Why ca n't humans stay in spaceflight for longer ?
Cell - Cell Interaction of Monocytes and T-Lymphocytes in microgravity - MIA IMMUNO Nerve Growth Factor ( NGF ) Neuroendocrine and immune responses in humans during and after long term stay at ISS ( IMMUNO ) Role of weightlessness on actin metabolism in mammalian cells ( ACTIN ) Sympathoadrenal activity in humans during spaceflight ( SYMPATHO )