It's amazing SF story. A cargo spaceship, propelled by a photon engine with a large reflective mirror ("sail"), visits the Jupiter system to deliver a cargo to a manned science station on Amalthea. Damaged by meteorites, the spaceship falls into Jupiter, but survives the pressure and floats in the dense atmosphere; the crew manage to work around the damaged mirror and start the main engine to escape Jupiter and finally reach Amalthea.