Spacecraft computer resource margin management
(Previously cited in issue 01, p. 122, Accession no. A82-10089)
Larman, B. T.↗
Engineering topics
Larman, B. T.
Publications and source records attributed to Larman, B. T..
Spacecraft computer resource margin management
The conduction of the Project Galileo Orbiter, with 18 microcomputers and the equivalent of 360K 8-bit bytes of memory contained within two major engineering subsystems and eight science instruments, requires that the key onboard computer system resources be managed in a very rigorous manner. Attention is given to the rationale behind the project policy, the development stage, the preliminary design stage, the design/implementation stage, and the optimization or 'scrubbing' stage. The implementation of the policy is discussed, taking into account the development of the Attitude and Articulation Control Subsystem (AACS) and the Command and Data Subsystem (CDS), the reporting of margin status, and the response to allocation oversubscription.
Larman, B. T.↗
Viking adaptive mission sequence and control operations
Viking mission operations were required to provide an adaptive sequencing capability in which future observations could be influenced by the latest information about Mars as it was obtained and analyzed. The mission operations strategy that was developed met this requirement and provided the capability to respond smoothly and efficiently to spacecraft subsystem anomalies with minimum impact on the science data gathering process. A description of the major elements of this adaptive man-in-the-loop control system is provided. Specific cases showing how it was utilized to enhance scientific return and to respond to spacecraft anomalies are also provided.
Larman, B. T.↗
The impact of robots on planetary mission operations
Unmanned roving vehicles sent to explore remote planetary surfaces must carry out some of their tasks without step-by-step human control. To realize the benefits that accrue from such semiautonomous machines, current planning (and carrying out) of mission profiles will be subject to some changes. Specifically, it is shown that mission profiles will have to be based on tasks or functions rather than sequences of timed events, while scientists will have to center their attention on instrument control. Present ideas concerning spacecraft safety, testing (and simulation) of vehicle performance, telemetry design, and ground station equipment must be reexamined.
Hooke, A. A.↗
Mariner 9 data storage subsystem flight performance summary
The performance is summarized of the Mariner 9 Data Storage Subsystem (DSS) throughout the primary and extended missions. Information presented is limited to reporting of anomalies which occurred during the playback sequences. Tables and figures describe the anomalies (dropouts, missing and added bits, in the imaging data) as a function of time (accumulated tape passes). The data results indicate that the performance of the DSS was satisfactory and within specification throughout the mission. The data presented is taken from the Spacecraft Team Incident/Surprise Anomaly Log recorded during the mission. Pertinent statistics concerning the tape transport performance are given. Also presented is a brief description of DSS operation, particularly that related to the recorded anomalies. This covers the video data encoding and how it is interpreted/decoded by ground data processing and the functional operation of the DSS in abnormal conditions such as loss of lock to the playback signal.
Thomas, N. E.↗