Environmental Engineering Reference
In-Depth Information
To achieve all of its mission objectives, a spacecraft must maintain near-
nominal performance over a minimum lifetime. This day-to-day maintenance
effort implies the presence of an onboard infrastructure supporting routine
activities such as command processing and resource management, as well
as performance of these activities themselves. Furthermore, since a space-
craft's lifetime may be compromised by onboard hardware failures, latent
software bugs, and errors introduced operationally by the ground system, the
infrastructure must include the capability to safeguard the spacecraft against
further damage or loss from these causes. Therefore, the flight system must
routinely monitor spacecraft health and, on detection of an anomaly, either
fix the problem immediately so that the mission can continue, or configure
the spacecraft so that (at a minimum) it remains in a benign, recoverable
state until the problem can be analyzed and solved by operations support
personnel.
In addition, to accomplish its mission objectives as economically as pos-
sible, the entire system (spacecraft platform and payload, flight data system,
and ground system) must be developed not only within increasingly strin-
gent cost constraints, but must also be designed so as to make the conduct
of the mission as inexpensive as possible over the entire mission lifetime. To
achieve this, the flight system must be designed to carry out spacecraft activi-
ties accurately, eciently, and safely, while at the same time performing these
activities in a manner that reduces the complexity and mission-uniqueness of
the flight and ground system, and facilitates the reduction of FOT stang
during routine operations.
In the following sections, each of these three major drivers for flight au-
tonomy will be examined relative to more specific objectives or goals to be
achieved and the means by which these goals are achieved. A summary of this
3.1.1 Satisfying Mission Objectives
GSFC spacecraft mission objectives can be grouped in three major classifica-
tions:
1.
Science execution
2.
Resource management
3.
Health and Safety maintenance
Put briefly, these objectives encompass what must be done to perform science
eciently, what onboard resources must be managed in support of science
execution, and what precautions must be taken to safeguard the spacecraft
while these activities are being performed. The flight system has a critical
1
In this table and frequently in this topic, the simple term “ground” will be
used to mean “ground system” or “ground operations” in reference to personnel
and spacecraft control capabilities on earth.
