Roscosmos filed an official request to the U.S. side to participate in the investigation, but they refused Moscow - Ria Novosti NASA has refused to participate in an experiment designed to show if U.S. radars could have had an impact on Russia’s troubled Phobos-Grunt Mars probe, the deputy head of the country’s space agency, Roscosmos, Anatoly Shylov said on Thursday. “Roscosmos filed an official request to the U.S. side to participate in the investigation, but they refused,” Shylov said. The official also said that the government commission inquiry into the cause of the probe’s crash had issued a final report with the results of the investigation. It is expected to be published next week. Among the possible causes of the Phobos-Grunt probe’s crash, investigators said interference from the U.S. radar installed on the Marshall Islands in the Pacific Ocean could have had an impact. Scientists however dismissed the idea, saying that the U.S. radar theory is cover up to hide some people’s mistakes. Phobos-Grunt, Russia\'s most ambitious planetary mission in decades was launched on November 9 but it was lost due to propulsion failure and fell back to Earth mid-January. Soon after the failed launch, the Russian space agency Roscosmos said a rocket motor should have started to push the probe into higher orbit but it failed to fire for unknown reasons. According to NASA, Russia failed in all 17 of its attempts to study the Red Planet close-up since 1960. The most recent failure before November 2011 was in 1996, when Russia lost its Mars-96 orbiter during launch.