Environmental Engineering Reference
In-Depth Information
1. The
reasons
for
providing
flight
autonomy
and
what
autonomous
capabilities have been developed to support these needs
2. The general time frame in which these capabilities have been developed
3. Possible future trends in flight autonomy development
While the material in this chapter relates particularly to science missions
(e.g., astronomical observatories, communications satellites, and satellites that
observe the surface of the earth), it should be applicable as well to the de-
velopment of missions that conduct robotic explorations of planets, moons,
asteroids, etc. Many of the philosophies, cultures, budgetary constraints, and
technologies span across all groups and agencies developing and flying any
type of uncrewed mission. Brought to the fore by crewed missions, however,
are numerous different considerations and constraints under which it makes
little sense to try to design crewed assets with autonomy. Consequently, crewed
missions are beyond the scope of this topic.
3.1 Reasons for Flight Autonomy
Flight autonomy capabilities typically are developed at NASA Goddard Space
Flight Center (GSFC) in order to
1. Satisfy mission objectives
2. Support spacecraft operations
3. Enable and facilitate ecient spacecraft operations
The object of a science mission, of course, is to perform the science for which
the spacecraft has been constructed in an accurate and ecient manner. As
the lifetime of a spacecraft (and the mission as a whole) is limited both by
onboard hardware robustness and budget allocations, it is crucially important
to optimize science data gathering as a function of time. And since all science
observations are not of equal importance, the optimization strategy cannot
be simply a matter of maximizing data bit capture per unit time. So a GSFC
science mission must be conducted in such a manner as to support ecient,
assembly line-like collection of data from routine, preplanned observations
while still permitting the flexibility to break away from a programmed plan
to exploit unforeseen (in the short term) opportunities to perform time-critical
measurements of ground-breaking significance.
Reconciling these inherently contradictory goals requires a subtle inter-
play between flight and ground systems, with carefully traded allocations of
responsibility in the areas of schedule planning and execution. Typically, the
superior computing power of the ground system is utilized to optimize long-
and medium-range planning solutions, while the quick responsiveness of the
flight system is used to analyze and react to realtime issues. In the next
section, we will discuss what autonomous capabilities have been developed to
support the flight system's role, and how they enable higher levels of eciency
and flexibility.
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