Is There a Limit to How Long Humans Can Survive in Space?

Two Russian cosmonauts broke the record for the longest duration stay on board the International Space Station .

The weightless environment causes loss of bone density, muscular atrophy, reduced volume of blood, decreased heart muscle functions, blurred vision, and disorientation.

A human mission to Mars would take roughly three years , according to NASA .

A Mars mission could expose astronauts to 0.7 sievert (Sv.Sv) of radiation with 1 Sv of radiation by increasing cancer risk by about 5% .

The record for the longest continuous stay in space is held by Russian cosmonaut Valeri Polyakov , who spent 437 days .

This is much higher than the typical radiation dose on the International Space Station (ISS), which is around 0.3 Sv for a six-month stay.

Spaceflight-Associated Neuro-Ocular Syndrome (SANS), cardiovascular disease, and potential nervous system damage may persist even after returning to Earth .

Mental health is also a concern, as extended isolation, confinement, and the distance from Earth can lead to stress, anxiety, depression, and cognitive decline.