In article , Hop David wrote:

A large number of small probes manufactured on an assembly line would
have a small unit cost. Small enough probes could be bundled two or
three (maybe more) per launch, reducing launch costs. These could show
us where ice and other resources are on the moon and NEOs.

You would soon run into the limits of the DSN.

DSN?

Deep Space Network. http://deepspace.jpl.nasa.gov/dsn/

Sooner or later, the more probes you put out - and, especially, the more
small probes, because they tend to have weaker signals - you're going to
run out of facilities to get information back.
--
-Andrew Gray