A rocket blasted into space today carrying an unmanned probe on a six-month mission to Mars that is designed to help prepare for a manned voyage to the planet. Soviet television broke into its evening news program ``Vremya'' for a live broadcast of the 9:38 p.m. launch from the Baikonur space center in the Soviet Central Asian republic of Kazakhstan. A 180-foot-tall Proton rocket capped by the probe, Phobos I, erupted in white and gray smoke and orange and blue flames. The newscast switched to the Soviet Mission Control Center outside Moscow, which reported the spacecraft's flight was normal. More than a dozen nations are participating in the mission to swoop close to the surface of Mars' moon, Phobos, and drop probes onto the small, potato-shaped moon that scientists say may hold clues to how the universe was formed. A second satellite, Phobos II, is scheduled to blast off July 12. The satellites will enter Mars' gravity in January and begin a three-month remote study of the surface and atmosphere of Mars. After that, scientists said, they will draw closer to Phobos and drop descent vehicles carrying laser, ionic and radar equipment to help determine the internal structure and composition of the moon. The probes are expected to be sent to Phobos in about April of next year, according to Roald Sagdeyev, director of the Soviet Academy of Sciences' Space Research Institute. Soviet space scientists said Phobos is an important step toward a manned flight to Mars, which they hope can take place in the early 21st century. Officials including Soviet leader Mikhail S. Gorbachev have proposed that the United States take part in the mission. ``First, it is necessary to draw up a more accurate map of the Mars surface in order to choose a place for the future landing,'' said Vyacheslav Balebanov, a deputy to Sagdeyev. ``Then, it is necessary to study the climate and soil characteristics and find out whether oxygen should be taken from Earth, or whther it can be gotten directly on the planet. The study of Mars renewed under the Phobos program should provide answers to those questions,'' he said in an interview with the newspaper Sovietskaya Rossiya. Also participating in the project are Austria, Bulgaria, Hungary, East Germany, Ireland, Poland, Finland, France, West Germany, Czechoslovakia, Switzerland, Sweden, the United States and the European Space Agency. The Deep Space Network of the U.S. National Aeronautics and Space Administration will provide tracking data to permit two 100-pound landers to reach Phobos, and then will begin to track the Martian moon precisely using antennas in California, Spain and Australia, and a Soviet radio telescope in the Crimea.