Ethan Thornton, a 21-year-old founder of Mach Industries, has secured over $80 million as Sequoia Capital's first defense tech investment. After a hydrogen gun prototype explosion injured a team member, Thornton emphasized the lack of safety resources. Following this incident, Mach paused operations until securing funding from Sequoia. The startup has since pivoted from hydrogen to developing advanced weapons, including a cruise missile and a bomb named 'Glide.' With a U.S. Army contract in hand, Mach is also planning a decentralized factory network, showcasing its strong relationship with the federal government.