This is something like a mix
of end-of-world story, first contact, and a story of life in relatively early
space colonies in the solar system (still not truly self-sufficient in the long
run). An asteroid impact has caused a catastrophe on Earth. As far as the
2000 people scattered on various space colonies know, the Earth is no longer
habitable. The space colonies are in communication by radio and have one
remaining interplanetary spaceship capable of taking people or things from
colony to colony. They don't really have a ship that could land on Earth and
take off again to investigate or to scavenge.
For the time being, they have
supplies of food and replacement parts to last them a while. However, they
lack a real industrial base to make the electronics they will need when the
spare parts run out. And the fact they're still eating frozen foods from Earth
suggests they may not have what they need to feed themselves by producing their
own food. There is talk of building a rocket they can land on Earth and
bringing up needed supplies from warehouses, but at best that seems years away.
On titan, there are a number
of research stations and bases. While they still have spare parts, they're
sending out engineers to fix equipment at those various locations. At one
research station crewed by a single woman, we find activity in the "snow"
on the ground. Colored blobs move through it coming in response to certain
chemicals and vanishing when they encounter heat, radio waves or other
human-related energy emissions. She is beginning to think it is a sign of
life. But she's not yet ready to tell others what she's seen. An engineer
making a repair at the station figures something is going on, but the woman
doesn't want to let him in on the secret.
Woven together are threads
about how people stranded on space colonies might react, possible life on a
frozen moon like Titan, how people evolved on Earth might effect the ecology on
a world like Titan, etc.