as "channeling", Van Tassel claimed to have established a new form of telepathic communication with these 'sources', utilizing a method which included both natural human abilities and the use of an allegedly advanced form of alien technology, rather than the more traditionally religious, non-technological, spiritual medium-based approach taken by many other early channelers of the era. Van Tassel maintained that the method he utilized was not a paranormal or metaphysical activity, but required being 'in resonance' with the messages being sent. It was an example of the application of an allegedly advanced extraterrestrial science, that anyone could implement with the proper training in meditation techniques. Giant Rock Space Conventions Van Tassel held weekly channeling sessions at Giant Rock at which people could "ask questions" and "channel answers" from extraterrestrials. According to Jerome Clark, these gatherings coalesced the scattered contactee subculture into a recognisable movement in January 1952. This led to the annual Giant Rock Spacecraft Convention organized by Van Tassel, which began in the spring of 1953 and continued for at least another 24 years. It marked Van Tassel's most important role in UFO history In 1959 up to 11,000 people attended these conventions and heard channeled messages claiming to come from space. Most of the well-known UFO contactees attended these conventions as speakers and channelers. Melton states that almost all of the 1950s contactees became involved in the two ecumenical structures founded by either Van Tassel or Gabriel Green. Most of the early messages Van Tassel claimed to have received from Ashtar were first presented to the public at these events. Van Tassel's early purported messages from Ashtar contained a great deal of apocalyptic material, which focused on concerns regarding the development of the soon-to-be-tested hydrogen bomb. It was claimed that on July 18, 1952, Ashtar entered the solar system as Commander in Chief of the Ashtar Galactic Command to warn humanity of the dangers of detonating the H-bomb, including the destruction of the planet. The messages stated the space command was determined that humans would not destroy the Earth through the wrong use of nuclear power and that the Command was helping the human race. Van Tassel also claimed that Ashtar had provided specific messages that he was expected to pass on to the U.S. federal government regarding the potential negative impacts of the proposed upcoming bomb tests. After the actual explosion of the H-bomb by the US