The demise of the Russian space station, Mir, has closed an important chapter on research conducted by Swiss scientists.
For the last seven years, a team at the Federal Institute of Technology in Zurich has collaborated with the European Space Agency (ESA) and NASA to measure the impact of weightlessness on human bones and muscles.
Since 1995, their Bone Stiffness Measuring Device - a collaborative venture between ESA and the Russians - has monitored the stiffness of bones during missions on Mir.
"Microgravity or zerogravity can lead to atrophy of the whole body and especially of the bones and muscles," Professor Edgar Stüssi, head of the Laboratory for Biomechanics, told swissinfo.
"The Russians knew what sort of countermeasures they had to take and we monitored those countermeasures to see if they were successful.
"Long-term flights to Mars are inconceivable until we have solved this problem. Astronauts who come back to earth can't survive if they've lost 60 per cent of their bone mass. Gravity would break the bones."
Back on earth, the Zurich team's work on osteoporosis has benefited from the data collected on Mir.
Another machine from Zurich, the Torque Velocity Dynamometer, employed on the American space shuttle, examines changes in muscle performance.
Dozens of European science experiments were carried out on Mir thanks to the collaboration between ESA and Russia.
Mir's 15-year mission ended on Friday when the 135 tonne station crashed into the southern Pacific Ocean. Mir was plagued by technical problems but the station lasted three times longer than originally planned.
Over the years, Mir has circled the earth about 88,000 times, travelling 3.6 billion kilometres.
by Vincent Landon