The engine room of the Christa has changed and expanded throughout the series, much like the rest of the ship.
Copper Engine RoomEdit
This engine room in the first season , sometimes called "engineering", consists of a large engine fueled by a protomix called the "protomix master" and pillars that store ion particles. The ions are collected by the wings' solar sails through the ion glide; sometimes energy is sent to storage while other times energy is sent to the engine. Power is then sent to the thrusters and the ship is pushed along. Sending the ions from storage to the engines requires they be sent along the channels in the floor. The ship obtains ions from solar winds which can be gathered from stars and, as Cat remembers, the tails of comets. In "Desperately Seeking Suzee" the crew is trying to make the thrusters more effective.
The protomix master controls the hyperdrive (the faster-than-light drive) of the ship. Once the hyperdrive is shut down it takes twenty minutes to restart it. Crystals are on the control panels of this part of the engine. These crystals are used to start and shut down the hyperdrive as well as other things like reverse the polarity of the neutron flow. Thelma claims in "Nowhere Man" that the protomix master core has been acting erratically since the jump through The White Circle .
This room also contains the regulator console, which shows readouts of various processes such as radiation levels.
Silver Engine RoomEdit
In the second season we discover a different part of the engines. The seemingly massive section of the ship includes overhead fans, steel walkways, and large cylindrical chambers, among other things. The chambers- eight in total, arranged in two rows of four- allow access to multiple parts of the engine. The third chamber in the second row contains the energy crystal that focuses energy to the engine's thrusters. There is also a protomix transfer tube; in "Both Sides Now" they have to "dismantle the relays" in this tube in an attempt to get the engines fully offline.
When they crash on Kareesh 9 Suzee reports that a "protomix fuel line crack" has occurred. In the episode "Truth Hurts", Suzee goes out on her own to find a replacement crystal. Commander Goddard comes back from his exploration in the next episode and brings back the replacement power crystal.
The crystal that focuses power to the engines is a deutronium crystal, a reference to a fictional material used in Lost in Space. The planet that the crew crash-lands on in Space Cases, Kareesh 9, has naturally-occurring deutronium prismatic ore.