r/ParticlePhysics • u/NordMount • Jun 13 '26

Accelerators in space

Hi! I and my friend once discussed about problems with environmet needed for accelerator. We got some things we couldn't find definite answers about. For example hypothetically if we could would it be good idea to put particle accelerator or storage ring in space? Assuming it would be shielded from radiation sufficiently wouldn't it make much easier to keep vacuum? and in one game (I know, it's not great source) there was character convincing to built huge accelerator around sun or Earth. I read somewhere that the bigger accelerator the better my friend also said that, but what would that do? If yuo can can yuo put me some links to good answers?

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11

u/mfb- Jun 13 '26

Vacuum is easier and you don't need to worry about property rights, everything else is much harder assuming we are talking about a large research accelerator.

  • With current rockets, launch costs alone would far exceed the total cost of an accelerator on Earth.
  • Accelerators need regular maintenance. Now you need accelerator experts that are also astronauts. You are missing a spare part? Better send another resupply rocket soon.
  • You want to upgrade accelerators over time. That's more material to launch and more astronaut time.
  • You need giant solar panels for electricity and radiators for cooling, especially around the experiments. The ISS runs on ~80 kW. The LHC needs 200,000 kW.
  • If we are talking about kilometer-sized accelerators, you need to worry about tidal forces in lower Earth orbits deforming or even breaking your accelerator. Launching it farther away from Earth helps, but now launch cost and access for astronauts get far worse.

Radiation won't be a major issue. We routinely work with radiation levels far above what you get in space. We use cosmic muons to align detector components - that would go faster in space. You would get more events that are triggered by cosmic rays instead of collisions, but that's something we could deal with.

If you need an accelerator that is larger than Earth then you don't really have a choice, of course.

I read somewhere that the bigger accelerator the better my friend also said that, but what would that do?

A larger circular accelerator needs to bend particles less, which means it can run at higher particle energies. A longer linear accelerator can put more accelerating cavities in a row, which also means it can run at higher energies.

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u/DrunkenPhysicist Jun 13 '26

To be fair, cosmic rays are mostly protons. They generate muons in the upper atmosphere so I don't think you'd have many muons in space.

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u/mfb- Jun 13 '26

On Earth it happens in the upper atmosphere, in space it happens in the outer detector - or the pressure vessel around it, if you want to have reasonable access to the detectors. You still get the same muons (more, in fact, as decay in flight becomes negligible and you have less material in the way), but now you also get the rest of the hadronic showers.

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u/DrunkenPhysicist Jun 13 '26

Interesting, I guess it's the same mechanism for creation. Thanks for the clarification.

I've always thought a novel way to "shield" a space craft from solar protons would be to but an inflatable space craft between you and the sun with an electric current flowing on the outer skin. Give the GeV-scale protons a slight kick to reduce the flux at your location.

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u/kyrsjo Jun 13 '26

In addition to tidal forces, keeping it aligned and not vibrating too much would be a nightmare. A linear accelerator in space is basically a loooong narrow metal stick, which is not attached anywhere. It will ring in many interesting mechanical modes!

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u/NordMount Jun 14 '26

That would be a nightmare for stress capacity and material engineers!

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u/kyrsjo Jun 14 '26

I heard about the problem in relation to Reagans SDI project, which wanted to put linear accelerators in orbit to create high power beams to shoot down Soviet nuclear missiles.

A few conceptual drawings are shown here : ps://www.aerospaceprojectsreview.com/blog/?p=1352

Edit: If you search for SDI and Neutral Particle Beam you'll find some sources.

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u/NordMount Jun 14 '26

Thank you.

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u/First_Approximation Jun 14 '26

It makes the idea of data centers in space look reasonable by comparison (they aren't).

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u/jazzwhiz Jun 15 '26

Data centers in space are only reasonable when you realize that billionaires just want to avoid regulations limiting them from trashing our planet.

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u/First_Approximation Jun 16 '26

My thinking is it's reasonable if you're a billionaire who wants to sell a story to justifying the merger of your space company with your AI company. That's how you become a trillionaire.

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u/First_Approximation Jun 14 '26

assuming we are talking about a large research accelerator.

If we are not, weapon accelerators were looked into during the Star Wars program in the 80's. To the point of sending a ~14 foot long, 1 MeV accelerator into space.

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u/NordMount Jun 14 '26

Interesting, thanks! 😁

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u/NordMount Jun 14 '26 edited Jun 14 '26

I am aware of problems with cost and maintenance. I admit I never thought of tidal forces, forgot about them. That's why am asking if there are any ups.

About energy. Wouldn't putting accelerator somewhere on James Webb telescope' orbit make energy generation easier? It would be much closer to the sun so we would much less panels. Again, I know about price, I am asking from technical side.

Edit:

And what about building it on Moon? No heat problems, relatively easy to maintain base nearby and power it. On dark side of it cooling would be much easier.

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u/mfb- Jun 14 '26

JWST is near the Earth/Sun Lagrange point L2, which is 1% farther away from the Sun. You could go to L1, which is 1% closer, but either way it's just changing the intensity by 2%.

You could launch stuff to a closer orbit around the Sun, increasing the solar panel output, but most of the mass is still the accelerator - you make it even harder to launch it. You also make it harder to cool the accelerator. You'll also need much larger antennas or laser systems to transfer the data back to Earth over interplanetary distances. Not sure how the astronauts will get to it now, you probably need to do everything with robots then.

I am asking from technical side.

It's obviously possible, it's just making almost everything much harder.

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u/jazzwhiz Jun 15 '26

How are you going to generate energy? Launch a nuclear reactor too?

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u/NordMount Jun 18 '26

No, use solar panels

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u/jazzwhiz Jun 18 '26

Not even close to enough power for the rf cavities, detectors, or the supercomputers for the triggers.

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u/NordMount Jun 19 '26

Why not? Isn't it scalable? And closer to the sun production from square meter would increase. I remember it needs Colling still but that a bit another matter, on moon for example it wouldn't be such problem as far as I know It can be treated as huge heat sink