The Segment Alignment Maintenance System (SAMS) software is designed to maintain the overall focus and figure of the large segmented primary mirror of the Hobby-Eberly Telescope. This software reads measurements made by sensors attached to the segments of the primary mirror and from these measurements computes optimal control values to send to actuators that move the mirror segments. The software also acts as a logger for the collected data, a server from which the hardware of the control computer can acquire control information and other computers can collect data, and a monitoring and diagnostic system. The software provides a graphical user interface through which human operators can exert control. The software supports four modes of operation:

  • Operate — The server acquires the sensory data and processes them into commands for the actuators.
  • Calibrate — Calibration tests are performed on the edge sensors and the relationships between actuator commands and sensor responses are quantified.
  • Standby — The server is initialized in standby mode, from which it can make the transition to any of the other three modes.
  • Diagnostic — This mode provides access to all sensory data in real time and is intended for use in diagnosis of sensor anomalies.

This program was written by Drew P. Hall, Richard T. Howard, William C. Ly, John M. Rakoczy, and John M. Weir of Marshall Space Flight Center. For further information, contact Jim Dowdy, Commercialization Project Lead, at This email address is being protected from spambots. You need JavaScript enabled to view it.. MFS-31835-1

NASA Tech Briefs Magazine

This article first appeared in the May, 2006 issue of NASA Tech Briefs Magazine.

Read more articles from the archives here.