A training accident spurs a national debate about women astronauts.

Ed and the crew change Apollo 15's landing site after lunar ice is detected.

A crisis in space puts the Apollo 24 and 25 crews in peril.

Ed handles a trespasser. Ellen and Deke chart a new course without Mission Control.

Margo must lead a seemingly impossible mission. Danielle wants to return to the moon. Gordo grapples with life on Earth.

Gordo returns to space. Molly faces an upsetting new reality. Aleida confronts her first major hurdle at work.

The rivalry between American astronauts and Soviet cosmonauts intensifies as last-minute changes impact the Pathfinder mission plan.

The race to land first on Mars brings together unexpected allies.