Washington - Long journeys into deep space, including a mission to Mars, could expose astronauts to levels of cosmic radiation harmful to the brain and accelerate Alzheimer's disease, said US research on Monday.

The Nasa-funded study involved bombarding mice with varied radiation doses, including levels comparable to what voyagers would experience during a mission to Mars, and seeing how the animals managed to recall objects or locations.

Mice that were exposed to radiation were far more likely to fail those tasks - suggesting neurological impairment earlier than such symptoms typically appear.

"Galactic cosmic radiation poses a significant threat to future astronauts," said Michael O'Banion, a professor at the University of Rochester Medical Centre and senior author of the study published in scientific journal Plos One.

"This study shows for the first time that exposure to radiation levels equivalent to a mission to Mars could produce cognitive problems and speed up changes in the brain that are associated with Alzheimer's disease."

So - in other words, when you get to Mars or wherever you forgot what you went there for!

Actually maybe there are galactic rays in my house as I often arrive at a room and wonder "Why am I here?".


Kevin