A Russian man has broken the record for the longest (cumulative) stay in space, having been in orbit for a massive 748 days, this Tuesday. Cosmonaut Sergei Krikalev is currently onboard the International Space Station, but has also spent time aboard Mir during his career.

Krikalev was born in Leningrad, now known as St Petersburg, in 1958. He was selected as a cosmonaut in 1985 and began his training in 1988. His first extended mission in space was a stay aboard Mir in 1988.

Extended periods in low or zero gravity take their toll on the human body: bones begin to decalcify as they experience less stress, and muscles atrophy, also as a result of disuse. The body also produces fewer red blood cells in the absence of gravity, and the immune system weakens, although scientists are not sure why this should happen.

Most of these changes can be reversed upon return to Earth, although while in space, astro and cosmonauts work hard to minimise their deterioration. ®

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