I'm looking for a credible technology which could be used as a shield for a spacecraft sometime within the next 100-200 years.

Not necessarily a spherical shield which covers the whole ship, it would only need to sweep aside micrometeorites and other debris, much like the way the bow of a ship cuts through water. The higher the velocity of the ship, the more water is displaced.

Another analogy might be the way that the Van Allen belt diverts radiation to flow around the Earth.

If it can refract laser light so that it doesn't reach the ship itself, but bends around it, that would be a win as well.

The idea of an almost solid shield which has missiles, fighters, small planets etc. exploding uselessly against it is not really what I'm looking for. But by all means, if that might be feasible I'd be all for it.

Another direction might be to have a superheated plasma around the nose of the craft which burns through micrometeorites.

Or something else that is able to convert the kinetic energy from the velocity of the micrometeorite into enough heat to destroy it before it can do any damage.

My approach to this is that larger objects could be detected at a distance and avoided wit only a small evasive manoeuvre, but micrometeorites would be more difficult to detect in time.

The spacecraft is to operate away from any large planets, in the asteroid belt. Lots of dust and debris, but no large gravitational masses around, except the larger asteroids.

EDIT: @Jim2B suggests that the four known forces would be unlikely to help in the way I would like. Any other options? Remember, this has to be credible, not necessarily factual with current technology.

  • 1
    $\begingroup$ One thought is to direct the material into an 'engine' to help fuel the ship, like a large ram jet. I'm sure the answer is yes to your question, but I'm not firing on all cylinders this morning. $\endgroup$
    – bowlturner
    Dec 18, 2015 at 14:51
  • $\begingroup$ Yes... Didn't think of that. I'm kind of tending towards an ion drive for this ship, but I am a fan of ram / scramjets in general. $\endgroup$
    – Smoj
    Dec 18, 2015 at 14:57
  • $\begingroup$ This is really a duplicate which has an answer that fits this post well. $\endgroup$
    – JDługosz
    Jan 3, 2016 at 18:51

3 Answers 3


See my earlier answer on Hard Sci-Fi Energy Shields.

My superconductive swarm uses electromagnetism, as does a particle fountain. So EM affecting matter makes a shield, not EM alone.

I could paste that answer here exactly as-is, as it fits this question exactly.

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    $\begingroup$ I hadn't seen that question and answer previously, but it fits nicely. $\endgroup$
    – Smoj
    Jan 3, 2016 at 19:05


In order to block or repel incoming damage, you need a repulsive force. Of the Universe's 4 known forces (Strong, Weak, Electromagnetic, & Gravity), only the Weak Nuclear force is always repulsive and the EM force is conditionally repulsive. The Strong force and Gravity are always attractive (you do not want this).

Weak Nuclear Force

Despite its name, the weak nuclear force is really quite strong. The problem is that its strength declines very rapidly with range, making it effective for this sort of job up to a distance of only $10^{-18}~\mathrm m$. Much beyond that distance there's no measurable effect of the Weak Nuclear Force.

Electromagnetic Force

Although Electromagnetic can be repulsive and is quite strong, it requires the incoming ordnance and target to posses the same charge polarity (e.g. + & + or - & -) or the EM force does you no good (and might actually attract the incoming ordnance if you get the charge wrong).

A Special Exception

If you know ahead of time that the object is charge and what the charge of the incoming object is (such as the Solar Wind is always "+" charged), you could generate a magnetic field around your ship that would divert the incoming particle stream around the ship.

You can enhance this effect by filling the magnetosphere of your ship with like charged particles (the same charged particles will repulse the incoming particles).

This "shield" would be a highly effective radiation shield to protect your crew from a Coronal Mass Ejection but it would not help much in combat.

  • $\begingroup$ I guess that's not really the answer I was looking for. Not arguing with its correctness, just needed to hear something different :-) $\endgroup$
    – Smoj
    Dec 19, 2015 at 1:13
  • $\begingroup$ What about an ablative layer of plasma? I'm thinking like a boundary layer of some gas, that converts kinetic to heat energy? $\endgroup$
    – Smoj
    Dec 19, 2015 at 1:37
  • $\begingroup$ As far as knowing the charge of a piece of dust in space goes, would said dust particle pick up a static charge in a near vacuum? I'm assuming that friction would be very low as it bumps against the only very occasional atom or molecule... Would the solar wind impart a charge to the particle? Combat would be a secondary consideration, a bonus. $\endgroup$
    – Smoj
    Dec 19, 2015 at 4:02
  • $\begingroup$ If you help yourself to some serious future magic, you can get a better electromagnetic shield by alternating positively and negative charged layers. It could keep anything from asteroids to alpha particles to beta particles away from your ship. Problem is, that which can get through the outermost layer isn't deflected, but captured. Not an enormous problem for future magic, you just turn off your shield in a safe region of space, shake off the junk, and keep going. But amusing, still. $\endgroup$ Dec 19, 2015 at 5:57
  • $\begingroup$ @SudoSedWinifred Interesting idea... All the trapped detritus and debris might also help absorb some of the energy of a moving particle as well. $\endgroup$
    – Smoj
    Dec 19, 2015 at 7:57

The use of plasma, probably. Should the plasma flow, there would be a current (the gas would be ionized and thus carrying a charge), and should that current be in the presence of a magnetic field, there would be a force acting on the current, in this case plasma... and I hope my understanding of this is correct.

The plasma might be ejected from the ship and could knock aside minor debris.


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