To: Edgar Castro

From: Jon Hagen

Date: 3-3-99

Subject: Monthly report for Feb. '99

The second overspeed limiter (emergency brake trigger) is almost ready for installation on the carriage house. It needs only an electrical test and receipt of a steel pivot hinge pin that is being made in the Ithaca lab. Some preliminary design work is underway for an electrical overspeed damper - an electrical version of a hydraulic system proposed several months ago. Either system would provide entirely passive damping, limiting the maximum speed to the slew speed limit, even in the event of failure of the electrical drive system controllers and the brakes.

The effort to update the instruction manual and schematics for the 430 MHz transmitter is now about 80% complete.

Work is still underway to diagnose the foldback stopping of the tiedown drive systems.

Progress is being made on the tertiary drive systems. The circuitry for local control (independent of the local or remote computer) is nearly designed.