerate at a constant 741 m/s^2, or 75.5g, for 10 seconds. Not a chance in heck for any human to survive that, and it's doubtful any lightweight spacecraft could either.

    For escape velocity? It would have to accelerate at 1,568 m/s^2, or 159.8g.

    So, say a spacecraft weighing in at a scant 100kg is accelerating to 7.7 km/s in the first 40km of the atmosphere. It would require 74,000 N of thrust not including air resistance (which would be incredible at those speeds). Power requirement for that kind of acceleration: a paltry 285 MW, as in 285 MILLLION watts. Accelerating to 11.2km/s in the same distance would only take a little bit more at 878 MW total.

    Basically, the "ship" would turn into an inverse meteorite, burning up in the atmosphere, and throwing it's superheated plasma into space.
     
    Last edited: Dec 18, 2007
  9. Feb 17, 2010 #8
    I think all of you are not looking at the big picture, all things have a beginning until its mastered and then shrunk, the first problem with the lifter theory its still in mental building stages,no one got the kinks out yet let alone understand what they are,(that tube won't fly,ha.ha..ha) that's probably what the wright brothers heard over and over and it didn't stop them,2 minute flight lead to flights around the world.Second problem is the power supply its being done all wrong what happened to fuel cells to produce pure electricity, not heavy batteries and old style power supplies,How can you complain about something new when everything is done with an old mind set..
     
  10. Feb 17, 2010 #9

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    It's you that isn't looking at the big picture. How do you propose to use a lifter for space launches when it only works within the atmosphere and it's effectiveness reduces and the air density does?
     
  11. Feb 17, 2010 #10
    Technically no one has proved that it doesn't work in vacuum they just use that excuse as a way of discrediting the possibilities,First propellers don't work in a vacuum, but they did open the door for turbo,then jet,then rockets.So if the nay say's stop trying to prove it doesn't work, and focus more on the fact that something is happening instead of trying to tell people it's snake oil.Second it seems that maybe if you would experiment with the gap between the two main electrical components and had a way to micro adjust that gap that might aid in performance,using different materials more work,remember no one truly did any thing new since the original inventor of the idea, so how old would that make it.So now were in 2012 and were using 1900's materials for something that was ahead of its time then.Finally use a energy source that creates it's electricity instead of batteries, Cars crate their energy threw the engine, and before you say gasoline, remember hydrogen,Third just like all the sic-fi that i know you watch never did one ever use one engine for atmospheric travel and then to space,Multiple engines and that's why electricity is the best which, Ionic thrust, VASIMRs,Plasma,Magnetic pule thruster.Electricity the most abundant source of energy in the universe
     
    Last edited: Feb 17, 2010
  12. Feb 17, 2010 #11

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    Wrong. The method in which lifters work is an understood phenomenon, and has to do with ionizing the air surorunding it's electrostatically charged poles. THEY DO NOT WORK IN A VACUUM.

    Also wrong, first because you got the order of those inventions wrong, but also because rocket technology used in space has nothing to do with a propeller. An ESD lifter cannot be used to provide thrust in a vacuum.

    So, you want us to just assume it will work, when in fact I've already presented why it can't? You've obviously made the assumption (erroneously), but I am not going to go down that dead-end path.

    How is adjusting the distance between the dipoles a quantum leap in the technology used in the past? You can buy a $10 kit to make an ESD lifter, what's stopping you from making one and experimenting?

    There are no sources of energy that "create" it. Batteries are a form of chemical energy storage, gasoline is another form (and usually used with combustion), hydrogen is another form. Whatever form it takes, you're carrying a set amount of energy in a stored form.

    So now you're proposing using an ESD lifter to lift into the atmosphere, and then use a different drive to launch into space? What we've been arguing the whole time here is you cannot use an ESD lifter to launch into space... but even if you were only using it in the atmosphere I've only seen ones that lift a few ounces (and they don't carry their own energy source).

    No it isn't. I would argue that heat is (or possibly mass itself, E=MC^2 after all).
     
  13. Feb 17, 2010 #12

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    Note the title of this thread- "Using a Ionocraft (lifter) to get into space." What do you suppose the root meaning of "ionocraft" is? Perhaps that it IONizes air, and therefeore requires air to operate?
     
  14. Feb 18, 2010 #13
    Ionized Ions{ Ions are atoms with either extra electrons or missing electrons}, not air: If you can't say yes just say Nay...
     
  15. Feb 18, 2010 #14
    I like this debate. I would have to say that I had to do a little research on lifters. I agree that it doesn't seem likely that this will ever take us into space, and the ionized particles are not good for our health (O3, NOx), thus that is a limitation that also has to be overcome. But I do agree that there are emerging technologies that can make it more reasonable. And as an engineer and science-enthusiast I have to accept the possibility that tomorrow or some time in the future someone will discover something that will change all. If the force created by the motion of the ionized particles is too chaotic and lossy, then someone has to figure if its possible to control the molecular interactions to an optimal level and then see how much more thrust that generates. In terms of power and weight requirements, I don't know. That's the beauty of it.

    I would argue that if ionization ever gets realistic, we'll first see flying cars and things like that, that are not intended to reach such extreme exit velocities.

    VASIMR is another engine technology that uses gas ionization but in a different way. Not O2 (usually). And it uses a high frequency generator to agitate the molecules into a plasma state and with magnets the plasma is directed out and thrust is created. We'll see if it works in a couple of years when they test it in the ISS.
     
  16. Feb 23, 2010 #15
    OK not to beat a dead horse but back to the what if. I'm no physicist just thinking, now the ion wind effect doesn't produce enough thrust to completely explain the lift effect, so what if the ionization is a by product of the electrical charge some how affecting the electron and releasing an uneven balance of electrons and protons causing some type of manipulation of neutrons thus affecting mass.Just wondering...
     
  17. Feb 23, 2010 #16
    to add, is it necessary to have high velocity to gain escape earths gravity, would a constant stead lift not work as well, like high altitude clouds,or air molecules leaving a planet there's no thrust.
     
  18. Feb 24, 2010 #17

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    The "ion wind effect" as you describe it does account for the total amount of lift experienced by an lifter. Asking "what if" doesn't get us anywhere because there are no physical phenomenea at work other than thrust (just because you aren't a physicist doesn't mean you shouldn't think logically).

    To break off protons and neutrons, you would need to have a particle accelerator accelerating the electrons to very high energies. A little high voltage won't get anywhere close, and even if they were the "manipulation of mass" you're describing wouldn't produce lift, just a lot of radioactivity.

    This is a common misconception- height can get you into orbit. It isn't height that will allow you to achieve orbit (or escape velocity) it's speed. Unless you have a specific energy of around 30 MJ/kg (roughly equivalent to 7.7 km/s), you will fall back down. I have already covered this issue in this very thread!
     
    Last edited: Feb 24, 2010
  19. Feb 24, 2010 #18
    Thanks for the insight as sarcastic as it is, but lets continue...To be continue
     
  20. Feb 28, 2010 #19
    Where's my boy,the back & forth is a good brain exercise.For the record I'm up to my fifth lifter nothing fancy just a basic interchangeable parts;I made it like this cause i seen some ware when the changed the wire material like stainless steel instead of copper and had different effect,The ozone(back to the what if),might be creating a bubble cause the wind does not account for lift...Acceleration is not the only way to escape a planets gravity.Gravity,time,Space are all intertwined.Not to get to off topic birds fly and float and yet that don't relate to your equation,what I'm saying is this is infant new & if science ruled we would be on the moon since J.F.K,we need to address things from a scientific perspective, Analise debate then theorize, meaning constructively challenge the possibilities,not recite facts, science is about the unknown not the known.The earth was flat(known @ the time),the earth was the center of the universe.Space is a vacuum,if you have something that works on electricity as a propulsion source and if better tested voltage might not be as primary as we think,(think,unknown) & we put some real thought to it then we might have something.
     
  21. Feb 28, 2010 #20

    russ_watters

    User Avatar

    Staff: Mentor

    This thread has run its course. Locked.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Using a Ionocraft (lifter) to get into space
  1. Demistifying lifters (Replies: 6)

  2. Lifters ? (Replies: 6)

Loading...