In April 2018, the B612 Foundation reported "It’s 100 per cent certain we’ll be hit a devastating asteroid, but we’re not 100 per cent certain when." Also in 2018, physicist Stephen Hawking, in his final book "Brief Answers to the Big Questions", considered an asteroid collision to be the biggest threat to the planet. In June 2018, the US National Science and Technology Council warned that America is unprepared for an asteroid impact event, and has developed and released the ""National Near-Earth Object Preparedness Strategy Action Plan"" to better prepare. According to expert testimony in the United States Congress in 2013, NASA would require at least five years of preparation before a mission to intercept an asteroid could be launched.