Why NASA keeps sending squid into space

If you watch enough sci-fi, you’re probably aware that aliens often look a lot like... humans. Whether to save money on prosthetics and makeup or make them more relatable, extraterrestrial beings, more often than not, walk on two legs, have a bilaterally symmetric body and sport a single head with a small number of eyes. Sometimes, all that really distinguishes them from us is green body paint.

But when writers need an alien that looks as un-human-like as possible, they often turn to a different group of organisms for inspiration: Cephalopods, the class of mollusks that includes octopuses, squid, and cuttlefish. This ancient, and at times, astonishingly intelligent, group of tentacled shapeshifters has inspired a diverse range of fictional beings, from H.P. Lovecraft’s Cthulhu to the 'heptapods' in the 2016 science fiction film Arrival to The Simpsons' Kang and Kodos.

Space squid, however, are more than a science fiction trope. Ten years ago, NASA actually sent squid into space. Last month, it did so again. As the space agency gears up to send humans back to the Moon and onward to Mars, the experiences of these spacefaring cephalopods may prove vital to keeping our astronauts healthy.

While in fiction, squid-like aliens range from roughly human-sized to big enough to swallow entire starships, the only cephalopod that has actually been to space — according to public records at least — is the bite-sized Hawaiian bobtail squid (Euprymna scolopes). A colorful calamari that inhabits warm, shallow coastal waters of the Hawaiian archipelago, the bobtail squid has a unique symbiotic relationship with the bioluminescent bacteria Vibrio fischeri. Inhabiting a specialized light organ within the squid's mantle cavity, vibrio cause their bobtail hosts to glow at night in a way that mimics downwelling starlight, preventing the squid from casting a shadow and making them harder for predators to spot.