Complex pressure systems are utilized during testing in the propulsion branch as well as during the propellant loading stage of a mission. Keeping track of the state of such a system becomes more difficult as the complexity of such a system increases, and when extensive procedures are being followed. A book-keeping system is needed for visualizing these complex systems.

Visualization of the Global Precipitation Measurement (GPM) propellant loading configuration.
This software was created to keep track of and easily visualize the different states of complex pressure systems and their configurations. The user can enable front-panel components, open/close valves and regulators, and connect various components together all on a graphical user interface (see figure). On screen, the schematic will programmatically update its appearance to represent this user input.

The logic itself is very modular and dependent on sub-methods that encapsulate common components. For instance, there are sub-methods created to represent the behavior of the valves, regulators, gauges, etc. Combining these methods with a blank template that is also provided allows for easily repeatable code. Additionally, the program is developed in LabVIEW, which is a graphical programming language. This allows a user to build software based on this system by following the user guide, even with little to no background dealing with programming.

The most novel feature of this software is its approach to handling the interaction of different media (gas, liquid, vacuum, ambient, vent) represented in the program. Instead of performing complex calculations, each different medium is represented by a numeric value corresponding to a color seen on screen (gas = green, vacuum = red, liquid = blue, etc.). By using a hierarchy to govern the interaction between two different media, the only calculations that need to take place are simple comparisons. Additionally, the use of sub-methods and a predetermined template are the key to making the software easily modifiable and reconfigurable for other uses.

This software dramatically reduces the time it takes to change the status of a component, while putting it in a more presentable and easily followed form. Additionally, it adds a layer of functionality by displaying and autonomously updating the medium present in each tubing section based on the user’s input (component position change, equipment connection, etc.).

This work was done by Bryan Friia and Graham Webster of Goddard Space Flight Center. GSC-16705-1

NASA Tech Briefs Magazine

This article first appeared in the February, 2015 issue of NASA Tech Briefs Magazine.

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