My story opens with an old man who arrives at his "personal" asteroid somewhere out in space. When he arrives, everything is powered down and he has to bring systems online before he can take his suit off. He has left galactic society (perhaps there was a war) and he wants to live out his final days inside this rock. There is something in there he wants to see one last time. In years (or centuries) previous, he had significant resources to expend to hollow it out and create comfortable living space inside as well as a "workshop" for his pet project. Some sort of reactor (or collector) powers the whole thing, runs life support, etc.

Here are some ground rules of the story's universe:

  1. No FTL - All travel is sublight, though much faster than what we can do in the present day. Some time dilation occurs and hibernation allows people to survive trips potentially spanning centuries.

  2. No artificial gravity - Cylindrical colonies spin for centrifugal effect, but humanity has not figured out "gravitons" or whatever. We can fake it, but we can't make it.

  3. Detection technology - In the present day, we look at the skies with radio telescopes, optical telescopes, etc. In this future scenario, there hasn't been significant advance other than increased resolution and clarity applied to the same principles of physics we understand now. I'm sure there are other present-day technologies that I am unaware of. If any of these might affect this question, I'd hate to be ignorant of them

So the nut of my question is this:

How can he "hide" this asteroid, yet still be able to find it later?

Most likely, nobody would even be looking for it, but our protagonist is paranoid or at least careful. He would want it to not stand out too much from any other asteroids due to heat, unusual EM output, or any other odd behavior that could be noticed from great distances (if someone happened to be observing that part of the sky, potentially from any angle). As for locating it later, other than just eyeballing whatever region of space it's in once he gets there, I imagined there could be some sort of doohickey made of a material that only reflects EM waves of a specific obscure frequency. Shoot a blast of that frequency out into that general region and get a "ping" back once it hits the rock. Not sure how feasible that is though.

The following aspects of the asteroid (and/or his ship) are flexible as needed to satisfy the requirements of the question:

  1. Size of the asteroid - I don't know if it's the size of a house or the size of Texas, nor how this might affect not only its visibility, but its feasibility for hollowing out and inhabiting. Also, he doesn't have to use all the real estate. The inside could be the size of a house and the outside could be the size of Texas.

  2. Composition of the asteroid - Rock. Haha, but seriously, we assume he searched long enough/got lucky enough and found the "perfect" asteroid that can remain obscure, yet could be mined for at least some resources.

  3. Power source - Fusion? Fission? "Arc reactor" a la Iron Man? Some other magical McGuffin "future technology"? This might be the one place I'd have to apply some phlebotinum to make it work. Considerations would again include heat, EM waves, etc. that would affect how detectable it is.

  4. Propulsion - The asteroid itself might have a similar propulsion system to his ship though not geared toward interstellar travel. It would be used for simple maneuverability and attitude adjustments. But what it is and how it works is up in the air. See "Power source" above. Otherwise, simple rockets could work, or even something that expels gases if it only needs to be nudged slightly. Again, how it would affect detectability is a consideration.

  5. "Gravity" - Since we can't make gravity, the asteroid could spin for the aforementioned centrifuge effect. This might make docking his ship a bit more difficult unless he spins it up only after landing. But dependent on size, type of propulsion, power source, etc. it might be cost prohibitive to spin it up after landing, not to mention spinning it down upon his previous departure. And all that activity might make it more noticeable. I know the larger the rock, the more likely its own gravity would assert some force upon the man, but I imagine it would still be trivial. From the get-go I've been leaning toward magnetic boots. Staying in a non-spinning asteroid for long periods would likely lead to the usual microgravity symptoms such as atrophy, osteoporosis, etc. But he plans on dying here in peace, so this is not as much of a consideration.

  6. Proximity to other heavenly bodies - Would it be better if the asteroid were near enough to a star to glean some energy from it? Would this make it more noticeable or less? Would it be better to orbit a planet which is itself in orbit around such a star? Or would it be better to be somewhere in the deep, away from the other cosmic "big boys"? Would being off in a relatively "dark" area of space make it more noticeable or less? This is assuming its power source can keep it warm enough inside to sustain a human life for possibly years.

Hopefully this is enough conditions (and not too many!) to help fill in any of my gaps in logic. I appreciate everyone's time and thoughts. Thanks!

Edit to address possible duplicate:

This is not a duplicate of the "stealth in space" question, as that seems to be geared toward an active cat-and-mouse type scenario involving a moving ship that is travelling hither and yon, trying to outsmart space pirates who also travel hither and yon.

In the case of the old man and the asteroid, the rock doesn't need much maneuverability nor sensor capability. EM and heat emissions would be shielded as much as possible and the whole thing wouldn't be going anywhere other than its existing orbital path.

Additionally, one of the requirements was that it could not hide behind or in front of things. No such restriction applies to my question. In fact, the allowance for hiding among other asteroids lent itself to part of the accepted answer.

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    $\begingroup$ You can't hide the thermal signature. Keeping it warm enough on the inside is going to make it warm on the outside. Viewed in the right spectrum, it will shine. Same for the ship heading there. With current technology we can see an idle Space Shuttle with life support going if it was orbiting Saturn. It's heat signature is unmistakable. The temperature above background makes it easy. The best way to hide is it this way is to create a hole in whatever sensor nets normally look in the right wavelengths. A random ship might scan there, but thats the risk. $\endgroup$ Jun 23, 2016 at 18:27
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    $\begingroup$ Possible duplicate of Stealth in Space: How realistic is it? $\endgroup$
    – JDługosz
    Jun 23, 2016 at 23:20
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    $\begingroup$ Slight nit-pick: using a rotating space station isn't "faking" gravity - it's exactly the same as the force of gravity. The equivalence principle states that the force felt due to being in an accelerating reference frame is no different than the force felt due to being in a gravitational field. $\endgroup$
    – user14624
    Jun 24, 2016 at 7:32
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    $\begingroup$ Centrifugal forces are not equivalent to gravity. For one thing, movement opposite the rotation inducing the centripidal acceleration reduces the force applied. Gravity acts on a mass as a field effect while CF acts only through the contact surfaces that provide the acceleration. (can include drag) When using certain simpifications, they look quite similar, but really aren't. The term for that is "equipolent". $\endgroup$
    – The Nate
    Jun 24, 2016 at 17:45
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    $\begingroup$ @mego The principle of equivalence doesn't state the complete equivalence between acceleration of a frame of reference and gravity: it states that if a frame of reference is uniformly accelerated (an that excludes rotations) the effect is locally indistinguishable from gravity. The effect of any rotating frame of reference would be distinguishable from gravity by other effects, e.g. the Coriolis effect. $\endgroup$ Jun 25, 2016 at 10:54

20 Answers 20


The primary way to hide something in space is to make it uninteresting. Start with a boring asteroid, made out of silicate rock rather than metals or organic compounds that are worth mining, orbiting somewhere that's inconvenient to reach, but not so inconvenient that people will go there for the achievement.

In Earth's solar system, this would be a main-belt asteroid, fairly small (perhaps 500 metres long) with a fairly large orbital inclination, so that it needs a lot of fuel to reach.

Don't put anything interesting or artificial on its surface. Power down its systems completely, so that it's at the same temperature as any other rock. Record its orbit really, really carefully, and make sure you know about all the other objects in the system. With that and a decent navigation program, you can reliably find it again any time in the next few thousand years, which sounds long enough. This gives you the best odds of nobody deciding to look at it or interfere with it. Doing anything active to hide it makes it more interesting.

How do you keep from being noticed while hollowing it out and equipping it? Do that before anyone else is taking any interest in asteroids in this star system. So you want to have been a scout in the past, visiting previously unexplored systems, and setting up hidden bases for yourself in several of them. That implies a fair amount about the scouting system in your interstellar society - can you make that work?

How do you keep from being noticed once you've moved in? Keep your emissions of all kinds to a minimum. Generate as little power and heat as possible, don't use radio, hide your ship in the underground hangar.

On your points:

  1. Size: small, so it's uninteresting.
  2. Composition: very boring.
  3. Power: fission is fine, but you need to run it at as low a level as possible.
  4. Propulsion: Don't, it risks making the asteroid interesting.
  5. Gravity: Spin it up when you build the base and leave it that way. All asteroids spin anyway. Making it spin fast enough for 1G would make it interesting, so settle for less.
  6. Location: In a star system, in an asteroid belt. Finding and reaching loose asteroids is hard, and they get very cold. In the star system, it will stay at least somewhat warm, which is easier on the equipment you've installed.
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    $\begingroup$ Rather than spinning the asteroid, could you instead build two counter-rotating centrifuges inside it? That way you get whatever gravity you want, but don't have to worry about exterior rotation attracting interest. $\endgroup$
    – Deolater
    Jun 23, 2016 at 17:45
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    $\begingroup$ I'm not sure we have everyday size references in common. 500 meters is much bigger than your house, but we don't have shopping malls in standard sizes over here. Say it's 500 x 300 x 200 metres, shaped like a somewhat diseased potato, which is very normal for asteroids. It has a volume of maybe 20 million cubic metres, and would weight about 80 million tons. There's space for a large mansion house inside it, with plenty of wall thickness left. $\endgroup$ Jun 23, 2016 at 18:51
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    $\begingroup$ If you want more power, pick an asteroid close-ish to its star. If you carefully reflect away an amount of incoming radiation equal in energy to the heat you produce, your asteroid will appear 'normal', heat-wise, for an asteroid in its location. $\endgroup$
    – ckersch
    Jun 23, 2016 at 21:35
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    $\begingroup$ "but not so inconvenient that people will go there for the achievement." Heh. $\endgroup$ Jun 24, 2016 at 1:21
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    $\begingroup$ @Falco My suggestion was based on vague intuition, I don't really want to try to work out what would actually happen. I proposed a pair of counter-rotating centrifuges to have no net rotation force on the asteroid. I suppose other gyroscopic effects could be important, I don't know. It would certainly help if the gyroscope mass was very small relative to the size of the asteroid. $\endgroup$
    – Deolater
    Jun 24, 2016 at 14:08

Space is big. Really big. Looking for a particular asteroid somewhere in the solar system is pretty analogous to looking for a particular rock, somewhere on Earth. Unless you already have a really good idea where to look, you're not going to find it.

As such, I would suggest that he doesn't need to take any measures to hide it, just place it out of the way of anything people are likely to visit. Consider the fact that we're still finding new near-Earth asteroids in the inner solar system (even when we're looking, it's hard to see something that doesn't reflect or generate light), and haven't even begun to map the Oort cloud.

In a future with private spaceflight, I'd expect there to be asteroid mining activities, and outposts or colonies near habitable planets, and therefore, I'd suggest that the best option would be finding a suitable asteroid out in the Oort cloud, or dragging something into orbit way out in the far reaches of the solar system. An asteroid in our solar system's asteroid belt (for example) or otherwise near colonies or outposts could possibly be stumbled onto by mining activities, and I don't think a paranoid person would take that risk. On the other hand, place it way out on the edge of the system where no one goes, and you reduce the chances of someone stumbling on it to about 0. Putting it near the Oort cloud provides the advantages of both isolation and camouflage - not only is it somewhere no one's going to bother to travel to, it's also surrounded by billions of other similar objects, so no one will be able to pick it out, even if they did end up in the area, somewhow.

As long as you know its orbital path and speed, you'll know where it's going to be, and when, which would allow you to make your way back to it.

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    $\begingroup$ But those asteroids are very, very cold. Anything with a human-habitable environment is going to stick out like a sore thumb on any thermal imaging - and we use IR to scan the solar system all the time. It's like trying to find a marble in a heap of marbles... with the target marble shining a bright light. $\endgroup$
    – Luaan
    Jun 27, 2016 at 8:44
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    $\begingroup$ @Luaan To a large extent, there just isn't any stealth in space, but between thermal insulation/shielding, other Oort Cloud objects between the asteroid and any telescopes, being out of the way, and not being powered when the protagonist isn't there, it could probably be pretty hidden. And that's as good as you're going to be able to do. $\endgroup$ Jun 27, 2016 at 14:10
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    $\begingroup$ Thermal insulation doesn't really help - you still need to radiate all your excess heat to space and even just a single human produces quite a large amount of heat, even ignoring the necessary life support equipment. Oort cloud will help, but do note that the reason it's so hard to see anything there isn't just the size of the (expected) objects there - it's that they're the same temperature as the background. And it will be very suspicious when you need to travel there - which needs an impulse to match velocities, which would be very visible even this far out. $\endgroup$
    – Luaan
    Jun 27, 2016 at 14:51
  • $\begingroup$ The problem with the Oort cloud (or, for that matter, interstellar space) is the lack of FTL. If this old man is okay with traveling a year or more to reach the hideout, it works. That's a pretty big if, though. $\endgroup$
    – Jasper
    Jun 27, 2016 at 16:52
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    $\begingroup$ @Luaan: Then build your house inside a medium sized planetoid, something with that much mass will soak up the heat of one person and radiate it space, and it's so little compared to it's mass that it will never be noticed. $\endgroup$ Dec 1, 2017 at 11:41

Where do you hide a tree? In a forest.

An asteroid? In an asteroid belt, obviously... Just find any asteroid belt that seems far away and already explored, perhaps in an old galactic area, and stick it in there.

As for finding it? If he knows what asteroid belt it's in, he can calculate orbits and have the computer figure out where it is later when he gets back to it.

Alternatively,use a giant space RFID tag.


There must be something pretty special that exists only inside this asteroid.

Select an asteroid of sufficient size to burrow into the middle, but not so large as to make mining exploration appealing. Build a mini-capsule inside that spins independently of the asteroid. There's your full gravity, independent of the asteroid's rotation.

With a sufficiently large crust, any heat from the flubberconverter coils could be absorbed and diffused into the asteroid itself without raising ambient temperatures to externally interesting levels. Avoid localized heat build up by drilling a network of negative space from the inside and build a massive distributed heat-sink.

If it's a big enough asteroid, inside the capsule/mini-ship he can create a self-balancing ecosystem for himself, given enough self-discipline not to overtax its boundaries. For example, he can live there comfortably without overeating his oxygen-producing crops, but a visitor would destroy the balance and doom the life-support within days. Or he can only pirate the galactic news feed for an hour a day without stealing power from his plant's lighting, etc. Maybe his imported sea-bass get very ill-tempered if he doesn't eat enough of them, which may be likely if he gets tired of writing his cookbook, '101 Ingenious Ways to Eat the Same Thing for the Rest of Your Life'.

The major detection problems would be in going and coming, unless it was in a dangerous part of space (what isn't?) where it would be more conceivable for ships to drop off of long range scanners without notice. Even inconvenient portions of the galaxy will have occasional visitors. Perhaps he will turn on the lights, and never leave again - that has its own ramifications.

As others have stated, the best camouflage is to look as natural and normal and boring as possible. There may be an opportunity here to line the inner portion of the asteroid with heavier metals to give the illusion of a solid mass to casual scans, much in the same way that lead is sometimes used to fake a "solid" gold bar.

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    $\begingroup$ I love the heatsink idea! He is not expecting any visitors. Indeed, he wants none. $\endgroup$
    – dolst
    Jun 23, 2016 at 18:47
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    $\begingroup$ Lead is not heavier than gold. It's simply the heaviest cheap metal. $\endgroup$
    – Random832
    Jun 24, 2016 at 2:10
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    $\begingroup$ @Random832 2 pounds of lead is heavier than 1 pound of gold ;) $\endgroup$
    – Beofett
    Jun 24, 2016 at 19:54

Pick a nondescript star within a hundred light years and make a pulsar map (like the one we sent with the Pioneer space probes).

Now you need to be in the right solar system.

Grab an asteroid and throw it into a highly elliptical solar orbit that throws it out into deep space for 100-10000 years or more at a time, coming back into the inner system for a few months/years before being slung back out.

Now you need to either get lucky (very low chance at random) or know when it'll be 'near' the star. Essentially an artificial or hollowed out long period comet. If you pick one that doesn't get close enough/composed of the right materials to generate a visible tail and small enough, no one will bother even if they are around to detect it.

Less sneaky than just putting it in the OORT cloud, but it makes it easier to find.

Have it listening for a wakeup radio burst with his personal code: restarts the reactor and turns on a beacon, then he can lock onto it and rendezvous. A listening antenna will be essentially unnoticeable and the electronics to monitor it will take very little power and give off very little heat... couple it with heat activation from entering the inner solar system and it will be a dead rock when out in space, only listening when it gets near the star.


He not need to "hide" his asteroid, he just need to know its orbit. As stated in another answer to a different question, in space you are always orbiting something.

If the asteroid has no structure on the surface, it is indistinguishable from the other millions out there, so he just need to choose one of the many present in the asteroid belt and just keep track of it and fit out how he like.

As a personal choice, I'd go for an asteroid on the far end of the asteroid belt, about some thousand meters in diameter (or event somewhat bigger). This position make it relatively uninteresting, since also wanting to mine it, you probably go for an asteroid in the near end of the belt, just for simplicity.

Hollowing the inside, you can probably get a space of some tens of thousand cubic meters, and spare way more volume as reserve and for mining. A good power source can be a well shielded fusion reactor, and eventually, a solar array as a backup, but they are vulnerable to micro impact and they are very visible.

The tricky point is the gravity, since you need to make the asteroid spin at the right speed, which can be not so easy to set up and depend on the diameter of the internal habitat. I'd not set up a propulsion system, since I see it as useless on an asteroid and there is the risk to make it somewhat more interesting of the other millions.


While previous answers have covered where and how to hide the asteroid, they didn't mention the details required to relocate the asteroid once you need to return to it.

While orbits in large solar systems are unlikely to change over time, especially in uninteresting areas, it is likely that someone as paranoid as described would be happy with merely that in an age of private spaceflight. Perhaps some other reclusive multi-millionaire wants to redirect a couple of asteroids for his pet park project, or for his space megastructure. In these cases, the orbits may be perturbed, and unless he has a telescope to track the asteroid on a local planet, he is going to lose his well-hidden habitat.

A good way to counter this is to install a passive RF array on the asteroid, hidden below a few meters of rock so as to resist micrometeorite impacts but yet not suffer too much signal attenuation.

This passive array would listen on the "activating signal" channel, maintaining perfect radio silence. Only if the correct handshake with key is sent will the passive array activate. Using a phased array, a directional beam can be sent to the location of the ship. The power of the transmission will be tuned to the distance of the ship (by measuring the received signal power) and therefore will be essentially undetectable at a distance due to noise.

This system would greatly decrease the likelihood of losing the investment on the habitat, yet not significantly increase the risks of it being found by others.

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    $\begingroup$ I think this is already referenced in @Aify's answer, basically an RFID tag in space. $\endgroup$
    – Martheen
    Jun 24, 2016 at 2:03
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    $\begingroup$ @Martheen An RFID tag has far inferior range to a targeted radio scan, and would likely leak more information than necessary. The aim is to be as precise as possible with your signals, to avoid being detected by scanners. $\endgroup$
    – March Ho
    Jun 24, 2016 at 2:10
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    $\begingroup$ Of course we won't literally put a gigantic RFID that answer to standar Space-RFID protocol. The actual implementation will be just like in your answer, I just point out that someone already mention a passive detection system instead of merely remembering orbit $\endgroup$
    – Martheen
    Jun 24, 2016 at 2:13
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    $\begingroup$ Well, I gotta give kudos for the detailed explanation of such a system. Thanks! $\endgroup$
    – dolst
    Jun 24, 2016 at 14:16

The other answers have already covered how to select the asteroid, so I'm going to focus on two points: power & spin.

If you have some internal structure suspended on low-friction bearings (magnetic bearings if they wouldn't result in a detectable anomaly; my E&M-fu is too weak to say), it could spin at whatever rate necessary independent of the asteroid's own spin. You'd just need to compensate for friction losses, which leads to the second point: power.

Anything you do will result in waste heat; this includes both generating & consuming power. On both fronts, you'll be less noticeable with higher efficiency & lower power requirements. Passive power sources could drive your heat signature down even further. Possibilities include thermoelectric harvesting or Stirling engines (both exploiting temperature differential between sun & dark sides) and piezoelectric tidal power (if the asteroid's axis of rotation is parallelish to its orbital axis and it's rotation rate is in sync with the natural frequency of the mode which is excited by the tidal forces).

  • $\begingroup$ I have to admit, there is something appealing about having a Stirling engine on this rock! $\endgroup$
    – dolst
    Jun 23, 2016 at 18:49
  • $\begingroup$ I think a passive or weakly active magnetic bearing system can be EM-hidden within a rocky asteroid if you use the right materials. Line the inside with something electrically conductive and highly magnetically permeable and the field lines will stay almost entirely within the asteroid. I think. $\endgroup$ Jun 23, 2016 at 21:04
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    $\begingroup$ Magnetic bearings would not be detectable from outside the asteroid and iron containing asteroids are magnetic anyway. $\endgroup$ Jun 23, 2016 at 21:40
  • $\begingroup$ Spinning up your internal structure makes the asteroid spin the other way. $\endgroup$
    – user253751
    Mar 6, 2020 at 11:52

Asteroids with Volcanic activity

According to research by Professor Lionel Wilson as described in this article, there are asteroids with volcanic activity that much resembles the volcanic activity on earth. This means that your asteroid base could use geothermal energy as the only necessary source of power. This base could also be located by a volcanic hot spot on the asteroids surface in order to further disguise any escaping heat from your base. I am not quite sure exactly how common there asteroids are, and if they are rare or valuable enough to be significant sources of interest.

In addition, it may be that bodies with sufficiently large metal cores could, through a geodynamo, generate a protective magnetic field, assisting in disguising any escaping signals and protecting your base from high energy particles, solar wind, etc.

As for your requirements:

  1. Size of the asteroid - I assume that any asteroid large enough to have volcanic activity would also be large enough to serve as a base. Any concern would likely lie in the other direction, with concerns over size and conspicuousness.

  2. Composition of the asteroid - This asteroid would likely have plenty of resources, as it is larger and has sufficient metallic content to form a metallic, molten core. Again, concerns would be with standing out and being too attractive. However, in a civilization with a galactic economy, it would likely be an extremely long time before an attempt was made to exploit an asteroid that is far enough off the beaten path.

  3. Power source - Solved above. Would definitely require a certain level of sophistication in technology and heavy equipment.

  4. Propulsion - In a civilization with the ability to travel through space, there would almost certainly have to be very detailed maps, including current and future location, velocity, and direction. Any significant change in predicted pathing would likely be discovered extremely quickly, unless the asteroid is in a location that is rarely "scanned" or hidden. Again, if you pursue a scenario where the asteroid is extremely small and far away from inhabited and traveled locations, you could get away with it.

  5. "Gravity" - Asteroids large enough to have volcanic activity are not necessarily large enough to have sufficient gravity to live comfortably. 4 Vesta, the asteroid named in the aforementioned article, only has a gravity of 0.025g, or 2.5% of earth's gravity. I would approach solving this by having the base located below the surface of the asteroid, with a spinning living space or large spinning space with the axis anchored to the asteroid's rock.

  6. Proximity to other heavenly bodies - As these asteroids are fairly noteworthy, one would likely have to chose a one orbiting a star far away from population centers, depending on the proclivities of the civilization with relation to mining and exploring asteroids. An asteroid floating in the cold of space would likely radiate heat until it cools, but that process would likely take millions of years.

Vesta, the Asteroid with signs of Volcanic activity

Vesta, the Asteroid with signs of Volcanic activity

  • $\begingroup$ Where does the Wikipedia article mention asteroids, or Professor Lionel Wilson? $\endgroup$ Jun 26, 2016 at 3:07
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    $\begingroup$ @AntonSherwood As this is my first post, I only got two links, something I didn't account for in the writing of this answer, which sorta botched the linking. I fixed it and and added back in the proper links. $\endgroup$
    – Dent7777
    Jun 27, 2016 at 13:30

There are some flaws in logic, but nothing super stretching


You can't spin asteroid fast enough to keep 1g gravity. Reasons for that are simple:

  • First of all mass of asteroid, composition of asteroid, own gravity

Asteroid are not object with exclusive strength, and as you wish 1g be inside of asteroid, and gravity of asteroid is less then 1g, everything, not glued to surfaces will fly away, and that will be probably 100% of asteroid, in most cases. Asteroid objects keeping structure integrity in that case will be very suspicious. I'll even not bother to list other reasons.

Good thing, you do not have to - just rotate living volume. Also that will free you from other technical difficulties connected with rotating asteroid.

That applies some limitation on minimum size of such asteroid, how much Coriolis effect you will have. 10km size asteroids are ok.


depends more on social aspects, then technical-detection stuff.

If he wish to look on system star at evenings - just enough to choose system without humans. We barely see planets, in near by systems, and it's not because we bad at that, there are some fundamental physical limitations, let say gravity, length of electromagnetic waves, thermonuclear reactions in stars - that everything will stay. And he knows current limitations is possible to predict dark spots. For us now it's any star system, will not stay long, but +100 Ly probably is fine, for next 200y.

If system without humans is not an option - then he have to exploit social ways to hide his asteroid. Let say officially owning it, but pretending to be something other, let say pirate group all fear to mess with, pretend to be their base - even if such group does not exists in reality, and lives entirely in rumors of people. Source of bad wudu magic here etc etc. Any sort of social disguise will work.

If he ok with no star system, I may recommend to take free floating planet.

Even in case mass and cheap sub 1c travels - most routes will be between stars. You may draw lines from each star to each star - route map.

But beside these routes most part of space will be at 0 attendance. But being in right time in right place, there is a chance being on such routes to spot traveling planet (or any body actually), and there will be chance that next such possibility will be undefined time. Trajectory not close to any possible route.

It will be not easy to make some base there, because it flies away from routes. It will be big expense to get on that planet next time. And use that opportunity at all - but that hard reach and more time it flies away, bigger expense will it be to get there.

  • it may depend on nature of space travel, but with most hard suggestions it's true. But even if it's not case - you have to know that that particular point in space and time is somehow interesting.

With big planet body, or moon like, or big asteroid like - there is't much concern about hiding heat sources. Depending on size of that body, if you somewhere deep - it will take 10000+ years to your heat (megawatts gigawatts will change surface temperature on small part of K - just take heat capacity of body and calculate)

Nothing is perfect

Nothing is perfect and you have deal with that. If he found and so may and others.

But nothing special actually, as result.

  • Deep space, far from routes, big body
  • far from humans, star system, any body
  • system with humans, own trough shell company.

Energy sources any in all 3 cases, waste have to be below star energy.

Hm but if it will above star energy and be not star(any kind) - I'll knock first, to check if someone home and wish have guests. If not, I'll fly away. Nothing worth so much troubles, I mean, nothing I may gain at the moment from that situation, worth of troubles, most valuable information about existing such phenomena already taken.
Probably not your case scenario, but.

Just flying away is also not bad scenario, just take big ship (buy, steal) fly in no return and undefined direction.


Hide asteroid in gas giant.

  1. Hollow out asteroid and fill with old man suitable atmosphere and old man suitable pressure.

  2. Allow asteroid to fall into gas giant. Like a metal ball falling into water, the asteroid will fall down into an area where the atmosphere is pressurized to a point that the gas-filled asteroid is buoyant. The asteroid will then travel back up, and down until it rests at the level in the atmosphere where it is neutrally buoyant.

  3. Asteroid drifts around deep in the gas giant. It cannot be seen from space. It emits signals similar enough to ambient radiofrequency and electrical signals coming from this planet that only someone studying these random signals would realize some were nonrandom. These signals are so the asteroid can be located.

  4. Asteroid could be propelled by sails.

  5. Asteroid could be powered by windmills.

  6. It is nice inside the asteroid. There is gravity, from the gas giant. It is a smallish Neptune-like gas giant so gravity is not too much. Old man stays buff.


An answer has been selected, but maybe some new ideas are still helpful.


There are likely a vast multitude of rogue planets in interstellar space, enough that maybe no one's looking too hard at any single one: they are much farther apart than asteroids are, after all. A small moon of a rogue gas giant would be great if he doesn't mind the long trip.


The moon should be icy. Such bodies are utterly unremarkable around a gas giant. Ices make a fine long-term fuel source for a fusion plant.

A "singularity plant" is another possible power source. Get yourself a microsingularity. Make it a charged one so you can suspend it in an electric field. Give it a lot of charge because it will mass something like a trillion kilograms (so maybe it needs to be generated on site). (I think you don't want it to have a magnetic field, but I'm not sure. I think it won't have a magnetic field unless it's spinning, but I'm not sure about that either.) At the right mass, it puts out Hawking radiation at a useful rate. It will evaporate, so feed it matter to keep it at the right mass. Bam. Matter to energy conversion. I'm pretty sure it puts out X-rays, so you shield it with something like lead. Pure lead is no good because of its low melting point. The hot shield gives you the temperature gradient you need for power.

Singularity plants are probably stable. In a gigawatt plant, the singularity will take trillions of years to evaporate. If containment is lost, the greatest threat will be an electric arc as it equalizes its charge with the environment. It won't be able to gather mass quickly enough to be a real gravitational threat anytime soon. It'll bore a microscopic hole through the floor as it falls, though.


Tidal forces could explain a higher-than-ambient temperature at first glance. It could expel heat with artificial geysers. Particle beams might also work, but he would need to take special care to avoid making hot spots on the surface. Dumb proximity detectors could insure the beam doesn't hit anything.

Special materials can store a lot of waste energy -- bombard some isotope with waste alpha particles so it transmutes, or use something that undergoes chemical changes instead of phase changes. The thing is (although I don't have time to think about it much), I believe you can't store all of your waste energy cleanly. I think heat must leak from the system in every storage-release cycle because entropy has to increase each time. You should be able to do better than dumb heat sinking though.

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    $\begingroup$ I do like the alternative possibility of placing it on a moon instead of an asteroid. Not sure I'll go that route, but I like it! $\endgroup$
    – dolst
    Jun 24, 2016 at 14:14

Rather than the most undesirable rock with absolutely nothing artificial showing on the surface, you could pick one that has already been thoroughly mined; such a history (which you might be able to fake!) accounts for the presence of ‘abandoned’ equipment.


Many good answers here, so this will be a bit redundant in places.

You don't need to actually hide it, you just need to make it totally uninteresting. Hide it in plain sight. As one poster said, make it a derelict mined-out asteroid. Strip it down completely, so it is completely uninteresting. Since it WAS a working asteroid, it would be expected to have a locator beacon. Nothing attractive about that. It could even still be used as a navigation beacon.

Any heat signature would be put down to previous activity. Things take a long time to cool down in space.

Actually, spinning the asteroid to provide gravity would make it even more unattractive to exploration. A spinning asteroid is quite difficult to land on, except for the poles. If the spinning were put down to an industrial accident on the original mining operation, which made it untenable, even less likely anyone would visit. A catastrophic accident would make the asteroid jinxed. Just a bad place to be.

As one poster said, put radioactive refuse at the poles, which are the only viable landing spots. No one wants to land in a radioactive refuse dump. Leftovers from the catastrophic event that caused the decommissioning of the mining operation. A hardened ship could make it past the radioactivity, through a camouflaged tunnel, and the buried living quarters would be shielded by the mass of the asteroid.

If anyone DOES become attracted to the asteroid, I am sure they would not stay around long enough to explore it. They certainly would not go anywhere near the radioactive entrance.

The idea is to project the message 'Nothing of interest here, folks. Just move along. Much more interesting things over there.'

There are many examples on earth of abandoned facilities remaining completely uninvited and uninteresting.

Since you are the author of the story, everyone in the universe does and thinks exactly the way you want them to. If you don't want anyone to be curious, they aren't. Just give a sufficiently believable reason for them to reasonably NOT be curious.

  • $\begingroup$ This should be the answer, the only way to hide something in space is to let things show but give them a known reason for it not to be interesting. $\endgroup$
    – John
    Dec 20, 2019 at 14:43

I would chop it up into tiny pieces, like a giant puzzle. That would make it not an astroid really, but a rock field.

For one, radar wouldn't be able to detect it if the pieces were small enough and far apart, and radio waves are quite large. Secondly, no one's really interested or would suspect they fit back together. Third, maybe it's impossible to put back together unless you know the trick, so even if you found it, captured it, it's worthless because you don't know the "password" to unlock the rock.

You can figure out how to put them back together. Maybe it requires a little nudge and it all falls into place over the course of a year, maybe your drones have to assemble them for you.


Perhaps put the asteroid inside of a nebula of a certain temperature? With a large enough nebula at the proper temperature I believe that it should be impossible to see the asteroid inside of the nebula via Astronomical Spectroscopy (https://en.wikipedia.org/wiki/Astronomical_spectroscopy) or any other form of detection. It's been a while since my high school Astronomy class however if I'm remembering correctly this should be feasible.


The big problem is heat as a by-product of energy usage. Three possibilities:

  1. Place it somewhere hot, where its radiation is lost in the background

  2. Collect the waste heat (and by doing so generate more waste heat) and somehow dispose of it - seems to me it might be possible to radiate it away in directions and intensities not likely to be "interesting"

  3. locate the asteroid way far out of any star system (in the interstellar medium) and away from paths from here to there and give it sufficient velocity such that nothing is likely to catch up with it. As far as finding it, since centuries might go by before he decides to find it, the only way I can think of is a beacon which responds to a code with signal of a known but apparently random noise pattern. Oh, did I say it should be out of the ecliptic? that's pretty obvious, right? You do know that we can't see (naked eye) 20 of the nearest 30 stars, right? It's pretty easy to calculate a reasonable limit for future sensitivity and then figure out how far away an asteroid (small is better) would need to be to be below that limit of emission. As far as spin for gravity, since the little g* will equal r (2π/T)² and if the outer 'floor' is 9.8 m in diameter, spinning the rock once per second gives 1g. I think smaller will be easier (although if seen more 'interesting') to spin up. You haven't explained how he gets the work done preparing it, without leaving all sorts of clues and traces and emissions...

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    $\begingroup$ Please add paragraphs! $\endgroup$
    – JDługosz
    Jun 23, 2016 at 23:22
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    $\begingroup$ If it were out of the ecliptic, it's likely that there it is going to be more interesting than normal, since very few asteroids orbit significantly out of the ecliptic. $\endgroup$
    – March Ho
    Jun 24, 2016 at 1:54
  • $\begingroup$ @MarchHo - relatively few in terms of overall proportion, but still quite a lot -- there are believed to be in excess of 10,000 scattered belt objects with diameters > 100km, for instance, which are mostly distributed between 30 and 40 degrees inclination from the ecliptic -- and given that it would be much more expensive to visit a non-ecliptic-orbiting asteroid, it is unlikely anyone would attempt to do so unless there were a good reason for it. We may want to visit Eris some day, perhaps (44 degrees from the ecliptic, 2,200km diameter) but smaller objects don't seem interesting enough. $\endgroup$
    – Jules
    Jun 25, 2016 at 13:40

Have your asteriod *outside of galactic society*

As you said in the question, this man has left "galactic society". Let's say he goes to the nearest galaxy.

The nearest galaxy to Earth is about 2.5 million light years away.

Old man Jenkins can't travel at the speed of light, so it takes him more than 2.5 million years to get there (but because of time-dilation and additional handwaving, let's say that to him it only feels like 2.5 million years).

After travel in a specific direction for such a long time, chances are both Jenkins and his asteroid will be very difficult to find.

The only problem remaining is that, due to less-than-FTL travel, Jenkins is ~2.5 million years old, so I'm not sure how many days he has left to enjoy his asteroid.

TL;DR—just go in one direction for long enough, and it's hard for someone to track you down. But the real problem here is not having FTL.

  • $\begingroup$ Note that you don't need to worry about sonars/detectors, because without FTL it takes them more than (2.5 million years)x2 (there and back again) to receive the signal that you're at the asteroid. $\endgroup$
    – Mirror318
    Jun 26, 2016 at 23:53

Interesting answers here, but personally the one I would go with would be:

Hide in plain sight

Your pal probably isn't the only space cowboy looking to hollow out a bit of asteroid for their own private purposes. Chances are there will probably be privately owned asteroid belts that rent out rocks, fewer questions the better. Payments are made via untraceable crypto-currencies, and the owner prefers not knowing the clients, and vice versa. They might even use the rents to employ enough mercenaries to keep their property safe from intruders. Such proprietors would likely have a distrust in government, and might not even live in the same solar system, so there won't be anybody to sell you out.

Here are some advantages to this model compared to the "hide in a rock in an uninhabited solar system far away" approach that seems to be broadly favored here:

Plausible Deniability

There's no way you're gonna get to your asteroid and back completely undetected. In fact, the more off-the-beaten path you appear to be flying, and the more your ship seems destined to reach that point, the more suspicious it looks. But if you're just one more ship around the Interstellar-U-Store-It, nobody will notice. It could be perfectly common for owned asteroids to use semi-artificial gravity, so you won't need to be floating around the whole time or hoping that your 1G spin doesn't attract any undue attention.

Fresh Supplies

How long till you get sick of toothpaste meals? If there are dozens or hundreds or even thousands of other asteroid-renters in the belt, there will likely be new supplies of all sorts coming in daily. Might not be the highest quality or fastest delivery you'd get living on some fancy-schmancy metropolitan planet, but this way you could have the things you need delivered to you, just another address among many, not raising any questions.


Someone comes poking around and the hired mercenaries will at first very politely ask them to leave, but can be there to fight on your behalf. Whereas if you're on your own and the wrong people knock on your door, their disappearance from a remote and inconspicuous corner of space will look very conspicuous indeed.


This goes hand-in-hand with security and supplies. If you ever need to leave, you can just put on a space suit and take the next shuttle out and nobody will notice you in particular. Likewise, if you want to return, you will just be one body among many.


Even if you are so well-supplied that you need none of the things listed above, eventually, there might be a need to leave. There could be a medical problem that neither you nor your robots could help you with. You might need high quality fuel or precision equipment to repair a component that was knocked awry by an errant meteorite, and without it, you might not survive an interstellar journey to get what you need.


We all get a little lonely, sometimes.


A real cloaking experiment is mentioned here. An object coated with this material actually absorbs EM at given frequencies (In this example visible light) redirects it and sends it out on the other side, so the light appears to go through it. The material is not perfect, but in the near future it may be. Drawback: To work perfectly on visible light, it must prevent any light reaching the object's surface, so it will bask in perpetual darkness, and drawing solar energy will be impossible. It may be fine-tuned to reflect a wide EM spectrum this way, but it does not prevent collisions. Anything hitting it will not get through the material to the other side!

If the asteroid orbits within the habitable zone, all heat signals coming-out from the activity within will be masked by the sun's heat.


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