Redemption Cairn

Sands has proof of Avery's poor piloting ability during the landing on Europa, when he is forced to take over to prevent her from crashing the Minos.

One day, he and Avery return from gathering food to find Henshaw shot dead and Coretti wounded by Gogrol.

The biologist forces the two pilots into the next valley and then crosses back over the airless ridge connecting them wearing an air helmet.

Avery then tells Sands the real purpose of the mission: Captain Gunderson of the Hera had discovered vast deposits of protactinium on the previous expedition, and worked out a process for using it as a power source.

In Weinbaum's Solar System, in keeping with the then-current "near-collision" hypothesis of planetary formation, Jupiter radiates enough heat to create Earth-like environments on the Galilean moons.

Europa is airless except for a depression on the Jupiter-facing side of the tidally locked moon, which holds a thin, but breathable atmosphere.