Denizens of Jupiter's Atmosphere

Question

I don't remember the title or author.

It was about an expedition in Jupiter's atmosphere, and the people in their spacecraft crash onto a life form that resembled a giant whale or something. The creature turned out to be intelligent, and had 2 brains- one slept while the other kept the body going. They can't launch without killing the creature and something happens in the end where an eruption on the planet surface far below sends some kind of mouth-like creatures flying into the atmosphere eating everything in their path.

I read the story probably 20 years ago, so some of the details may be a bit fuzzy.

Answer 1

I believe you are thinking of Saturn Rukh by Bob forward: Wikipedia link. Quoting:

In an unspecified time in the future, a multi-national consortium sends a team of six astronauts (each with the chance of earning a billion dollars if they complete their mission properly) to Saturn to establish a factory that mines helium for the production of precious "meta" (stabilized metastable helium), a powerful rocket fuel, in the planet's upper atmosphere. With only enough "meta" fuel to get them to Saturn, failure will cost them their lives. And all too soon the crew of astronauts crash-lands on a surface, which is actually the back of an enormous alien life-form they dub the Rukh, a 4-kilometer-long, bizarre sting-ray-shaped creature that "swims" through Saturn's gaseous upper atmosphere and has two brains, both male and female. When part of their apparatus is swallowed by one of these giant birdlike beings, the crew needs to find a way to communicate and to be able to cooperate with the Rukhs so that they may survive.