Patterns in Crew-Initiated Photography of Earth from the ISS—
Is Earth Observation a Salutogenic Experience?In response to this supposition, the composite variable of days available, or
general availability, was used to reflect workload on the ISS more accurately. This
composite took into account whether activity on the Station was extraordinary,
whether it was a weekend, and whether a particular day was considered an off or
partial-duty day or a regular-duty day. General availability was thus a more realistic
representation of days with crewmember free time.
This post hoc hypothesis was supported. Regarding the taking of images, more
self-initiated images were taken when crewmember schedules allowed (see figure
2). Crewmembers were less likely to take self-initiated images on a Saturday, for
example, if they were also preparing for an EVA. In more statistical terms, general
availability was associated with whether self-initiated images were taken (t = 4.37,
p < .01), conditional upon the intercept and after controlling for time on the
Station. Additionally, later in the mission, crewmembers became even more likely
to take self-initiated images when their schedules allowed, indicating that general
availability predicted differentially as the mission progressed (t = 2.26, p = .02).
Regarding the number of images taken, the longer crewmembers had available
time, the more images they took. In more statistical terms, general availability pre-
dicted the number of self-initiated images taken (t = 2.10, p = .02) after controlling
for the intercept and time on the Station. Further, crewmembers took just as many
images when they had time available at the beginning of the mission as at the end
of the mission. In other words, general availability did not differentially predict over
the length of the mission (t = –1.22, ns).
Hypothesis 3: Geographic interest. Hypothesis 3 stated that crewmembers
would take more self-initiated images of areas that were of personal interest to
them.^23 This hypothesis was not supported by the data (χ^2 (df = 1) = 1.14, ns).
Crewmembers were no more likely to take self-initiated images of geographic areas
of personal interest to them than they were to take any other self-initiated images.
The fidelity of the measure of areas of personal interest is questionable, though. The
geographic areas of interest were determined by our survey methods rather than by
direct reports from crewmembers themselves.
- Due to limitations in the GLIMMIX procedure, a model fitting geographic interest could
not converge. As an alternative, the GENMOD procedure was used. Given that GLIMMIX
uses the GENMOD procedure to fit generalized linear models when random effects are absent,
this change in statistical procedure is not significant.