Engineering topics
Publications and source records attributed to Turner, P. R..
The continuing development of new spacecraft technologies promises to enable the Solar Probe to be the first mission to travel in the atmosphere or corona of the Sun. The most significant technology challenge is the thermal shield that would protect the spacecraft from the flux of 3000 Suns (400 W/cm**2) at the perihelion radius of 4 solar radii while allowing the spacecraft subsystems to operate at near room temperature.
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Smaller and lower cost options of NASA's Solar Probe mission have recently been studied. The difference between these options and the results of earlier studies is dramatic. The motivation for low cost has encouraged the JPL design team to accomodate a smaller scientific payload using innovative multi-functional subsystems.
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In the decades since the advent of in situ plasma measurements on board spacecraft, the instrumentation has grown bigger, heavier, and more complex as our understanding of space plasmas improves and our appetite for more information increases...There has thus been a recent interest in the miniaturization of both spacecraft and the instrument payload... This paper describes the results and status of an ongoing design study to understand the problems and trade space of fully integrating an instrument into a micro-spacecraft.
This paper discusses the design concept of the Mars Rover/Sample Return (MRSR) mission. Special consideration is given to the issues of the power source, the scale and performance of the mobility subsystem, the requirements of the sampling subsystem, and the degree of automation, as well as to the features and the orbit design of a Mars orbiting vehicle (MOV) supporting the landed operations. The details of the integrated aeroshell configuration, that includes the rover, the lander, and the MOV during the Mars orbit insertion phase are described, and the diagrams of the MRSR mission and its elements are presented.
A methodology for autonomous spacecraft design blends autonomy requirements with traditional mission requirements and assesses the impact of autonomy upon the total system resources available to support fault-tolerance and automation. A baseline functional design can be examined for autonomy implementation impacts, and the costs, risk, and benefits of various options can be assessed. The result of the process is a baseline design that includes autonomous control functions.
Some major steps are summarized in the evolution of autonomous design features for planetary exploration spacecraft. The control and data architectures for the Viking, Voyager, and Galileo spacecraft are considered. Telemetry and command capabilities are fundamental features of spacecraft design that have been successfully used for autonomous control. Also discussed is the Autonomous Redundancy and Maintenance Management Subsystem (ARMMS) concept. The software approach to autonomous control provides for modifications to the control process or the addition of new operating features during flight operations.
The Space Station crew will be a critical resource for economical operation of science and commercial payloads. Core station housekeeping and maintenance functions should be provided in a manner that requires a minimum of crew interaction. This paper outlines a prospective functional architecture for allocation of autonomous and automated control of these functions and discusses implementation issues arising from safety of manned operations, integration test requirements, and evolution of future station capabilities.