Name: 可以將人類送上火星的電動推進器 (The Electric Thruster That Could Send Humans to Mars)
Uploaded: 2021-01-14T10:27:36.000Z
Duration: 6 min 24 s
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When you imagine humans on their way to Mars,

you probably imagine them in a spacecraft with big, explosive, chemical engines.

Humans need to travel with a lot of stuff,

and engines that rely on chemical combustion are currently the only ones powerful enough

to move us through space at a reasonable speed.

Except, chemical engines also have a pretty big downside.

which makes their spacecraft super heavy.

And that leads to more expensive missions that are harder to launch.

Honestly, it would be nicer if we could move humans with a lighter,

We might have already found our best option.

It's a form of electric propulsion called a Hall-effect thruster,

They're thrusters that look a bit like a bullseye

And they could be the future of human space exploration.

Unlike some of the ideas we talk about on this channel,

Hall thrusters aren't theoretical — or even new.

and engineers have spent decades advancing the technology.

these thrusters work by accelerating charged particles called ions.

First, you start with a circular channel —

or a few channels, depending on how big your thruster is.

you put some magnetic coils that generate a magnetic field.

you add an electrically-charged plate called an anode,

which is located somewhere outside the channel

the cathode starts releasing those electrons.

The particles are attracted to the anode, so they go flying into the channel.

There, they're caught up in the magnetic field

and start zooming in circles around and around the thruster.

Hall thrusters pump a bit of propellant into the channel —

The xenon gets hit with all of those incoming electrons,

and that knocks off some of its electrons and turns the xenon atoms into ions.

The electric field inside the thruster then pushes those xenon ions out of the channel

sometimes more than a dozen kilometers per second.

And that's what generates the thrust to move your thruster and your spacecraft forward.

Now, this basic idea of accelerating ions isn't unique to Hall thrusters.

Every form of ion-based electric propulsion does something like this.

is that they satisfy three major conditions.

For one, they have among the highest thrust of all forms of electric propulsion.

but one is because the propellant ions are created

Other thrusters keep these processes separate,

and there's a limit on how many charged particles they can cram into one spot

before the electric field gets messed up.

Hall thrusters also use their fuel really efficiently.

Since they accelerate their ions to such high speeds,

they generate more thrust for every molecule of propellant they use.

And finally, they can fire for a long time.

Other ion thrusters have components that quickly wear out,

and while Hall thrusters do have their own lifetime problems,

engineers have found ways to solve or mitigate many of them.

So in the end, these thrusters can fire for much longer,

which means they're a lot more practical for spaceflight.

Since the '60s, Hall thrusters have flown on dozens of missions.

Mostly, they've been used to adjust satellites' orbits,

but in the 2020s, they'll be used on even bigger projects,

like the Psyche mission to investigate an asteroid.

But earlier, I said Hall thrusters could be the future of human space exploration.

well, they're nowhere near strong enough to push around people at a helpful speed.

Because here's the thing about Hall thrusters —

Their main benefit is that they can fire for a long time.

That means though you might start off slow,

you can gradually build up speed until you're zooming along faster

than any spacecraft that uses chemical propulsion.

The problem right now is that getting to those speeds takes a long time.

With our current tech, it would take years to get people to Mars.

Because there's a Hall thruster currently in development

that could become strong enough to move humans.

and it gets its name because it has three channels instead of the more common two.

This allows it to accelerate more ions at once.

It's still nowhere near strong enough to fly humans,

even if we put several of them on the back of a spacecraft.

But, it has generated more thrust in a test than any other Hall thruster.

Now, engineers are working to make X3 more reliable and increase its thrust.

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可以將人類送上火星的電動推進器 (The Electric Thruster That Could Send Humans to Mars)

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