Malgrovian gliders inhabit the middle layers of the atmosphere of Malgrov, a gas dwarf. They spend most of their life gliding, preying on giant balloon-like floating lifeforms. When they get older, they slow down and begin falling. The two brown things on the top are egg sacs that are covered by a relatively thin membrane. This membrane bursts when the external pressure becomes great enough, releasing small, floating eggs that get back into habitable regions of the atmosphere while the parent dies and becomes food for creatures living near the surface.

The gliders have developed a certain level of understanding in the field of aerodynamics and ballistics in order to hunt and travel more effectively.

It can be assumed that the tissue of the living balloons hunted by the gliders is rigid enough to protect against an external vacuum.

The significant atmosphere of Malgrov extends to a height of about 400 km, with a surface pressure of about 2600 bar. Malgrovian gliders live in the central layers and feel comfortable in pressures between 1 and 5 bar. They posess several claw-tentacles they use to hook onto and cut through the flesh of the living balloons.

It can also be assumed that the atmosphere is populated by flora and fauna resembling species theoretized to live on gas giants.

My question is:

How can the Malgrovian gliders succesfully develop space travel? Can they attain orbital flight capability or at least perform suborbital flights and return safely?

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    $\begingroup$ they cant, if they are really gliders they cant "glide" without air. Nor can they build up the speed for escape velocity. $\endgroup$
    – anon
    Dec 26, 2017 at 23:50
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    $\begingroup$ Fascinating question setup, so +1. Unfortunately, I don't see any reasonable way for them to develop intelligence, much less space flight. They don't have much of an environment to exploit. $\endgroup$
    – kingledion
    Dec 27, 2017 at 2:19
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    $\begingroup$ It's hard to imagine how the gliders could develop a material civilization. Let alone develop the technology necessary for space travel. @JerryTheC's answer about domesticating the balloon creatures seems like your best bet. I do agree it's a fascinating set-up. Good luck! I hope you get good answers. $\endgroup$
    – a4android
    Dec 27, 2017 at 3:01

3 Answers 3


Some big problems:

Materials: They're limited to what they can harvest from things living at their level. No mining....

Nowhere to put/store things: Since they can't land on the surface, one problem is that there's nowhere to store things or assemble things. You might get round this by domesticating some of the big balloons...

Where to get thrust from: They need to buid engines and fuel them somehow.

Life support: they need to be able to create a gas tight seal - and provide suitable life support.

Most likely method of succeeding:

1) Domesticate the giant balloons.

2) Use them (either individually or in herds) to provide a base to store/build things on.

3) Assume that whatever holds the balloons up is usable for fuel - maybe the balloons work at least partially on a hot air system, so (a) you can harvest whatever it is they combine/burn to produce heat and use that to produce the thrust you need; and presumably the skin is tough/resistant enough to build rocket engines out of (since the balloons need to do their hot air trick without setting fire to themselves).

This also gives you a heat source if you need to cook/melt/extract things from available material.

4) If the balloons have bladders that can store pressurised gas, that makes things simpler for building life support/ storing fuel.

5) Maybe whatever the balloons use for blood makes a quick setting glue when exposed to the atmosphere (would be useful for sealing wounds/punctures that might let lifting gas out). That lets you join things together...


There is an ancient sci-fi opera pc game called Ur Qan Masters. It has a race of sentient beings that inhabit a gas giant:

They are essentially sapient bags of gas (and a limited quantity of solid and/or liquid) that float through their homeworld's atmosphere. Their visual range is different from most races and it is to their great dismay when they realize that their bodies are transparent to human vision, revealing their reproductive organs, which look like "glowy bits".

Just like humans, these beings have a hard time facing low atmospheric pressures:

Because of their unique physiology, the Slylandro inhabit only a 500 kilometer thick layer in the the atmosphere of Source. Ascending above this layer, into what the Slylandro call "Void", causes them to become giddy and behave inappropriately.

Since a gas giant doesn't offer much in terms of raw materials, they had to resort to external help to explore space.

They are physically incapable of leaving their planet and travelling thru space, which prompted them to purchase a "Catalog Item 2418-B: Self-Replicating Robot Explorer Probe" from the Melnorme to explore space for them and report back to them.

Unfortunately for your creatures, there isn't much thay they can do differently from the Slylandro. There is no scientifically feasible way for them to build a ship. It takes the blood of 350 human male adults to have enough iron to forge a single sword, so think about how creatures that can only harvest materials by killing other creatures are going to build a ship.

The best they can do is penetrate a bigger creature to use it as some sort of casing, then throw themselves into a storm and hope it accelerates them into a suborbital path. Would be quite the ride, and there are risks. They may be thrown into abyssal depths. Or they may risk achieving escape velocity, and in that case they will never get back to the gas giant.

Achieving proper orbit requires maneuvering while on a suborbital path... But simply expelling gas is would not provide enough delta-v for that.


There might be a way. It is very unlikely though:

If they have an airfoil shape and can produce thrust, they can spin themselves out of the atmosphere. The faster they go, the higher they fly. They could, over time harden themselves to lower and lower pressures and be able to thrust for longer times. They could achieve sub orbital, orbital and escape velocities. They have to be able to survive a vacuum, cold, heat and radiation for extended lengths of time.

Look at JP Aerospace's Airship to Orbit (ATO) for a non-biological example of this.

The biggest evolutionary question, is: what is the first step that made it more likely for them to survive? What is in the upper atmosphere that they cannot get lower? What is in the vacuum that they can't get lower? I can think of two things that could drive this, predators in the lower atmosphere and stronger sunlight and radiation at higher elevations (or maybe they are the predators chasing prey).

As other's have stated, sentience is unlikely. There's just not that much to interact with up there. Spending a lot of energy on the hardware for thinking won't give much of a survival increase.

Also, technology is pretty much out of the question. What would they need to build and what would they build it with?


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