NTRS - NASA Technical Reports Server

As of October 27, 2023, NASA STI Services will no longer have an embargo for accepted manuscripts. For more information visit NTRS News.

Back to Results
Using Common Graphics Paradigms Implemented in a Java Applet to Represent Complex Scheduling RequirementsThe experiments planned for the International Space Station promise to be complex, lengthy and diverse. The scarcity of the space station resources will cause significant competition for resources between experiments. The scheduling job facing the Space Station mission planning software requires a concise and comprehensive description of the experiments' requirements (to ensure a valid schedule) and a good description of the experiments' flexibility (to effectively utilize available resources). In addition, the continuous operation of the station, the wide geographic dispersion of station users, and the budgetary pressure to reduce operations manpower make a low-cost solution mandatory. A graphical representation of the scheduling requirements for station payloads implemented via an Internet-based application promises to be an elegant solution that addresses all of these issues. The graphical representation of experiment requirements permits a station user to describe his experiment by defining "activities" and "sequences of activities". Activities define the resource requirements (with alternatives) and other quantitative constraints of tasks to be performed. Activities definitions use an "outline" graphics paradigm. Sequences define the time relationships between activities. Sequences may also define time relationships with activities of other payloads or space station systems. Sequences of activities are described by a "network" graphics paradigm. The bulk of this paper will describe the graphical approach to representing requirements and provide examples that show the ease and clarity with which complex requirements can be represented. A Java applet, to run in a web browser, is being developed to support the graphical representation of payload scheduling requirements. Implementing the entry and editing of requirements via the web solves the problems introduced by the geographic dispersion of users. Reducing manpower is accomplished by developing a concise representation which eliminates the misunderstanding possible with verbose representations and which captures the complete requirements and flexibility of the experiments.
Document ID
Document Type
Reprint (Version printed in journal)
Jaap, John
(NASA Marshall Space Flight Center Huntsville, AL United States)
Meyer, Patrick
(NASA Marshall Space Flight Center Huntsville, AL United States)
Davis, Elizabeth
(NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1997
Subject Category
Computer Programming And Software
Meeting Information
Meeting: Planning and Scheduling for Space
Location: Pasadena, CA
Country: United States
Start Date: October 28, 1997
Distribution Limits

Available Downloads

There are no available downloads for this record.
No Preview Available