Jensen gained national attention when on April 26, 1980 he led a group of followers into fallout shelters, expecting an apocalyptic nuclear holocaust. He went on to predict that Halley's Comet would enter earth's orbit on April 29, 1986, and collide with the earth exactly one year later. With Jensen's approval, in the early 1990s his companion Neal Chase made a total of 18 disconfirmed prophecies that pertained to small-scale disasters that he claimed would lead step-by-step towards the Apocalypse, as well as dates for a nuclear attack on New York City by middle Eastern terrorists.