Russian cosmonaut Yury Malenchenko and US astronaut Edward Lu, as well as replacement crew members Alexander Kaleri and Michael Foale, trained under conditions of weightlessness to rehearse biomedical experiments they will conduct on the ISS, according to Russian biomedical specialists.

Their preparatory routine includes taking walks in the park and being kept in isolation during the ten days leading up to their departure.

The crew -- whose exact composition is to be determined by the State Commission Friday -- is to embark on its six-month mission to the ISS on Saturday at 0353 GMT.

The crew is to join Americans Kenneth Bowersox and Donald Pettit, and Russian Nikolai Budarin on the ISS, whose four-month mission started in December, but was extended after uncertainties following the Columbia disaster.

Since the Columbia space shuttle disintegrated on Febrary 1, killing all seven crew members, the US has suspended all NASA space shuttle missions to the ISS.

Russia's spacecraft are now the only means of transporting crew and support to the space station.

SPACE.WIRE