Service endurance

Service Endurance is a term used to describe how long a vessel can remain in space without needing to be re-stocked, re-fueled, or otherwise re-supplied. It is generally measured in days. One day of service endurance means that all souls aboard (Crew, Passengers, etc.) can survive comfortably for 24 hours.

The Human-Day
Service endurance is calculated using the "Human Day," a formula which accounts for the resources consumed by one human aboard a ship in the span of 24 hours. One human-day requires:


 * 1) 2200 Calories of food supplies
 * 2) 2 Liters of Potable water
 * 3) 30 Liters of Grey Water
 * 4) 2200 Liters of Oxygen (at 1 atm)
 * 5) 100 Watts of usable electricity

Additionally, all of the following must be available to every crew and passenger:


 * Temperature which does not deviate from 15-25 degrees Celsius at any point
 * Access to a Restroom with running water
 * Reasonable accommodations which allow for sitting, standing, and laying down
 * Access to some form of emergency communication

Calculating Human-Days
Service Endurance can be calculated by first determining the number of Human-Days available to a ship. Calculations are made assuming that all tanks, stores, and reserves are full. The inventory with the least amount of human-days acts as the limiting factor. Use this resource when calculating the capacity of human days by dividing the total capacity of this inventory by its human-day requirement. This will result in the number of human days available to a ship.

Calculating Service Endurance
Service endurance can be calculated by dividing the number of human-days by the designed compliment of the vessel. This will return a number in days which is the service endurance.

Alternatively, if a mission or voyage requires a known number of days, the number of human-days could be divided by the length of the trip (in days) to return a maximum number of passengers for the voyage.