[dingensundso]

The prize is for an idea how to do it. Actually doing it will cost billions. You could enter your plan into the contest :)

[gumby]

Just doing the analysis for a plausible plan for a robot company would be expensive. My idea is at the "some guy in a pub" level :-).

[toomuchtodo]

Someone may have done the homework already. Doesn't hurt to try!

https://serdp-estcp.mil/newsitems/details/668f46ad-e481-4f5c...

https://apps.dtic.mil/sti/trecms/pdf/AD1204608.pdf

[gumby]

Just what can be decteded from the air, in shallow water. But could be a good start.

Unlike me they may have access to some capability to actually do it.