I had no idea. I usually put going underground off until after I've fully scanned the surface (always use the Fast-Scanning game rule).
Although... I HAVE noticed that researching Breakthroughs that reveal rich deposits of metal/rare metals/water, they tend to appear on all maps, including asteroids.
This has not always been a bad thing... although it sometimes makes me more reluctant to abandon an asteroid for a fresh new one. :P

Huzzah no more borked deposits!