Traversing the high seas has long been seen as a metaphor for exploring the space beyond Earth, especially in science fiction.
“On the clearest of nights, when the winds of the Etherium were calm and peaceful, the great merchant ships with their cargoes of Arcturian sura crystals felt safe and secure. Little did they suspect that they were pursued... by pirates!”
- Treasure Planet
Outer space has always been a place of metaphor. No other environment exists as far from the human experience, with the scale, the surroundings, and the contents all defying easy explanation. All other foreign environments can be understood as extreme versions of those we know: the Marianas Trench is just a very deep pool, and the peak of Everest is just a very tall hill. So when we can’t use anything we know as a direct analogue, we turn to the next closest thing. We did it for air travel, and now we’re doing it for space travel: we are using nautical terms.
Ocean travel is the go-to reference point for any situation involving long journeys (“bon voyage!”), hazardous conditions (“worse things happen at sea!”), or periods of extended isolation (“cabin fever”). Never before sea travel had humans prepared so much for long journeys through a hostile environment. In designing facilities for the landing and takeoff of planes, designers took seaports as a model: divided into ‘landside’ and ‘airside’, these ‘air-ports’ served ‘air-craft’, flown by accredited ‘pilots’; all terms originating at sea. In fact, the term ‘aeronautics’ literally means ‘sailing the air’!
It makes sense, then, that writers describing the new frontier of space should take similar inspiration. The Belgian writer J.-H. Rosny aîné wrote Les Navigateurs de l'Infini (The Navigators of Infinity) in 1925, describing the adventures of his ‘astronautique’ (space sailors) to Mars. The British Interplanetary Society, the earliest space advocacy organisation, canonised the term ‘astronaut’ in their 1934 bulletin. Humanity was to sail the new ocean.
If you were forced to pick an analogue for space travel, however, you could do far worse than a nautical one. Space shares a number of properties with the great blue expanse that covers our world, not the least of which is its hostility. Journeys through it must be made in complicated, self-contained vessels, piloted by an expertly trained crew, and may take many days to complete. Distances are extreme, and rest impossible. Food, water, and other basic amenities must be packed and rationed carefully to survive the trip, and your journey must be carefully planned. When you reach your destination, it will almost certainly be completely foreign to you, and may or may not provide a safe haven, with return to your home a difficult and uncertain prospect.
Spaceflight hasn’t yet reached the commercial operation of air and sea travel, however, and so much of these comparisons have yet to be made in reality. Much more of the nautical influence has been felt in science fiction, where writers have had to imagine voyages that may never happen, to places that may never exist. The easiest comparison is the description of space-faring vessels as spaceships, a practice which can be traced back as far as 1894, with John Jacob Astor’s A Journey in Other Worlds positing it as a natural extension of the seafaring ship.
Often, said spaceships will be classed just like a naval fleet, with cruisers, battleships, and destroyers ‘sailing’ in formation. These fleets will almost certainly be manned by ‘space marines’, lead by a captain and a team with naval rankings: officers, pilots, and commanders all fill the bridge of the Enterprise in Star Trek. The naval analogue seems to extend to the layouts of the ship as well. In addition to the bridge, the Enterprise also consists of fore and aft decks, a ‘brig’ for prisoners, and several outright references to sailing (Captain Picard keeps paintings of wooden ships in his office).
But alongside all of these subtle analogies, there are the occasional works that plunge, full speed ahead, into the sailing comparisons, and just embrace the similarities space shares with the sea. Space Battleship Yamato, a 1974 anime series, names its titular spaceship after the real-life Yamato, a famous battleship from World War II. The design of the ship is heavily modelled after a seafaring ship’s design, complete with a smooth hull on the bottom, mounted guns on the top, and even ‘rocket anchors’.
The uniforms of the characters are all lifted directly from naval designs, navigation is heavily reliant on radar, and they have an extended battle sequence with a ‘sub-space’ submarine (which slips beneath the waves, somehow). The explanation for all this is that the ship truly is the historical Yamato, sunk in WWII, exposed by dried-up oceans, and refitted for space travel. When they reach their destination, an ocean-covered planet, their ship finally looks at home.
Taking the idea one step further is the 2002 Disney classic Treasure Planet, which takes no prisoners in its adaptation of the Robert Louis Stevenson novel Treasure Island to the third dimension. It’s hard to pick where to start with this film, but the use of actual wooden sailing ships with actual sails is as good as any. The in-universe explanation for the tall ships is that they are powered by ‘solar sails’, but these bear little resemblance to their real-life counterparts. The protagonists are menaced by space pirates, they are able to walk on the decks without air supplies, and they literally take off from a ship’s dock.
Through all of this, it’s clear that the difficulties in understanding space can go both ways. On one hand, using nautical analogies is easier, allowing us to tell the stories we want to tell without letting the complicated physics get in the way. On the other hand, we can choose to play heavily with the analogies, since our lack of everyday experience with space travel does the hard work of suspending the viewer’s disbelief, allowing for ridiculous tales to exist where they otherwise would fall flat. And until such time as human spaceflight becomes an everyday experience, outer space will remain an infinite ocean, upon which all manner of tall tales (and tall ships) may be sailed.
Edited by Jessica Herrington