Another thing that occurred to me after watching some of their videos - how do they plan to control rate of penetration?

Their radiation head thing has to be a certain distance from the rock face it's cutting / vaporizing, but it isn't actually touching anything. So how do they know how fast they're actually vaporizing more hole and how fast to advance?

I'm sure you know this, but for the rest of the audience, conventional drilling rigs use the measured weight of the drillstring to determine how much weight is on the bit and how fast to advance. I don't see any good way for these guys to do anything like that.