Environmental Engineering Reference
In-Depth Information
8
Autonomic Systems
NASA requires many of its future missions (spacecraft, rovers, constellations/
swarms of spacecraft, etc.) to possess greater capabilities to operate on their
own with minimal human intervention or guidance [
180
-
182
]. Autonomy
essentially describes independent activity toward goal achievement, but space-
system autonomy alone is not sucient to satisfy the requirement. Autonomic-
ity, the quality that enables a system to handle effects upon its own internal
subsystems and their interactions when those effects correspond to risks of
damage or impaired function, is the further ingredient of space assets that
will become more essential in future advanced space-science and exploration
missions. Absent autonomicity, a spacecraft or other asset in a harsh environ-
ment, will be vulnerable to many environmental effects: without autonomic
responses, the spacecraft's performance will degrade, or the spacecraft will
be unable to recover from faults. Ensuring that exploration spacecraft have
autonomic properties will increase the survivability, and therefore, their likeli-
hood of success. In short, as missions increasingly incorporate autonomy (self-
governing of their own goals), there is a strong case to be made that this needs
to be extended to include autonomicity (mission self-management [
160
]). This
chapter describes the emerging autonomic paradigm, related research, and
programmatic initiatives, and highlights technology transfer issues.
8.1 Overview of Autonomic Systems
Autonomic Systems, as the name suggests, relates to a metaphor based on
biology. The autonomic nervous system (ANS) within the body is central to
a substantial amount of nonconscious activity. The ANS allows us as indi-
viduals to proceed with higher level activities in our daily lives [
63
] without
having to concentrate on such things as heartbeat rate, breathing rate, reflex
reactions upon touching a sharp or hot object, and so on [
42
,
146
,
161
]. The
aim of using this metaphor is to express the vision of something similar to be
achieved in computing. This vision is for the creation of the self-management
