11.1 Life Support and Environmental Control

The hardware and consumables required for maintaining a habitable environment are distributed about key areas aboard Deep Space 9 and service all accessible volumes. All humanoid life-forms need water, foodstuffs, and breathing gas for basic survival; within an artificial environment, one also needs the systems needed to supply and recycle them. The significant environmental factors to be stabilized for comfortable living are pressure, temperature, humidity, and radiation, and to a lesser degree, gravity. Other related factors include the detection and elimination of contaminants in the biological intake, exposure to EM fields, and medical intervention in adverse environmental conditions.

Aboard Deep Space 9, the diverse nature of the resident population requires an equally diverse set of controllable environments, with common areas of the station accessible to a baseline standard for oxygen-breathing races (see 11.2).

Groupings of life-support subsystems, such as gas and liquids tanks and airflow venturis, are organized into primary, secondary, and reserve life-support facilities aboard the station. Most groupings are interconnected for maximum options in rerouting consumables in both benign and crisis conditions. Some 2,650 kilometers of additional ducting and fluid piping was added by Starfleet in 2369 to handle the redistributions. The secondary and reserve systems are not truly independent loops, but do provide backup valving and pumping capability in the event the primary systems falter.

Atmospheric chemistry subsystems and airflow handlers are located on Levels 1, 3, 6, 11, 15, 24, 30, and 36. Fluid storage and mixing tanks, plus associated transfer pumps, are located on Levels 1, 3, 8, 11, 15, 26, and 32. Multimode sensors for the total environmental system are located on all station levels and report to both local system controllers and the central computer cores for homeostasis command responses. Emergency situations that likely will overwhelm automatic responses will trigger crew actions with appropriate hardware, as in fire-fighting situations, hull breaches, and so on. Emergency supplies of stored breathing gases, foodstuffs, and protective garments are distributed about the station (see 13.1), independent of the consumables distribution network.

The general Starfleet requirements for Deep Space 9 life support are as follows:

• Environmental specifications. Environmental systems to conform to SFRA-standard 104.12 for class-M compatible oxygen-breathing personnel. All primary systems to be doubly redundant. Atmospheric and fluid transfer systems to be maintained with 4,850-hour MTBF components.
• Population limit. Ability to support up to 25,000 total crew, residential, and transient personnel.
• Environmental range. Facilities to support class-M environmental range in all individual living quarters, provisions for 25 percent of quarters to support class-H, -K, and -L environmental conditions. Transient facilities to include an additional 3 percent class-B, -N, and -C environments.
• Radiation protection. All habitable volumes to be protected to SFRA-standard 354.32(c, d) levels for RF, subspace, and nuclear EM. Subspace flux differential to be maintained within 0.02 millicochranes. All primary environmental shielding systems to be doubly redundant.