The space transportation company SpaceX launched its 22nd cargo resupply mission aboard the Cargo Dragon spacecraft to the International Space Station (ISS) for NASA on June 3. The spacecraft, that arrived at ISS on June 5, delivered more than 3,300 kg of research and supplies including some 5,000 water bears and 128 glow-in-the-dark bobtail squid.

The creatures will be part of scientific experiments which include studying how water bears tolerate space, the possible effects of microgravity on symbiotic relationships, analysing the formation of kidney stones, and more.

Why water bears and squids?

Tardigrades or water bears are microscopic (around 1mm long) 8-legged animals that can tolerate environments more extreme than most life forms can, both on Earth and in outer space. With the experiments, the researchers aim to study their hardiness close up, and possibly identify the genes that allow them to become so resilient. By learning how the water bears can survive in low gravity conditions, it would be possible to design better techniques to keep astronauts healthy on long-duration space missions.

Scientists also want to look at how microgravity conditions in space affect the relationship between the bobtail squid – which are also tiny (3 mm long) – and beneficial microbes. Microbes play a crucial role in the normal development of animal tissues and in maintaining human health. In the human body, microorganisms contribute to a variety of functions, including digestion, developing the immune system, and detoxifying harmful chemicals. A disruption in our relationship with these microbes can lead to disease. The research will allow scientists to have a better understanding of how beneficial microbes interact with animals when there is a lack of gravity. The findings will help space agencies develop better measures to protect astronauts from adverse host-microbe alterations on long-duration missions.

Launched in 1998, the International Space Station is a habitable artificial satellite in low Earth orbit. The floating laboratory is the largest single structure humans ever put in space to conduct experiments in microgravity and learn more about living and working in space.

Water bears can live without food or water for more than a decade. They can survive temperatures from zero to above the boiling point of water, pressure six times stronger than the deepest ocean trench, radiation hundreds of times higher than the fatal dose for a human, and the vacuum of space.

Bobtail squid have a special light organ inside the body that can be colonised by a species of luminescent bacteria. The squid can then use that bacteria to glow in the dark. The squid also have an immune system that is very similar to the type that humans have.