Twelve women have spent two months in bed with their feet higher than their head - all in the name of science.
The volunteers underwent more than 180 tests while in bed
Designed to recreate the effects of weightlessness, the experiment was run by the European Space Agency in France.
The women, volunteers from Switzerland, Scotland, Finland and France, had to carry out all daily activities in their bed, tilted back at a six degree angle.
Now back on their feet for final tests, the women said they were proud to have helped future female cosmonauts.
The European Space Agency (Esa) hopes the results of the study will help scientists anticipate medical problems that may arise as space missions go further and last longer.
The women underwent more than 180 tests, and were kept under constant video scrutiny before being allowed out of bed on 30 November.
They were split into three groups, one fed a special diet, one asked to carry out certain muscular exercises and the other used as a control group.
During the 60-day "bed-rest" stint they were allowed books, TV, music and internet access but had face-to-face contact only with medical staff.
Their rehabilitation will come to an end next week, after living in the MEDES medical research centre in Toulouse, France, for 101 days in total, including three weeks at either end of the bed-rest.
Doctors predicted the physical effects would include a swollen face, blocked nose, twinges and aches, muscle wastage and loss of bone mass.
The volunteers, who had to be aged between 25 and 40, in good health and fluent in English or French, were paid 15,200 euros (£10,000) for their participation.
Stephanie Gacher, 31, told a press conference she was "proud" to have come within touching distance of her childhood dream of going into space.
"I gave a part of myself for future female cosmonauts," said Martine Riou, quoted by the AFP news agency.
Another group of 12 completed the bed-rest stint earlier this year.
Twelve scientific teams from 11 different countries are involved in the study. They are expected to start publishing their findings next year.