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Ion Engine Interactive

Inside this Ion Engine, the red (+) and blue (-) grids are charged to different strengths. The charge differential between these grids accelerates the ions, producing thrust for the spacecraft.

Your Mission:

Design your ion engine by adjusting the separation between the two grids and the strength of the charge on the grids to achieve maximum impulse, so that the spacecraft (shown at the top of the display) will go as far as possible.

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Welcome to Ion Engine! Adjust the Grid Location and Grid Charge, and then press the Launch button.
Grid Location:
Grid Charge:

Your Controls:

  • Adjust the Grid Location control to change the grid separation distance.
  • Adjust the Grid Charge control to change the charge strength on each grid.
  • Click the LAUNCH button to start emitting electrons from the blue electrode. Watch the red ions accelerate toward the blue grid and shoot out the back of the Ion Engine.
  • Click the STOP button to reset the simulation and try different grid settings.

Things to Notice:

  • The green particles are xenon atoms, which are neutral in charge. They float around the chamber, unaffected by the charged grids. When an electron from the blue electrode hits a xenon atom and knocks an additional electron off, the xenon atom becomes a positive (red) ion.
  • Notice that the red (+) ions drift toward the grids. The acceleration of the ions occurs between the two grids. If the separation between the grids is not adjusted correctly, too many ions will hit the grids. These ions will not accelerate the spacecraft.
  • Once a xenon particle leaves the spacecraft, it cannot be re-used. Since the spacecraft carries a limited supply of xenon, once it's gone, the Ion Engine stops working.
  • If an ion or electron hits a grid or the walls of the Ion Engine, it will emit a brief white flash and disappear.
  • Increasing the charge on the grids means that the ions are accelerated more and there is more thrust. Remember that the energy to do this comes from the spacecraft's solar panels, which is limited.
  • Adjusting the charge too high might make your Ion Engine run out of energy before enough ions can be accelerated for propulsion.
  • Adjusting the charge too low means the grids won't accelerate the ions with as much force.

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