The extractor is the first thing the chain asks for that cannot be paid for
out of a single hold. Every hull carries twenty and the fleet is small; the
mothership is where anything larger than one trip has to accumulate, and
nothing in the game had ever said so.
A deposit quest sits before it now, asking for sixty ore BANKED - which is
a different question from the one GOAL_RESOURCE answers, since that counts
the hold too, and the hold being too small is the whole point. So it needed
a goal kind of its own.
Sixty is three full holds, so it cannot be satisfied by accident on the way
past, and it leaves enough behind to actually buy the extractor afterwards.