I am building a space station that is supposed to last until the heat death of the universe. This space-station has access to practically an infinite amount of electricity, but since it has no active method of gathering materials from the outside it is built to reuse and recycle as many atoms as it can.

Assume current day technology. (Apart from the practically infinite electricity.)

Would it be possible to create a self repairing Whipple shield? One that can recycle all of the atoms hat have been hit by an impact.

I know that many research projects are studying the feasibility of a circular economy where all byproducts are used and reused, so that nothing would find its way onto landfills. Steel, for example, in our current economy is already almost endlessly reused. Many other products can already be reused if there was enough energy to do so.

Is there any material that can act like a Whipple-shield, and at the same time be kept close to the space-station so that is can be collected and reused after an impact?

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    $\begingroup$ "is supposed to last until heat death of the universe", "has access to an inifinite amount of energy", "reuse and recycle atoms". There are already many elements in your pemisce here that are not science-based, or at the very least definitely not assuming "current day technology". So, satisfying your requirements for an answer seems impossible. Also, the title and the body of the answer seem to be asking two related but different questions. $\endgroup$ Jul 13, 2022 at 5:19
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    $\begingroup$ If you have infinite power, why are you mucking about with low-tech solutions like whipple shields? Just build a massive laser array, and simply sweep space around you clean of everything. Also, "assuming present day technology" is clearly not going to work. We have problems making mechanisms that can last a thousand years or electrical things that last a hundred, what makes you think modern day technology can be made to last for trillions of years? $\endgroup$ Jul 13, 2022 at 12:05
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    $\begingroup$ @PostlimFort That is a wild claim to say ONLY [insert thing here] can do [insert action here]. $\endgroup$
    – Daron
    Jul 13, 2022 at 14:20
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    $\begingroup$ @BarbaudJulien Additionally, even just the concepts of "infinite energy" and the "heat death of the universe" are mutually incompatible. This is because at the heat death of the universe there will be no usable energy by definition. This ship will actively prevent the heat death of the universe by its existence. $\endgroup$
    – Mathaddict
    Jul 13, 2022 at 15:41
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    $\begingroup$ The very presence of this impossible vessel will make it impossible for the universe to achieve heat-death. If fact, its presence might very well be the catalyst for the universe to reboot itself after a while... $\endgroup$
    – Mermaker
    Jul 14, 2022 at 15:31

7 Answers 7


In an absolute sense, nothing is eternal, but given unlimited energy, we can get close. Your biggest enemy is going to be the preservation of angular momentum, where glancing blows will send bits flying. The next issue would be that, for an infinite time frame, collision with a larger body is inevitable.

When you say Whipple shield, the thing that comes to mind is a thin shell around a body that diffuses the worst of micrometeoroid impacts. The definition of micrometeoroid for this purpose is something smaller than the shield is thick. With that definition in mind, we can assume that something else (like a laser defense or capture strategy) exists to handle larger objects.

If you want it to last indefinitely, the shell has to be self-healing (as you specified). Imagine a framework (maybe geodesic) that supports a swarm of small robots. Not even nanobots, just hand-sized things that can re-organize themselves, distribute power, and lock into a semi-rigid, multi-layered structure.

  1. Maintain the shell configuration
  2. Catch slow-moving objects
  3. Stay in the way of fast-moving objects

You can also add things that allow you to go in and out of the space station, provide ports for observation platforms, etc.

The primary flaw in this is that it would be opaque. Maybe translucent, but definitely not transparent.

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    $\begingroup$ the fact that this answer is accepted because it is basically the only one that entertains the same idea as the question, although it is among the lowest-ranked, is a bit sad. the whole point of a whipple shield is to provide a shield that is more light-weight than its bulky counterpart (at the cost of being less durable), so that you have less payload to put in orbit. you have infinite energy to put stuff in orbit. A whipple shield is likely to be among the least pertinent solutions to your problem $\endgroup$ Jul 18, 2022 at 5:21
  • $\begingroup$ You feel that it's sad when the answer to a question is accepted because it actually answers the question asked? I'm curious what you think the goal of this process is. Creatively informing people that they're wrong, maybe? $\endgroup$ Jul 18, 2022 at 16:00

Add the space dust to your shield.

But it has no active method of gathering materials from the outside.

Au contraire mon frere! Your whole premise is to defend against materials you are gathering from the outside! If you have lemons, even tiny atom sized lemons moving at 0.8c, make lemonade!

Your shield is a self-healing vitreous viscoelastic polymer backed by a huge permanent magnet. Neither magnet nor shield requires energy to maintain. Nearly every tiny thing flying thru space carries a charge and when a charged particle enters the magnetic field it will produce its own magnetic field which slows and heats it. Such particles will gently settle down onto your polymer shield.

The shield will get dusty with time. It will grow. The polymer is accomodating of these additions. As time goes by the layer of dust and space materials grows into a crusty shell, speckled with pebbles and space cat hair. The look of it will connote great age and lack of maintenance which will be a good look for the graphic novel.

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    $\begingroup$ Eventually that "space station" is actually the heated core (thanks to its infinite electricity, of course) of a planet/moon, made entirely from all the debris is has collected. $\endgroup$
    – Michael W.
    Jul 13, 2022 at 23:39

Create new matter


That formula states that energy and mass are convertible from one into another.
With current technology, scientists have been able to convert matter into pure energy using matter & antimatter collision, thought at the micro-scale, of course.

So, if you have enough technology to create unlimited energy, doing the opposite process (creating matter and antimatter from energy) shouldn't be too difficult. The created anti-matter can simply be discarded.

Hawking radiation

You can inspire in black holes.
On the surface of a black hole, millions of tiny particles and anti-particles are created at the surface of the black hole and destroyed all the time. Sometimes, one of these particles in each pair manages to escape the black hole gravity. When that happens, the black hole loses mass in order to "pay" for the lost energy (1st law of thermodynamics).

Breit-Wheeler process

Another alternative (more realistic) is to create matter by colliding two high-energy photons, which decays into a pair of positron-electron particles.

[...] this experiment, the researchers were more interested in the near misses than the hits. Ultra-high-energy photons encircle the gold nuclei like an aura, and auras collide as nuclei zoom past one another. When photons (particles of light; massless, pure energy) collide, they generate an electron and a positron, its antimatter counterpart — both particles that have a mass. This is known as the Breit-Wheeler Process.


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    $\begingroup$ This is a nice answer, but it fails the "Assume current day technology" constraint, nonsensical as it is. $\endgroup$ Jul 13, 2022 at 13:51
  • $\begingroup$ @StarfishPrime, found a real-life form to create matter en.wikipedia.org/wiki/Breit%E2%80%93Wheeler_process. $\endgroup$
    – Ender Look
    Jul 13, 2022 at 13:55
  • $\begingroup$ worth noting that a positiron and elecron pair can be used to create matter, but it is very strange matter we have very little understanding of in the current day. See: en.wikipedia.org/wiki/Positronium That's a good thing! you can ascribe strange properties to these unusal forms of exotic matter. It can even form chemical bonds with regular matter such as en.wikipedia.org/wiki/Positronium_hydride $\endgroup$
    – Rugnir
    Jul 14, 2022 at 13:21
  • $\begingroup$ This is THE answer especially considering the premise of "infinite electricity" stated in the question. $\endgroup$
    – Luatic
    Jul 14, 2022 at 14:32

The loss of materials over time is a bit more of an issue than you might think. Iron is lost during steel production. Slag is skimmed off the surface to reduce impurities, but some iron is lost during this process. “Typically, during the slag skimming, more than half of the removed material is iron rather than slag.” (https://www.tandfonline.com/doi/full/10.1080/03019233.2020.1747778) No recycling process is 100% efficient, and material can/will be lost prior to recycling. A bridge truss will lose some of its steel through its conversion into rust, and the rust falling into the river below it. Losing 0.01% of your steel to corrosion each year might not matter when it can be replaced, but it adds up. The quality of recycled steel can degrade as contamination from other elements get mixed in. There is also the slag loss which occurs at the recycling stage as well when trying to remove said contamination. The biggest issue will be a loss of gases over time, as once they are gone there are no easy methods of recovering them. Someone opens an airlock and there goes the nitrogen/oxygen still in the room. As no pump can create a perfect vacuum, there will always be some loss. A single bad/failed seal can create an undetectable leak which slowly drain a station over decades/centuries. Something to think about.

As for your question, high speed impacts will cause debris to be ejected outward from the point of impact as energy is redirected, resulting in a loss of materials. Instead of a hard/strong self-repairing material, you could use gel capture. A shield made from gel a few meters thick which absorbs the materials that hits it. The energy from the impact is transmitted through the gel and the object stops at a certain point. This type of shield would degrade with time, so it would need to be recycled/replaced, but doing so would allow the station to recover the impact material trapped in the gel. You could hand wave the gel and make it a futuristic “smart memory gel” which grows over the hull of the station and reforms perfectly after impact. Heck, you could even have the gel move the material into a collection port. This would restore its original form and provide the station with the added mass from the impactor. The station becomes a sponge, absorbing material it encounters.


Frame challenge: There won't be a heat death of the universe.

If the space station "has access to an infinite amount of electricity", it can (easily!) prevent the heat death of the universe: simply heat everything up, or move everything around.

Assuming we will never be able to store infinite energy, does your source of infinite energy last an infinite amount of time? If no, then that's your real problem.

While your source lasts, you can easily create matter, or pull matter in from anywhere (the universe is not infinite, but it is a little bigger than most people's idea of a space station). In fact, you can pull in the very same atoms that you lose. Sure, you can't do it with current technology, but by the time that becomes a problem you will have had several millenia to advance your tech, with an infinite energy source.


Your assumptions are problematic because they are nowhere near science based nor attainable with current technology. To give you a taste of the god-like things you could do with infinite energy, here are a few things you could do to protect your station:

Destroy the universe

That sounds like a good place to start. Incinerate at least everything in range of "infinitely" powerful lasers all around you and push them away with radiation pressure. No need to worry about anything hitting you when there isn't anything left.

let me see that station move

We mentioned radiation pressure. Well, another slightly less radical use of infinitely powerful (and somehow ever lasting) lasers would be to use their recoil as means of propulsion. Constantly scan your surroundings with infinite-everlasting radars (damn this is convenient) and move out of the way when something crosses your path. Keeps your cardio going, too

don't recycle matter. Create it.

You are god, after all. If there's one equation that made it to the spotlights of pop science, it's $e=mc^2$ indeed. It's impossible to retain all the matter of a shield after an impact, but not to worry. Build enough particles accelerators, power them with your infinite juice. Convert that energy into matter. You'd need additional handwavium to explain how you turn the specific particles created into usable material, but honestly at this point it's nothing compared to what we are starting with. Heck, with infinite energy you could try exciting new things. It's really pretty unambitious to accelerate particles at this point. Let's try accelerating my mother-in-law and see what comes out of that?

it can't gather material from the outside?

Why not tho? Move from planets to asteroids and drill what you need in there. You're not running out of fuel any time soon. Again, how you turn that raw material into a shield seems like a minor detail compared to the rest. Just cram enough of it together to make a thick wall or something. Again, it's not like you really have any limiting factor on how much you can gather and do with it

I essentially mean to say that the assumptions are too over-the-top and unrealistic to ask for somewhat realistic answers. You need to dial it down way back before we can go for something believable. To be honest if you have infinite energy and you are focusing on making shields, I think you got your priorities wrong


Plasma fields.

With infinite energy You can cerate big electromagnets and hold fields of plasma in all directions. Plasma will gather all atoms wich be hited. This is only scale problem. And power. But You have infinite power. You can shield against neutron stars - need only bigger magnets. Can have problem with shielding against black holes but with actual knowledge shielding against them is not possible.

Main problem: magnets for shielding will be big and hot. So big that they can melt and collapse under thier gravity to point where You have no space-station only some kind of neutron star or even black hole

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    $\begingroup$ A plasma field? That sounds more like sci-fi linguo than a science-based proposition (scientifically I wouldn't know how to make sense of the words plasma and field together). Also, I think you'd better include a bit more details on how you expect to stop non-ferromagnetic debris with magnets. If what you meant was to create a big cloud of plasma, what matter is it that you plan to turn into plasma, and how do you intend to keep it from diffusing away? Also, how do you protect your own station from the cloud of plasma you plunged it into? $\endgroup$ Jul 13, 2022 at 8:55
  • $\begingroup$ @BarbaudJulien Being fair, the premise of this answer is already a couple orders of magnitude less absurd than the question itself. As a reader, this would be the last thing I would question. $\endgroup$
    – Mermaker
    Jul 14, 2022 at 15:34
  • $\begingroup$ In terms of universe-breaking implications, yes, nothing beats infinite energy . But I think that the idea of surrounding anything (let alone a high-techy stuff full of electronics) in plasma and calling it "protection" would be even more immediately absurd to me than an inifinite source of energy. $\endgroup$ Jul 15, 2022 at 5:35
  • $\begingroup$ Imagine donut shaped space station, 20 maybe 50 AU radius, with enough gravity to hold by gravity sun mas of plasma surrounding station like a bigger donut maybe even 1ly in size. Add coils to repel plasma from station and to make flow where plasma is going from outside to inside of space station circle, circulating around station. Yes You need 10^12 to 10^15 Gauses but with infinite energy... You can get materials from plasma flow to make repairs on station and dust joining Your shield wil rebuild it. $\endgroup$
    – Kamitergh
    Jul 15, 2022 at 9:39

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