ABSTRACT

The question has been raised whether living organisms can reproduce in space. In other words, are mating, fertilization, embryonic development and delivery possible in the absence of gravity? This is important because humans may one day undertake long-term space missions. These questions are not easily answered though it has been known for some time that certain species can reproduce in microgravity. This was true of Drosophila fruit flies used in genetic experiments aboard the first satellites. Later, the Spanish biologist R.Marco observed during a Spacelab mission that although oocyte production was normal, there were less embryos and larvae hatching and developing from these oocytes. Other experiments performed aboard Skylab-3 and on the Apollo-Soyuz mission showed that fish eggs from Fundulus killifish developed with important abnormalities in different systems or organs like the cardiovascular and visual systems, and the vestibular apparatus. However, any gravityinduced effects are likely to go undetected since they would only occur during the first steps of embryonic development before compensatory mechanisms came into play to regulate them. In other words, no answers can be given without having the biological material and equipment necessary for studying the influence of gravity on fertilization and the first steps of egg and embryo development. New space experiments have been performed with this objective on amphibians, sea urchins and fish eggs.