A method of controlling environmental characteristics in an enclosed space; the method comprising: - receiving at a first time a first input indicative of a selection of a circadian setting; - in response to the first input indicative of the selection of the circadian setting, providing signals by a control subsystem which is communicatively coupled to cause a plurality of illumination sources to emit artificial illumination at a number of levels and a number of wavelengths and which is communicatively coupled to cause at least one actuator to control at least a level of natural illumination received into the enclosed space via one or more windows from an external source of illumination such that a combination of the artificial and the natural illumination varies over a first period of time according to a circadian pattern, the circadian pattern at least approximately matching changes in illumination level and color temperature of naturally occurring illumination of at least one defined latitude over the first period of time; - receiving at a second time a second input indicative of a selection of a first non-circadian setting; and - in response to the second input indicative of the selection of the first non-circadian setting, providing signals by the control subsystem to cause a plurality of illumination sources to emit artificial illumination at a number of levels and a number of wavelengths and to cause at least one actuator to control at least a level of natural illumination received into the enclosed space via one or more windows from an external source of illumination such that a combination of the artificial and the natural illumination does not vary over a second period of time according to the circadian pattern; and - receiving, via presenting a graphical user interface to a facility personnel, an identifier via the graphical user interface, which identifies an occupant of the enclosed space at a fourth time, and a fourth input indicative of a selection of a travel adjustment setting; - in response to the fourth input indicative of the travel adjustment setting: determining a travel adjustment illumination pattern based at least in part on a geographic location from where the occupant of the enclosed space originated to accommodate a change in circadian rhythm due to travel by the occupant; and - providing signals by the control subsystem to cause the illumination sources to emit artificial illumination at the levels and the wavelengths and to cause the at least one actuator to control at least the level of natural illumination received into the enclosed space via the one or more windows such that the combination of the artificial and the natural illumination achieves the determined travel adjustment illumination pattern in the enclosed space. - receiving at a first time a first input indicative of a selection of a circadian setting; - in response to the first input indicative of the selection of the circadian setting, providing signals by a control subsystem which is communicatively coupled to cause a plurality of illumination sources to emit artificial illumination at a number of levels and a number of wavelengths and which is communicatively coupled to cause at least one actuator to control at least a level of natural illumination received into the enclosed space via one or more windows from an external source of illumination such that a combination of the artificial and the natural illumination varies over a first period of time according to a circadian pattern, the circadian pattern at least approximately matching changes in illumination level and color temperature of naturally occurring illumination of at least one defined latitude over the first period of time; - receiving at a second time a second input indicative of a selection of a first non-circadian setting; and - in response to the second input indicative of the selection of the first non-circadian setting, providing signals by the control subsystem to cause a plurality of illumination sources to emit artificial illumination at a number of levels and a number of wavelengths and to cause at least one actuator to control at least a level of natural illumination received into the enclosed space via one or more windows from an external source of illumination such that a combination of the artificial and the natural illumination does not vary over a second period of time according to the circadian pattern; and - receiving, via presenting a graphical user interface to a facility personnel, an identifier via the graphical user interface, which identifies an occupant of the enclosed space at a fourth time, and a fourth input indicative of a selection of a travel adjustment setting; - in response to the fourth input indicative of the travel adjustment setting: determining a travel adjustment illumination pattern based at least in part on a geographic location from where the occupant of the enclosed space originated to accommodate a change in circadian rhythm due to travel by the occupant; and - providing signals by the control subsystem to cause the illumination sources to emit artificial illumination at the levels and the wavelengths and to cause the at least one actuator to control at least the level of natural illumination received into the enclosed space via the one or more windows such that the combination of the artificial and the natural illumination achieves the determined travel adjustment illumination pattern in the enclosed space.