My idea is to have a place that is "inescapable" by any conventional propulsion system, except it has Earth-like conditions: a breathable atmosphere, 1.0g gravity, etc.

What would have to be the composition of a planet in order to make it virtually "inescapable"?

I've considered placing it near the event horizon of a black hole or having the atmosphere be simply much "thicker" than earth's 300m/480km atmosphere but I was wondering if there is a scientific reason why a ship would suddenly just "stop working" at a certain altitude, magnetic force, etc.

How could an earth-like planet be impossible to leave?

  • 1
    $\begingroup$ You can have a surface gravity of 1g on a body with a really enormous mass, like a dyson sphere surrounding a star as I outlined in this answer, and this can lead to a very high escape velocity that's a significant fraction of light speed as discussed in this answer...not impossible to escape, but would at least require some very advanced propulsion technology far beyond chemical rockets. $\endgroup$
    – Hypnosifl
    Jul 23, 2016 at 4:14
  • $\begingroup$ "I was wondering if there is a scientific reason why a ship would suddenly just "stop working" at a certain altitude, magnetic force, etc." The real universe does not work like that. Stories and TV shows may sometimes use ideas like that, but they are just relying on people not understanding these things to get away with lazy plot design. $\endgroup$ Jul 23, 2016 at 9:26
  • $\begingroup$ See Missle Gap by Charles Stross. $\endgroup$
    – JDługosz
    Jul 23, 2016 at 14:16

5 Answers 5


Well, the obvious answer to me is the reason why we cancel launches in our world. The weather. Here is a long boring NASA article about the weather conditions. Basically, if your planet was too windy, to stormy, to much lightning, etc, launching a rocket could be disastrous.

  • 1
    $\begingroup$ Beautiful and so simple. This got my upvote. A tidally locked planet around a red dwarf would be extremely stormy. $\endgroup$
    – a4android
    Jul 23, 2016 at 3:53
  • $\begingroup$ The issue with this is that the planet would be a very harsh and inhospitable place. The story I have in mind is that the planet is "conducive to life" but impossible to leave...like a perfect prison. (dun dun!) $\endgroup$
    – GideonKain
    Jul 23, 2016 at 4:00
  • 1
    $\begingroup$ Just because its always raining doesnt mean its inhospitable, just not conducive to launches. The rainiest place on Earth is Meghalaya, India and it is still populated. $\endgroup$
    – Keltari
    Jul 23, 2016 at 4:44
  • $\begingroup$ Yeah -- Rocketry is a VFR operation! $\endgroup$
    – Shalvenay
    Jul 23, 2016 at 6:01
  • $\begingroup$ However, if the weather makes it impossible to leave, wouldn't it also make it impossible to land there? $\endgroup$
    – celtschk
    Jul 23, 2016 at 16:29

Better to get rid of the black hole as that has too many other problems. Also, of itself it might not be an effective condition for inescapeability. Ditto having a super-deep atmosphere of 300-480 km, simply because the planet begins to be something like a mini-Neptune.

If your planet orbits an extremely active star, possibly a flare star, then its equivalent of the Van Allen radiation belts could be ultra-deadly. At least, they would have to be sufficiently lethal that astronauts had an extremely elevated risk of dying from radiation sickness.

Super-strength radiation belts could be more extensively developed around the planet. Many more belts and coming down close to the top of the planet's atmosphere. On the plus side, this would be a planet with incredible auroras. Night skies filled with beautiful shimmering veils of light.

While this does allow spaceships to actually leave the planet. Anyone in the vessel will be dead reasonably soon after departure. This could be six months later, but that's enough to stop interplanetary travel and, even, their equivalent of Earth-Moon flights.

The most suitable flare star could be a red dwarf. Yes that does most likely mean it would be tidally locked and the weather be extremely stormy.

This means your planet would be inescapable because of the double jeopardy of permanently bad weather and a shimmering shroud of lethal radiation.


Maybe look into Kessler syndrome?

As you may or may not know, Kessler syndrome/an ablation cascade is a sort of feedback loop where a collision between space objects creates fragments of space debris, that then can collide with more and more space debris, with the potential for subsequent collisions rising exponentially.

All of this debris is traveling incredibly fast and can easily damage manned spacecraft. If you've seen Alfonso Cuarón's film "Gravity" the idea is pretty familiar.

An extreme ablation cascade could make riding a rocket into space something like riding a firecracker into a saw blade.

I'd recommend the Wikipedia article for more information and a better description. https://en.wikipedia.org/wiki/Kessler_syndrome


Perhaps this particular idea isn't too great because the planet would have had to have been "escapable" to begin with. Or perhaps it's a side-effect of whatever makes the planet inescapable.

Another thought: maybe in their own desperation to get to the stars, they've doomed themselves to the ground.

Just another idea to play with. I think it's a cool one.


Intensely strong solar winds coupled with a fast moving planetary core? The radiation level will kill any living organism that gets past the ionosphere. It's only the planets own powerful magnetic field and supercharged ionosphere that allows life to exist.


If a non-physical answer is acceptable, then I think you could use religion and ideology as a way of keeping the populace on the ground. From your description this isn't what you're looking for, mostly because the civilisation you have seems very advanced (they're investigating space flight). However, if this religion was fairly new, say it arose with the advent of modern technology, then it could provide a reason for not ever building spaceships in the first place.

That said, I think the best bet for a physical limitation is one that's already been proposed: a very stormy planet.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .