What would space crafts designed by aliens living in an aquatic world be like?

[RainDreamer]

So recently I had a look at the sea dragon designs and realized it is probably the one and only rocket designed to launch directly from the sea without any sort of external launch platform. That makes me wonder, what would space craft designed by an alien race living in a world that has no dry landmass be like? They would need to launch things directly from the water surface. Furthermore, since they are from an aquatic world, it is likely they will also breath in liquid as well, and instead of breathable air tanks, they would need to use water tanks, which add much more mass to their space craft design, and that may drastically change the way they operate them.

 

In short, the question is:

What are some possible space craft designs for an aquatic alien race, given:

a) their world has no dry landmass

b) they breathe liquid

 

What kind of liquid they breath,what kind of anatomy they have, what their culture/society/technology is like, and what the size/composition of their world will be is up to your imagination.

Edited April 12, 2016 by RainDreamer

[Spaceception]

No clue, but I'm sure someone will be able to answer.

[Snark]

Of course, there's also the question of whether a purely-aquatic species would ever develop space travel in the first place, since it's kind of hard to have a space program (or the technologies that lead up to it) without, say, metals, and metals are kinda of hard to have without fire, and I would imagine that would be a technical challenge.

The closest I've seen to a science-fiction treatment of this idea is Startide Rising by David Brin, in which the main characters are a crew of genetically-engineered sentient dolphins from Earth.  It raises the interesting question of "what if the aquatic creatures in question are air-breathers", since separating air and water in zero gee is an ugly problem.  The solution in the book is that they're breathing "oxy-water", a highly-oxygenated liquid that's uncomfortable to breathe, but air-breathing creatures can get enough O₂ out of it to live.  (And has some real-world research supporting it.)

However, the book doesn't really address your question.  It's far-future science fiction (so it uses a lot of magical sci-fi technologies), isn't a purely aquatic race, and they didn't have to build the ship for themselves.

[Spaceception]

3 hours ago, Snark said:

Of course, there's also the question of whether a purely-aquatic species would ever develop space travel in the first place, since it's kind of hard to have a space program (or the technologies that lead up to it) without, say, metals, and metals are kinda of hard to have without fire, and I would imagine that would be a technical challenge.

Could they use some sort of method using volcano vents?

[Nibb31]

Without opposable thumbs, it would be hard to develop tools. Even if dolphins developed language, social structures, and a rich oral culture, they would be limited by their relative inability to modify their environment or to construct tools.

[Rakaydos]

So presume an aquatic species that has opposable thumbs, or equivilant. A rocket built by squid?

[Snark]

40 minutes ago, Spaceception said:

Could they use some sort of method using volcano vents?

I suppose we can posit anything we like ... but that seems really unlikely to me.  It'll get really hot, yes.  But how hot is "hot"?  It'll certainly get kill-you hot, but not smelt-hematite-into-iron hot.

Bear in mind that underwater volcano vents are surrounded by water, which conducts/convects heat away quickly, and (if it gets above the boiling point) vaporizes the heat away very quickly.  In an aquatic environment, it's basically impossible to have anything that's a lot hotter than the water around it.

Not to mention that heat would be limited just to a few specific vents. How would our civilization have developed if the only place you could make a fire would be a few dozen places around the planet, such as the peak of Mauna Kea?

And also bear in mind that this kind of heat source is big and dangerous and how do you get close enough to it to do something useful with it without getting yourself killed?

And how would you discover all this in the first place, anyway?  We don't have any records of this, of course, but I assume that we discovered metal because we were using fire for practical purposes, a lot, all over the world, for thousands of years, and eventually somebody noticed that this funny shiny stuff comes out of the rock if you put it in the fire.

So I have to say this would be a pretty implausible scenario to me.

[RainDreamer]

40 minutes ago, Spaceception said:

Could they use some sort of method using volcano vents?

Sounds interesting. Volcanic factories at bottom of the sea. Which leads to an offtopic note: Aquatic aliens are probably serious environmentalist, since pollution in liquid is horrible, and  they have no where else but underground to dump waste.

 

1 minute ago, Nibb31 said:

Without opposable thumbs, it would be hard to develop tools. Even if dolphins developed language, social structures, and a rich oral culture, they would be limited by their relative inability to modify their environment or to construct tools.

The alien race's anatomy is up to your imagination here, the question in OP assumes they have the necessary anatomy to be intelligent and capable of developing required technology for space without specifying them.

[Snark]

11 minutes ago, Nibb31 said:

Without opposable thumbs, it would be hard to develop tools. Even if dolphins developed language, social structures, and a rich oral culture, they would be limited by their relative inability to modify their environment or to construct tools.

Sure, which is another way that the Startide Rising book I mentioned isn't really a great match for the OP's question.  The dolphins in question are genetically engineered by humans, have been assisted and trained by humans, and can do work by strapping into electromechanical contraptions built for them by humans which plug into a direct neural jack.  Like I said, magical far-future sci-fi.

I was merely giving it as an example of "the closest thing I've seen in SF to an aquatic star-traveling species"... not "close". 

[monstah]

Interesting topic! I'd just like to add something in relation to Snark's remark on oxy-water, that has real-life research into it. Remember the movie The Abyss, where they use breathable liquid to pressurize the suit for going really deep? That's real (sorta) (ctrl-F for "breathable"). The fluid worked, but it was dangerous; Ed Harris held his breath while shooting, but the rat wasn't so lucky (and survived, anyway).

[todofwar]

I don't think it's impossible. I'm curious what their whole civilization would look like, probably much more 3 dimensional planning than our own buildings. They could start out using shells and bones as tools, eventually someone might find some deposits of elemental metal or they would use obsidian. There are chemical methods for producing metals as well, but how their chemical industry would develop is its own can of worms.

[Rakaydos]

Keep in mind, water is heavy. Theit life support requirements wll be much harsher than our own.

[kerbiloid]

Without any metallurgy their technical progress would be limited with organic constructions and enormous number of glues.

[RainDreamer]

2 minutes ago, Rakaydos said:

Keep in mind, water is heavy. Theit life support requirements wll be much harsher than our own.

On the bright side, they don't need to have separate tanks for clean water and breathable air, so it reduce space requirement. Might be a negligible advantage though.

[kerbiloid]

2 minutes ago, RainDreamer said:

On the bright side, they don't need to have separate tanks for clean water and breathable air, so it reduce space requirement.

Ha-ha. If you have a fish tank, you would keep it enough large to prevent it from pollution.

[RainDreamer]

6 minutes ago, kerbiloid said:

Ha-ha. If you have a fish tank, you would keep it enough large to prevent it from pollution.

I mean can't their breathable liquid cycle be like: breathable liquid tank -> hab space -> wastewater tank -> filter and treatment -> breathable liquid tank? Human space craft need two systems to deal with life support between water and air since we don't breathe in water, but we still need it to live. 

Edited April 12, 2016 by RainDreamer

[kerbiloid]

If you have an aquarium, you use an air compressor to enrich the water with oxygen.
Otherwise you get a bog.

Edited April 12, 2016 by kerbiloid

[RainDreamer]

They can always bring O2-enriched water in tanks? Just like what Snark mentioned above with the dolphin thing.

Edited April 12, 2016 by RainDreamer

[kerbiloid]

A human-sized animal requires 1 kg of Oxygen per day. This means a 5 kg pressurized cylinder.
Difference between water "poor" and "rich" with oxygen is ~1-2% of oxygen.
So, you would get a huge basin to replace water in a small tank.
Or - a 5 kg cylinder.

Some necessary conditions to get a civilized lifeform:
1. Some actuators like "arms+hands". Absolutely useless for fish-shaped animal. Absolutely great for bottom dwellers.
2. Ability to collect items, store a food. Unavailable for fishes. Lifestyle of bottom dwellers.
3. Ability to use and transform the surrounding media for attack and defence. Poorly available for fishes. Lifestyle of bottom dwellers.
4. Ability to consume different types of food to prevent mass extictions. More or less available for fishes. Lifestyle of bottom dwellers.
So, the only oceanic lifeform able to achieve at least a stone age level is either Kraken, or (ta-dam!) Mantis Shrimp.

Edited April 12, 2016 by kerbiloid

[RainDreamer]

4 minutes ago, kerbiloid said:

A human-sized animal requires 1 kg of Oxygen per day. This means a 5 kg pressurized cylinder.
Difference between water "poor" and "rich" with oxygen is ~1-2% of oxygen.
So, you would get a huge basin to replace water in a small tank.
Or - a 5 kg cylinder.

Ah, that makes sense. I supposed that would work like current human space craft then, with CO2 scrubber, just working with water, along with filters and stuff to clean the hab water. They get to do all of that in one system working with water though, so is that still (negligible) saving in space requirement?

[kerbiloid]

And instead of several kilograms of air they need to permanently pump several dozens tonnes of water.

[KAL 9000]

27 minutes ago, kerbiloid said:

A human-sized animal requires 1 kg of Oxygen per day. This means a 5 kg pressurized cylinder.
Difference between water "poor" and "rich" with oxygen is ~1-2% of oxygen.
So, you would get a huge basin to replace water in a small tank.
Or - a 5 kg cylinder.

Some necessary conditions to get a civilized lifeform:
1. Some actuators like "arms+hands". Absolutely useless for fish-shaped animal. Absolutely great for bottom dwellers.
2. Ability to collect items, store a food. Unavailable for fishes. Lifestyle of bottom dwellers.
3. Ability to use and transform the surrounding media for attack and defence. Poorly available for fishes. Lifestyle of bottom dwellers.
4. Ability to consume different types of food to prevent mass extictions. More or less available for fishes. Lifestyle of bottom dwellers.
So, the only oceanic lifeform able to achieve at least a stone age level is either Kraken, or (ta-dam!) Mantis Shrimp.

Kraken? Maybe they had a space program and eventually evolved to just not need any life support in space. Now they eat passing Kerbal ships .

Edited April 12, 2016 by KAL 9000

[RainDreamer]

28 minutes ago, kerbiloid said:

Some necessary conditions to get a civilized lifeform:
1. Some actuators like "arms+hands". Absolutely useless for fish-shaped animal. Absolutely great for bottom dwellers.
2. Ability to collect items, store a food. Unavailable for fishes. Lifestyle of bottom dwellers.
3. Ability to use and transform the surrounding media for attack and defence. Poorly available for fishes. Lifestyle of bottom dwellers.
4. Ability to consume different types of food to prevent mass extictions. More or less available for fishes. Lifestyle of bottom dwellers.
So, the only oceanic lifeform able to achieve at least a stone age level is either Kraken, or (ta-dam!) Mantis Shrimp.

Another point to that, is as mentioned above, they need to be able to develop metallurgy, and require heat that is likely coming from volcanic vent at sea floor, which means another point for bottom dweller!

 

Unless they somehow develop/evolve a way to "grow" their tech organically, that is.

[kerbiloid]

It's enough hard to develop metallurgy when the molten iron contacts with water which cools it down.
An iron metallurgy is unavailable for them because they just couldn't build a smelter with dry coke and oxygen-rich air, People did that only in XVIII centurt.

Copper, lead - maybe.

Also there is water. Axes, hammers and arrows are useless due to the drag force. The only purpose of metal instruments: pins and pikes. But they have enough bones and poisons foir it.
 

Edited April 12, 2016 by kerbiloid

[pincushionman]

Remember also, liquids are heavy and incompressible. Water is something like 800 times denser than air. Could we have even gotten to space, let alone the moon, if instead of hauling up 170 kg of hab-volume air in Apollo, we were hauling up 140 tonnes of agua? Probably yes, but even the Mercury-equivalent would have been freakin' enormous.