I don’t think so. Anyhow, their low thrust, high ISP output is already useful for continuous, long acceleration - like during the Dawn Mission - saving lots of fuel.

Ion thruster and chemical rockets are for different purposes. I don't think they'll ever replace each other for the roles they are designed for.

Ion thrusters are good for control when in space (like controlling the movement of a satellite) because it doesn't need large solid fuel reserves to operate, but it's also not strong enough to push through the atmosphere.

Chemical rockets are powerful enough to push through air, but they take too much fuel and burn too uncontrolled to be useful for control once in space.

> Can a Ion Thruster ever Match the Thrust of a Chemical Rocket?

In theory, sure, but in practice the VASIMR project is trying to approach that threshold and already has numerous drawbacks.

Haven't heard much out of them lately though, and the power requirements make it pretty impractical.

And that power requirement is always going to be an issue with electric thrusters: objects in LEO have about 32MJ of energy per kilogram vs an object sitting on the earth, and launch to LEO takes about 8 minutes, so you're looking at 67MW per ton (first approximation crude napkin math) with even a 100% efficient ion thruster just to match already existing rockets - and I don't think we have any source of electrical power that gets anywhere near that requirement.

As a cross-check, this post says Falcon 9 is pushing 26GW at launch, and with its ~545 metric ton launch mass, that's 47MW/ton so apparently my napkin is a bit off, but well within an order of magnitude.

Seems like we're gonna be sticking with chemical fuels for a while, and using ions for more sedate in-orbit maneuvers where a small thrust for a long time is just as useful as a lot of thrust for a short time.

While there have been recent breakthroughs in improving the thrust of ion drives, they and all other electric rockets still invariably have inferior thrust when compared to chemical rockets.

That doesn't mean they aren't competitive, however, or that there are not drives with decent thrust.

Magnetoplasmadynamic drives, for instance, could boast better thrust and specific impulse than existing electric rockets, and some electro-thermal rocket motors coule have impressive thrust at the cost of specific impulse.

However, higher performance electric rockets in turn require more electricity and operating temperatures. While this may require the use of nuclear power plants per given mission requirements (increasing cost and vehicular mass), their higher specific impulse relative to chemical rockets means they could employ higher energy trajectories and ultimately get to their destinations faster for less propellant.

Some kinds of nuclear rockets can also rival chemical rockets in terms of thrust, but they also tend to be very heavy (courtesy of the reactor and shielding) and expensive. Nuclear thermal rockets have been tested on Earth, though, and NASA has recently shown renewed interest in their use.

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In theory an ion thruster could go faster than a chemical, it just takes much longer for the ion thruster to get up to speed.