Interim User's Requirements Collection (IURC) is a software system that generates an interactive graphical user interface that enables users of the International Space Station (ISS) to specify their payload-planning and -scheduling requirements via the World Wide Web (WWW). IURC includes (1) a Java applet that is dynamically distributed via the WWW and (2) four application programs that run on a dedicated host computer with a web server at Marshall Space Flight Center (MSFC).

The need for a system like IURC to collect ISS payload planning and scheduling requirements arises from several causes. The requirements are complex, lengthy, and diverse. The scarcity of Space Station resources causes significant competition for resources among experiments. In order to be able to perform its scheduling task, the Payload Operations Integration Center at MSFC needs a concise and comprehensive description of payload requirements (to ensure a valid schedule) and a good description of the payload flexibilities (to provide for effective utilization of available resources). In addition, the continuous operation of the ISS, the wide geographic dispersion of ISS users, and budgetary pressure to employ fewer operational personnel have made it necessary to seek an inexpensive solution in the form of software.

IURC incorporates three distinct innovations that synergistically ensure effectiveness in the collection of planning and scheduling requirements, with the needed fidelity and convenience, and at a cost less than the costs of other methods. These innovations are the following:

  • The major innovation is a provision for graphical specification of requirements. IURC does more than merely use graphics to depict or interpret data entered via tables or forms; the graphical user interface is the data-entry mechanism.
  • IURC provides "just-in-time" configuration control that is not visible to users. Configuration control begins when a user says that a set of data is ready to go; at this point, IURC makes a copy of the set of data. Users who enter data never see any effect of configuration control. Their data are not "locked," so that users never need to request that the data be "unlocked." Users are free to edit their data at will. However, the copies of data that users have designated as being ready to go and that are being used to produce ISS time lines are under full configuration control.
  • The WWW implementation enables a user to interact with the system via a personal computer from any location. All data are kept on the web server at MSFC; except for entering data as described above, users never move, send, or track their data. In addition, by utilizing the combination of (1) a universally installed web browser and (2) the dynamically downloaded JAVA applet, IURC eliminates the need for users to install any software, yet is globally available to users.

This work was done by John Jaap and Elizabeth Davis of Marshall Space Flight Center. For further information, please contact the MSFC Software Release Authority at (256) 544-7175. MFS-31416