Berlin's Free University will begin recruiting guinea pigs in the coming week, it said.
Those selected will have to lie in bed practically without moving for eight weeks in the university medical department, so that researchers can observe effects similar to those on astronauts after a mission to Mars, 55 million kilometres (33 million miles) from Earth.
The reward: 5,000 euros (dollars) each.
Checks will be carried out on blood circulation, muscular distrophy and bone resistance to work out suitable training methods for a future manned Mars mission expected around 2014-15.
The research programme, starting next month, will be supervised by the Berlin Centre for Muscular Osteological Research in cooperation with the European Space Agency.