MOSCOW, May 16: Crew aboard the Mir space station will carry out an experiment designed to help develop drugs to fight cancer and immune system diseases, a space official said.Oleg Mitichkin, head of the medico-biological division at the Energiya Space Research Corporation said a Progress M-39 cargo ship to be launched soon will carry a special system for conducting the experiment.The crystals provide a model by which molecules similar to those which fight cancer and immune system diseases in the human body can be grown. The experiment is scheduled to start immediately after the supply craft docks with Mir on May 17. Former presidential aide Yuri Baturin will wind up the experiment during his stay on Mir in August and will bring the experimental materials back to earth with him.