Mission to Mercury

The manned expedition to Mercury is complicated by the fact that strong solar radiation makes communication with Earth impossible. U.N.E.X.A. decide that telepathy may be the answer. Telepathic twins Gill and Gail volunteer; one accompanying Chris Godfrey and the crew on the mission; the other remaining on Earth. As they near their objective, Gail notices increasingly disruptive personality changes in the crew caused by the radiation, their only chance of survival is to land on the 'dark' side of the planet; however the near absolute zero conditions lead to massive heat-loss. Can they be rescued before freezing to death...