LIGHT FLASH OBSERVATION IN SPACE - EXPERIMENT ELFO

We present the scientific case for a thorough investigation of light f lashes (LFs) observed by astronauts since early lunar missions. A comp lete assessment of the phenomenon is achieved through a sophisticated helmet-like silicon detector put on the head of the astronauts. This d evice will be able to identify cosmic-ray nuclei and measure their ene rgy and trajectory, is order to correlate each light flash with the si ngle particle likely to produce this effect. In addition, a study of p recise time-correlation between cosmic-ray impinging on the head of th e cosmonaut and functions in the Central Nervous System (CNS) is addre ssed via investigation of the concurrent spontaneous bioelectrical cor tical activity in the cortex (EEG) and of retinal and cortical respons es at luminance and contrast stimuli (ERG,VEP). This joint knowledge w ill help to identify the intel action mechanism behind light flashes, and to build better models of the visual sensory processes. The silico n detector will also give information for a more accurate biological d osimetry by the knowledge of the relative fluences of the different pa rticles: a contribution for a deeper understanding of the physiologica l modifications during long manned missions. The proposed apparatus is supposed to work on-board of the Russian MIR Space Station or, later, on board of the International Space Station ALPHA.