Miller, Robert — Page 2 | Engineering Papers

NASA NTRS1989

Operational efficiency increase in a copper vapor laser due to the replacement of vacuum jacket brewster windows with flat windows

The vacuum integrity of the discharge tube of a copper vapor laser (CVL) is normally protected by Brewster angled windows. In an attempt to increase the operating efficiency of the CVL, flat windows were used to replace the Brewster windows. Experimental data confirm that the overall efficiency of the CVL does increase when such windows are used. The experimental results are discussed in terms of a computer model found in the literature. The cause of the efficiency increase appears due to a double optical cavity set up by the flat windows. However, the variation of the efficiency due to changes in the pulse repetition frequency (PRF) and buffer gas pressure are less well understood.

Estep, Lee↗

NASA NTRS1987

Centaur G Prime modal test

The Centaur G Prime modal test resulted in sets of modes (frequencies, mode shapes and damping) with an accuracy similiar to or better than that normally obtained from the modal testing of linear structures with no backlash and small damping. In other words, performing the test at high level greatly minimized the backlash effect and provided a valid, simple linearization of the trunnion friction problem for the Centaur in the Shuttle Cargo Bay. All the most important modes (target modes) were measured and provided the data base for updating the finite element model for the pre-flight verification loads analysis.

Trubert, Marc↗