Environmental Engineering Reference
In-Depth Information
the thrusters to damp out unusually high booster separation rates. So, some
access to and control of thruster firing by the backbone is critical.
6.1.5 Electrical Power Management
Even in conventional FSW designs, electrical power management is somewhat
isolated from other FSW functionality to protect against “collateral” damage
in the event of a processor problem or software bug. Some functionality within
the electrical power subsystem may even be hard-wired. Although managing
SI requests for use of electrical power might rightly reside inside a Remote
Agent, management of the most critical spacecraft power resource must reside
within the FSW backbone.
6.1.6 Thermal Management
As with electrical power management, thermal management in conventional
FSW designs is already set apart from other FSW functionality for the same
reasons. Also for the same reasons, it also must reside within the FSW
backbone.
6.1.7 Health and Safety Communications
Although nominal communications should be highly autonomous to support
ecient downlink of the massive quantities of data generated by modern SIs,
in the event of a spacecraft emergency, ground controllers must be guaran-
teed direct access to any information stored onboard to help them understand
and correct any problem. They must also be capable of sending commands to
any hardware element involved in the resolution of the crisis. To support
these fundamental mission requirements, especially during the early post-
launch checkout phase, full ground command uplink capability (probably via
a low volume omni antenna) must be provided both through the FSW back-
bone and through a command and data handling (C&DH) uplink card in the
event the main processor(s) is (are) down. Low rate downlink through an omni
must also be provided to guarantee the ground's reception of key status data,
as well as (if necessary) more detailed engineering data stored just prior to
the onset of a problem.
6.1.8 Basic Fault Detection and Correction
Just as all processing necessary for maintaining the spacecraft in safemode
must be contained within the FSW backbone, the key functionality associ-
ated with transition into safemode must also reside within the backbone. In
particular, basic FDC limit checking and safemode-transition logic should be
part of the backbone. On the other hand, more elaborate FDC structures
