Just a couple of years ago, it seemed that space mining was inevitable. Analysts, tech visionaries and even renowned astrophysicist Neil deGrasse Tyson predicted that space mining was going to be big business. Space mining companies like Planetary Resources and Deep Space Industries backed by the likes of Google’s Larry Page and Eric Schmidt, cropped up to take advantage of the predicted payoff. After all, the holy grail of asteroids, known as 16 Psyche, had an estimated worth of $10,000 quadrillion. But fast forward to 2022, and humanity has yet to commercially mine even a single asteroid. CNBC spoke to two California startups, AstroForge and TransAstra, about how they are trying to make space mining a reality and the challenges they face.