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I'm looking for something that would prevent humans being able to establish the use of satellites on an alien planet, but also would not prevent humans from living on the planet, or life developing on that planet.

Humans must also be able to arrive onto and leave the planet, not necessarily at any point in time, but have the availability to do it at least on occasion (i.e. they're not stranded on the planet).

It's not absolutely necessary that satellites cannot be physically in orbit, but rather there could be something that affects how the satellites work, meaning that they cannot reliably be used for transmitting information.

I did think of solar flares as a method of disruption, but as far as I'm aware having solar flares often and strong enough that it would consistently disrupt satellite communication would require the planet to be orbiting (or close to) a star unstable enough that life could not reliably reside there, though I may be wrong.

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    $\begingroup$ It must be natural, right? $\endgroup$ – Mołot Feb 21 '17 at 15:53
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    $\begingroup$ @Mołot preferably, yes, though it isn't a necessity. $\endgroup$ – Mike.C.Ford Feb 21 '17 at 16:03
  • $\begingroup$ The solar flares wouldn't be as much of a problem for anyone living within the magnetosphere, though they might get more black-outs than us if they had an electrical grid system. $\endgroup$ – Jon Hanna Feb 22 '17 at 1:15
  • $\begingroup$ Ever play Subnautica? ;) $\endgroup$ – Timpanus Feb 23 '17 at 1:39
  • $\begingroup$ Geostationary orbit, or any orbit? Geostationary orbit requires 35.8km altitude, so it could get crowded, or littered with debris. There are alternative types of orbits, but geostationary is usually the most useful. $\endgroup$ – smci Feb 23 '17 at 22:54

14 Answers 14

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Have a very wide ring

If you have a ring around your planet, it will be above the equator of it. This means that if it is sufficiently wide, every possible reasonable (as in cost, orbital velocity, distance to atmosphere) orbit will pass through it. Now unlike asteroid belts, rings are made up of lots of tiny (1/2 mm to meters) rocks, bits of ice, and dust. As anyone will tell you, it is a bad idea to walk, or even drive through a rock/sand/dust-fall if there is even such a thing. By the same logic, you don't want to have a satellite going through a ring-system.

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    $\begingroup$ I think this is true in general, however the gravity of moons and moonlets cause gaps to appear in Saturn's ring system. The Cassini mission, which has been in orbit around Saturn since 2004, is making passes through Saturn's rings on its way to its eventual death in Saturn's atmosphere. If you line up your passes just right through the gaps, you can get through the ring just fine. That requires precision and a good understanding of the system, though. $\endgroup$ – Cody Feb 21 '17 at 18:56
  • $\begingroup$ @Cody Which you would expect the motivated inhabitants of the planet to have, as the Cassini mission showed this to be quite feasible. $\endgroup$ – Mad Physicist Feb 24 '17 at 14:33
  • $\begingroup$ @MadPhysicist erm... the inhabitants are human colonists, no? that is what I read, at least. $\endgroup$ – Mark Gardner Feb 25 '17 at 6:50
  • $\begingroup$ @MarkGardner. I was affirming Cody's statement. I don't think there is any disagreement between any of us. $\endgroup$ – Mad Physicist Feb 25 '17 at 20:47
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There is increasing concern about space junk threatening our own satellites. By space junk I mean pieces of metal in orbit that can hit and disable satellites.

The space debris scene in the movie Gravity is really well done, I thought. https://www.youtube.com/watch?v=prlIhY3e04k

It has been suggested that a technologically outclassed enemy like North Korea could level the playing field by shooting payloads full of gravel into orbit and scouring down all the satellites.

If a planet had a lot of orbiting debris, it would be more difficult to place satellites. Maybe space debris in orbit is a result of a prior event like a war (which would make for cool writing opportunities as regards the exact nature of the debris). Maybe volcanic activity launches material into orbit periodically.

Maybe satellites in this scenario would need something like the AEGIS system to target and deflect incoming debris. The debris is small and comes fast but should be really obvious to radar. AEGIS satellite shotguns could shoot plastic cased mercury shot - mercury for the mass and because once the plastic disintegrates in the hard UV of space, the mercury will sublimate to molecules and not itself pose a threat.

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    $\begingroup$ I like this solution. "Why can't we put satellites in space? Because there's too many satellites careening around in space already!" $\endgroup$ – Cort Ammon Feb 21 '17 at 16:17
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    $\begingroup$ Relevant discussion concerning volcanic debris in space. $\endgroup$ – Frostfyre Feb 21 '17 at 16:23
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    $\begingroup$ That reminds me of Yogi Bera's famous quip "Nobody goes there anymore. It's too crowded." $\endgroup$ – Charles Burge Feb 21 '17 at 17:51
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    $\begingroup$ The difference between getting a spaceship down to the planet vs orbiting a satellite is the difference between running your bike across the highway and riding along down the highway. Stuff in orbit stays right in the path of the debris. $\endgroup$ – Willk Feb 21 '17 at 18:52
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    $\begingroup$ This is known as Kessler syndrome. $\endgroup$ – bob0the0mighty Feb 21 '17 at 19:46
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Binary planets! The gravitational fluctuation of two equal planet sized objects closely orbiting each other would make a stable satellite orbit near either planet pretty much impossible as the satellite would experience shifting amounts of gravity from the other planet, getting flung either away from or into the planet. You should still be able to launch from/land at either planet if you quickly move far away enough from the planets.

It probably wouldn't be a very comfortable place to live in as the gravitational tug of war would make both planets quite tectonically active leading to lots of volcanic eruptions etc. but it could be habitable. In fact, earthlike binary planets seem quite possible.

Also, it would be cool as hell.

Edit: After some more research it seems that the planets would tidally lock and circularize their orbits over time, as this is happening they would experience shifting amounts of gravitational pull, influencing tectonics and making stable satellite orbits around one of the planets extremely difficult. This gravitational "drag" also causes the circularization. When the orbits have become circular and the planets tidally locked geosynchronous satellites might become a possibility. After all, if the planets are tidally locked in a circular orbit a geosynchronous satellite would have a constant distance to both objects. This does ignore the influence of whatever star they are both orbiting around, the star's gravitational influence might prevent proper circularization.

So, the difficulty of maintaining satellites is going to depend a lot on the eccentricity of the orbits. As to how long it takes for circularization to occur and if that time span is long enough for the planet to become suitable to life before the orbits are circular, I have no idea.

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    $\begingroup$ I voted for this because it would be very cool. But Earth has a big moon and we can have satellites. I think this will require some quality time with a gravity simulator: 2 planets in stable orbit around each other, 1 with a tiny satellite. $\endgroup$ – Willk Feb 21 '17 at 19:00
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    $\begingroup$ The moon is only about 1% of Earth's mass though, but also the gravitational effects are going to depend massively on how close the two planets are orbiting one another. $\endgroup$ – Koen vd H Feb 21 '17 at 21:11
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    $\begingroup$ A small low-orbit satellite is practically at ground level, looked at from 100,000 km away. If you put the second planet so close that it knocks those satellites out of orbit, check to see if the planet is still habitable. How does it hold onto its atmosphere, for example? $\endgroup$ – David K Feb 22 '17 at 5:29
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    $\begingroup$ @Ben On the other hand, low orbit isn't all that useful, and those satellites don't always stay up. Geosynchronous satellites might be impossible, communications satellites might be too hard to use, GPS constellations would be too hard to predict even if they did somehow manage to stay in orbit. So my question is do we have to rule out all possible satellites or just the vast majority of the ones that are useful? $\endgroup$ – David K Feb 22 '17 at 6:49
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    $\begingroup$ Why don't both planets use each others' infrastructure as satellites. $\endgroup$ – Suhrid Mulay Feb 22 '17 at 14:42
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The planet could have wildly inconsistent gravity.

Gravity on Earth is non uniform, though it's hard to tell because of the variations are slight.

enter image description here

But if this planet had a large super dense mass (from a foreign body impact?) in one area then you could have a spot where the gravity is much higher than the rest of the planet.

This would affect satellites in two ways:

  1. Orbits would be hard because the higher gravity would pull the satellite off course and degrade the orbit rapidly.
  2. The atmosphere would be pulled in very tight over the anomaly, and balloon out elsewhere. The satellite passing through the expanded atmosphere would experience drag and have its orbit degraded.
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    $\begingroup$ I'd add that such problem is not hypothetical but actually affects satellites put around the Moon. en.wikipedia.org/wiki/Lunar_orbit $\endgroup$ – Shadow1024 Feb 21 '17 at 20:28
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    $\begingroup$ The actual effects of the higher dipoles of Earth gravitational field are analyzed in some detail in arxiv.org/abs/1309.5244 . $\endgroup$ – dmckee Feb 21 '17 at 21:21
  • $\begingroup$ How would that affect the habitability of the planet though? $\endgroup$ – Mad Physicist Feb 24 '17 at 14:33
  • $\begingroup$ @MadPhysicist It wouldn't affect it much, except that you'd weigh a bit more in one area than in another. For instance It might be 1.25g or 1.5g in that area, high enough that you'd actually notice a difference, but not enough that you'd suffer, and the transition would be somewhat gradual, like climbing up a mountain and all the sudden noticing that it's harder to breath because the air is thin. The biggest thing would be how it would effect the weather. Air would be pulled down more, making a higher pressure area, which would flow out constantly as a lot of wind. $\endgroup$ – AndyD273 Feb 24 '17 at 16:07
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AndyD273 has half the answer. Consider the case of being very difficult to orbit the Moon (Shadow1024 posted quotes in his answer, below): close orbits are unstable because the body is lumpy, which is the case Andy shows. But more distant orbits won’t work either because such a body would be grabbed by the Earth.

hill sphere

From the illustration you can see that the highest possible orbit is bounded by L1 and L2.

So, make your habitable world a moon of a gas giant, with a similar situation.

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  • $\begingroup$ I think a high orbit would still be hard even without another larger body? The orbit would still be erratic as you're orbiting around the dense mass which is constantly rotating to be at a different distance from the satellite. I also wonder if one side of the planet was denser than the other, if the rotation would be also be erratic, since the center of gravity would be away from the exact center of the planet, like a top with a penny taped on one side. $\endgroup$ – AndyD273 Feb 21 '17 at 18:48
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    $\begingroup$ @AndyD273 technically it’s still chaotic but it can be stable over geologic time scales. As the orbit gets larger, the primary better approaches a point. To the extent that it’s not, the peturbations are random and tend to cancel out. The eccentricity needed to crash is rediculus, and the usual forces are still present to circularize the orbit over time. $\endgroup$ – JDługosz Feb 22 '17 at 2:30
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Have we ruled out permanent, pervasive weather conditions? If the planet was wrapped in constant high-energy storms and if the upper layers were full of light-refracting ice crystals and radio-disruptive discharges, the colonists could launch as many satellites as they wanted to. They just couldn't ever communicate with them (either by radio or laser), once they were launched.

A satellite that you can't talk to is... just a pretty light in the sky not even a pretty light in the sky. It's just gone, up there above the clouds.

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  • $\begingroup$ If there's a visible light in the sky then you can talk to it, even if that "talking" is limited to flashing that light with Morse code. $\endgroup$ – Spudley Feb 22 '17 at 21:20
  • $\begingroup$ @Spudley! Thanks for catching my oversight. I think my fix covers it. $\endgroup$ – Henry Taylor Feb 23 '17 at 0:21
  • $\begingroup$ indeed. so you may have an upvote :) $\endgroup$ – Spudley Feb 23 '17 at 20:47
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Adding some detail to suggestions already above.

1) Van Allen radiation belts. The planet's magnetic field is of a strength that it's Van Allen belts are particularly hostile. Not enough to be fatal to humans on a ship passing through down to the surface and then off-planet, but enough that after a few hours in orbit any satellite would become disabled by energetic particles, and there's so much radio "noise" that signals would be lost in the background. Fun addition: you can have a plan to "drain" the belts as part of the story, so they can have satellites again, or that a solar storm blows away the belts temporarily either as a one-time event or a regular occurrence on a long time scale.

2) A wickedly active ionosphere. Energized particles (through solar, geomagnetic, or huge lightning storms) in the upper atmosphere block all radio communication back to the ground. You can launch a satellite, but any signal you send up bounces back (and vice versa), so you can't talk to it. Between clouds, aurora, and lightning, optical (laser) communications to space are horked too. Fun possibility with such a reflective ionosphere is that you can possibly bounce terrestrial radio signals all over the planet... HAM type radio operators could talk and listen to the whole world.

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Meteor showers. Really, really intense meteor showers.

Suppose that several plumes of small rocks are orbiting the same star as this planet in highly eccentric orbits, containing an extremely large number of such rocks, collectively the mass of a planet or more broken into tiny bits.

Each time the habitable planet's orbit intersects the orbits of one of these plumes, the rocks light up the entire night sky like the finale of a fireworks show (and would light up the day sky too if the star weren't so bright), unlike the relatively tame meteor showers we get on Earth. Anything in the vicinity of the planet above the upper atmosphere at that time is either perforated by the accompanying dust or destroyed completely by collision with one of the larger pieces.

In between meteor showers, spaceships can come and go safely. Just be careful not to get caught in one, and forget about parking anything in orbit for any extended period of time.

If the planet's orbit is close to the periastron of the rocks, they'll catch up to it from behind at high speed, less than the difference between the planet's orbital speed and escape velocity from the star, but not necessarily much less. If the planet is near the apastron of the rocks, it will plow through them while they are relatively stationary. At some point in between, the rocks hit the night side of the planet on the way in toward the star and the day side on the way out.

Life may even be a little precarious on this planet, as mixed in with these billions of tiny projectiles that burn up in the atmosphere there are a few rocks large enough to make it to the surface, some large enough to create large craters. The really big ones are few and far enough between, however, that the local biome has always recovered from these meteor strikes, and there's a reasonable opportunity to establish a human colony with the wherewithal to detect and deflect any rock large enough to be a threat to the colony's existence.

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Solution for a Killsat Planet: the Moon like situation.

Quoting NASA:

"High-altitude circular orbits around the Moon are unstable," says Todd A. Ely, senior engineer for guidance, navigation, and control at NASA's Jet Propulsion Laboratory. "Put a satellite into a circular lunar orbit above an altitude of about 750 miles (1200 km) and it'll either crash into the lunar surface or it'll be flung away from the Moon altogether in a hyperbolic orbit." Depending on the specific orbit, this can happen fast: within tens of days. Why? Earth is responsible. The gravity of massive Earth only 240,000 miles (400,000 km) from the Moon constantly tugs on lunar satellites. For a lunar orbit higher than 750 miles, Earth's pull is actually strong enough to whisk a spacecraft out of the game. https://science.nasa.gov/science-news/science-at-nasa/2006/30nov_highorbit

And:

"Lunar mascons make most low lunar orbits unstable," says Konopliv. As a satellite passes 50 or 60 miles overhead, the mascons pull it forward, back, left, right, or down, the exact direction and magnitude of the tugging depends on the satellite's trajectory. Absent any periodic boosts from onboard rockets to correct the orbit, most satellites released into low lunar orbits (under about 60 miles or 100 km) will eventually crash into the Moon. PFS-2 released by Apollo 16 was simply a dramatic worst-case example. But even its longer-lived predecessor PFS-1 (released by Apollo 15) literally bit the dust in January 1973 after less than a year and a half. https://science.nasa.gov/science-news/science-at-nasa/2006/06nov_loworbit

To make it perfect:

-Make the planet a bit heavier and with a bit denser atmosphere... Just to put extra effort on launching anything and increase any low orbit decay

-To get properly heavy body in vicinity - put the planet around a tiny, dim red dwarf. (just don't forget about tidal lock, but it's mostly a story thing and not survivalibity issue)

-Oh... Red dwarfs tend to be a flare stars... I should not matter much for a planet protected with a thick atmosphere, right? ;)

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  • $\begingroup$ Moon-like situation is what I answered earlier. $\endgroup$ – JDługosz Feb 22 '17 at 2:39
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The human-tolerable atmosphere is incredibly thin--they wouldn't even dream of building skyscrapers due to those shifting, capricious places on the planet where it is practically non-existent (life in that environment is a whole story in itself! ).

Above the super thin breathable air are layers of electrical charge diversity that for some reason causes continual high-volume lightning strikes to occur between those layers of the upper atmosphere while only rarely discharging down to the planet surface.

On this planet they use spacecraft with electrical shielding technology to get through the atmosphere, the people love one-story buildings with elaborate underground living areas, and the night shows are appreciated like a lovely sunrise or sunset.

And they don't send communication satellites into orbit.

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    $\begingroup$ But a super-thin atmosphere would actually lower the delta-V required to launch satellites by an order of magnitude (due to lack of aerodynamic drag during launch). Even if the sats would fail in the upper layers, it would still be way cheaper to send anything into orbit. $\endgroup$ – IvanSanchez Feb 22 '17 at 11:32
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    $\begingroup$ I think N2ition's idea isn't that you can't orbit a sat, but that you can't talk to a sat once it's been placed in orbit; the EMI from the storm layers would act like a fairly full spectrum radio jammer. This has a bonus for story ability, tech can only talk on its side of the constant lightning storm. Ground based radio works, to other ground stations. People out in space can talk to other people in space. But ground to space comms are jammed. To call Earth you'd have to shuttle hard copy to orbit, then transmit from there... $\endgroup$ – Ruscal Feb 22 '17 at 23:42
  • $\begingroup$ The question states that it is okay if the satellites are able to be physically in orbit beyond the atmosphere, but reliable information transmission is disrupted through it. $\endgroup$ – N2ition Feb 23 '17 at 0:23
  • $\begingroup$ Yes, I was only thinking of ground to orbit communication based on how the question was detailed. $\endgroup$ – N2ition Feb 23 '17 at 0:27
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Atmospheric drag.

The planet could have such a large atmosphere, or be contained inside a larger cloud of gas and/or dust, such that all reasonable orbits around said planet would be non-vacuum.

This would cause satellites to de-orbit on their own within a very short time due to drag, but not prevent active ships from traveling through it (albeit expensively). A satellite is by definition only kept in it's orbit by gravity/speed at launch. If it contains equipment to change it's orbit or actively maintain it, it's a ship.

Remember. Space =/= Vacuum.

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How about very strong solar radiation that renders satellites dead electrically in such a short period of time (matter of minutes or hours) that it's not worth even trying to launch them?

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    $\begingroup$ Note that the question specifically mentions solar activity of this magnitude not being a valid option, due to the very real chance of the world itself not being habitable. $\endgroup$ – Frostfyre Feb 21 '17 at 21:26
  • $\begingroup$ You might look into van Allen radiation belts. en.wikipedia.org/wiki/Van_Allen_radiation_belt $\endgroup$ – David Elm Feb 21 '17 at 22:50
  • $\begingroup$ This would require a super strong geo-magnetic shielding for the planet to remain habitable, but one that doesn't extend very far so it can't protect satellites. Earth's magnetosphere is our shield, and it protects a good chunk of our orbital systems. Just make it so that you can't climb this place's Everest because the top is above the magnetosphere and you'd rad out. That should quickly cook anything in orbit. $\endgroup$ – Ruscal Feb 22 '17 at 23:46
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Having worked in military satellite communications for about a decade I would have to say that you need a source of interference in the same range as whatever satellites you have that you can put up. On our own world certain entities use certain "bands" to communicate back and forth. A radio source either natural or man made compromising your satellite's transmit and/or receive will make most communications signals unusable. However if the planet is to remain unable to communicate the interference must be very broad and something that cannot be "fixed" easily. Without knowing whether the situation would be permanent or if it starts at some point and maybe ends at another I cannot go any further. Let me know because my husband was a military communications instructor and I can get him involved to find you a solution.

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I'm not very science-minded, a lot of the more detailed stuff just escapes me, but maybe multiple moons in low orbit would throw off the orbit of any satellites. This wouldn't disrupt the signal but would make it impossible for them to stay in orbit. Particularly if the moons were close together in their orbit which would make the satellites change from the orbit of the planet to the orbit of one moon to the orbit of the other moon, possibly even catapulting back into space.

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  • $\begingroup$ That doesn’t make physical sense. $\endgroup$ – JDługosz Feb 23 '17 at 13:20
  • $\begingroup$ Welcome to Worldbuilding, BTW! $\endgroup$ – JDługosz Feb 23 '17 at 13:20
  • $\begingroup$ well as I said, I only know the basics of science. I was thinking of all the scifi shows that have them slingshotting around a planet to gain speed and redirect back out into space, so if the gravity of multiple large objects were fighting maybe. and thanks :) $\endgroup$ – Guinevere Ellen Mayberry Feb 23 '17 at 13:50
  • $\begingroup$ The moons are not destabolizing each other, so it presupposes that stable orbits with multiple bodies are possible. Thus, the idea is self-contradictory. What's not physical is «moons close together in their orbit». Each moon must have its own orbit, and the only sharing possible is the “trojan points” which would not be close together and must be tiny. $\endgroup$ – JDługosz Feb 23 '17 at 14:31
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    $\begingroup$ that all makes sense. My idea wasn't entirely wrong, just not quite fine-tuned enough to answer the question. Thanks for helping to educate me :) $\endgroup$ – Guinevere Ellen Mayberry Feb 23 '17 at 15:26

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