Per the instructions, click and hold to mine.
Clicking, clicking and holding, landing on, flying nearby, etc all do nothing to asteroids on Android/DuckDuckGo browser.
Can't get far in an incremental game when you can't acquire currency.
I can lock on top of or next to an asteroid, but either way holding down (or clicking) on the asteroid doesn't do any mining.
I agree that precision clicking on a phone/tablet with a game running in real time can get irritating, and auto lasers sound like a good way around that, but at present screen visibility is a moot issue. No mining is possible, at all, in the OS/Browser combination I'm working with.
Did you test mobile functioning with a computer via a compatibility mode? Most languages have different calls for different HID inputs, it's possible the mining function(s) are looking for mouse input specifically, which a test on the computer might miss.