Defective Russian Mars probe Fobos-Grunt returned to Earth on Sunday, landing in the Pacific Ocean, dpa cited Interfax news agency as reporting. Debris from the 13.5-ton space vehicle fell into the ocean at around 1745 GMT, said Russian Defence Ministry spokesman Alexei Zolotukhin. Russian space experts, monitoring the probe's descent, kept adjusting its predicted trajectory, calculating that chances were very slim of it hitting an inhabited area. At one point it was expected to land to the west of the Argentinian city of Rosario. The Fobos-Grunt probe had circled Earth in a decaying orbit, refusing to respond to ground commands from mid-December, after its interplanetary engines failed to ignite following its launch on November 9. More than 80 per cent of the spaceship's mass was rocket fuel, which was expected to burn up passing through the Earth's atmosphere, but officials at national space agency Rocosmos had said some 20-30 pieces of the probe could survive re-entry. The 150-million-dollar Fobos-Grunt project had been intended to boost the prestige of the Russian space programme, 15 years after the country's last interplanetary mission.