304
9 OBDH Technology of Lunar Lander
high integration and miniaturization. The technical features, design methods and
verification of OBDH are introduced in this chapter.
9.2 Development Status
Before 1970s, there was no concept of data management system on Chinese
spacecraft. Telemetry subsystem, telecommand subsystem and tracking subsystem
were relatively independent, which were called TT&C (Telemetry Tracking and
Command) system. Since 1980s, along with the growing complexity of spacecraft,
many autonomous task requirements had been put forward, such as program control,
time-delay command, payload operation management, energy management, thermal
control management, system level security management, system level reconfiguration, onboard time system, and data exchange and sharing among subsystems. At
first, the traditional TT&C system of some remote sensing satellite was designed to
be an on-board data management system (OBDH/C&DH). A hierarchical distributed
computer system and modular structure was applied. Its function was extended from
relatively simple TT&C to autonomous management of the whole spacecraft. The
on-board data could be comprehensively utilized. At the same time, program control
and autonomous control function of spacecraft could be implemented, which enabled
autonomous capability of flight and the maintainability on orbit so as to greatly
improve capabilities of spacecraft TT&C and survivability of spacecraft.
According to the development of space applications, the types and number of
spacecraft were greatly increased, while the tasks and functions were becoming
more and more complex. The success of space missions depended on whether the
spacecraft could reliably implement task management, data processing and information exchange [3]. While more attention was paid to the information flow of spacecraft, the OBDH subsystem played more important role and extends its scope. The
design of OBDH subsystem had evolved into a system design which was intersecting
with many specialized fields including the design of top lever information flow, bus
network and communication protocol, thermal control, autonomous management of
power supply, telemetry format, and etc. The proposal and design of OBDH played
an irreplaceable role in spacecraft system design and subsequent development.
Recently, following trends were shown in development of electronic systems of
spacecraft.
(1) The function of autonomous management and intellectuality of spacecraft
on orbit was improved. The functions of traditional telemetry and telecommand, data management, attitude and orbit control, thermal control, power
management, and payload management were integrated, as well as autonomous
management functions such as information management, resource management, operation management and crisis management (fault detection, reconfiguration, task downgrade and safe mode operation). Such on-board functions
could reduce the burden of long-term on-orbit management, and effectively
improve the autonomous diagnosis and autonomous survivability of spacecraft.
9 OBDH Technology of Lunar Lander
high integration and miniaturization. The technical features, design methods and
verification of OBDH are introduced in this chapter.
9.2 Development Status
Before 1970s, there was no concept of data management system on Chinese
spacecraft. Telemetry subsystem, telecommand subsystem and tracking subsystem
were relatively independent, which were called TT&C (Telemetry Tracking and
Command) system. Since 1980s, along with the growing complexity of spacecraft,
many autonomous task requirements had been put forward, such as program control,
time-delay command, payload operation management, energy management, thermal
control management, system level security management, system level reconfiguration, onboard time system, and data exchange and sharing among subsystems. At
first, the traditional TT&C system of some remote sensing satellite was designed to
be an on-board data management system (OBDH/C&DH). A hierarchical distributed
computer system and modular structure was applied. Its function was extended from
relatively simple TT&C to autonomous management of the whole spacecraft. The
on-board data could be comprehensively utilized. At the same time, program control
and autonomous control function of spacecraft could be implemented, which enabled
autonomous capability of flight and the maintainability on orbit so as to greatly
improve capabilities of spacecraft TT&C and survivability of spacecraft.
According to the development of space applications, the types and number of
spacecraft were greatly increased, while the tasks and functions were becoming
more and more complex. The success of space missions depended on whether the
spacecraft could reliably implement task management, data processing and information exchange [3]. While more attention was paid to the information flow of spacecraft, the OBDH subsystem played more important role and extends its scope. The
design of OBDH subsystem had evolved into a system design which was intersecting
with many specialized fields including the design of top lever information flow, bus
network and communication protocol, thermal control, autonomous management of
power supply, telemetry format, and etc. The proposal and design of OBDH played
an irreplaceable role in spacecraft system design and subsequent development.
Recently, following trends were shown in development of electronic systems of
spacecraft.
(1) The function of autonomous management and intellectuality of spacecraft
on orbit was improved. The functions of traditional telemetry and telecommand, data management, attitude and orbit control, thermal control, power
management, and payload management were integrated, as well as autonomous
management functions such as information management, resource management, operation management and crisis management (fault detection, reconfiguration, task downgrade and safe mode operation). Such on-board functions
could reduce the burden of long-term on-orbit management, and effectively
improve the autonomous diagnosis and autonomous survivability of spacecraft.