As the mission launches, Emma finds her mettle as commander tested by an onboard accident, a divided crew and a family emergency back on earth.

When a ship malfunction threatens the voyage before it's barely begun, Emma works with a wary Mishra on a high risk repair operation.

Ram endangers the lives of everyone on the Atlas, causing Emma to put herself in harms way; Matt must make a life-changing decision.

As Christmas approaches, the crew prepares to make their final calls home before communication grows spotty. Matt and Lex adjust to their new normal.

Emma's behavior becomes a cause for concern, Kwesi and Lu team up on a plant mystery, and Lex makes an impulsive decision with far-reaching consequences

A problem with Atlas's supply ship jeopardizes the mission and sparks questions about Emma's commitment to landing on Mars

Emotions run high as rapidly dwindling water rations on the Atlas leave the crew and Mission Control scrambling to find a fix before time runs out

With only hours to go before Atlas' planned touchdown on Mars, Emma is confronted with everything that could go wrong, while Lu receives new orders.