Tardigrades on board of the STS-134 space flight

The joint ASI-AM DAMA mission supported a set of scientific experiments performed in short-duration microgravity, aboard the STS-134 Endeavour Space Shuttle docked to the International Space Station. During the 16 days of mission, BIOKIS payload (by Kayser Italia), hosted a multidisciplinary set of experiments in the field of biology and dosimetry. Among them, the TARDIKISS project investigated the responses of live desiccated tardigrades, multicellular heterotrophic organisms, to space stresses. In particular, specimens of Paramacrobiotus richtersi and Ramazzottius oberhaeuseri have been used. The experimental flight units were hosted into the Biokon, a standard transportable container by Kaiser Italia. In addition, a laboratory control sample was maintained in Modena laboratory for the duration of the flight, while a post-flight temperature control sample was exposed to the temperature profile experienced by tardigrades during the mission. The P. richtersi flight animals did not show differences in survival with regards to laboratory and temperature control animals, whereas in R. oberhaeuseri differences have been recorded between flight and temperature control samples. Specimens of P. richtersi from flight, laboratory and temperature control samples have been reared in lab. Flight females laid eggs with normal shape; several eggs have been able to hatch, and newborns exhibited, when adult, normal capability to reproduce. The comparative analysis of the antioxidant metabolism between flight and temperature control samples did not evidence significant differences between the two groups, with the exception of the gluthathione reductase activity in R. oberhaeuseri. These data confirm that tadigrades represent a useful animal tool for space research.