In Space

In much sf, space is a mere void to be crossed to reach a planet whereas, in several of Poul Anderson's works, space is an environment that his characters spend time in:

a spaceship attracts spores as they spread through asteroidal space (see here);

one spaceship tracks another through interstellar space (see here);

a Bussard ramjet accelerates at relativistic speeds through intergalactic space (see here);

Commonalty Ranger Daven Laure's self-aware spaceship, Jaccavrie, explores the opaque space of a globular cluster where glowing gas and dust conceal over a quarter of a million stars mere light-weeks or light-months apart.

I am still studying the "Cloud Universe" of Anderson's story, "Starfog." The crowded and clouded cluster is called "the Cloud Universe" because, when human beings who had been isolated for millennia within the cluster finally re-emerged into dark space, the difference between the two spatial environments was so complete that they thought that they had traveled between universes.

The cluster on its eccentric orbit has passed through the dense clouds near the galactic center twenty or thirty times, each time scooping up vast quantities of matter which then condense into several generations of giant stars.

It is impossible to navigate because:

the clouds of gas and dust absorb and diffuse the light even of supergiant stars;
the supergiants emit detectable neutrinos but so do many other sources;
the stellar proximity produces many magnetic effects;
many of the stars are doubles, triples or quadruples which revolve rapidly, thus twisting the force lines;
radiation keeps much of the interstellar medium in plasma form;
there is every kind of electromagnetic activity, synchrotron and betatron radiation and nuclear collision;
these and other unstated factors generate too much noise for any theoretically possible instrumentation;
inertial navigation would work at kinetic velocities but hyperdrive is necessary to cross parsecs and too rapid a change of gravitational potential between stars so close moving on such complicated paths would cause uncontollable perturbations;
the high cosmic ray background implies a high rate of nova and super-nova production which in turn indicates large numbers of navigational hazards like neutron stars, rogue planets, large meteoroids and thick dust banks.