Space-Qualified Traveling-Wave Tube

TWT was developed for use as a high-power microwave amplifier for high-rate transmission of data.

The L-3 Communications Electron Technologies, Inc. Model 999HA traveling-wave tube (TWT), was developed for use as a high-power microwave amplifier for high-rate transmission of data and video signals from deep space to Earth (see figure). The 999HA is a successor to the 999H — a non-space-qualified TWT described in “High-Power, High-Efficiency Ka-Band Traveling-Wave Tube” (lew-17900-1), NASA Tech Briefs, Vol. 31, No. 2 (February 2007), page 32. Operating in the 31.8-to-32.3 GHz frequency band, the 999HA has been shown to generate 252 W of continuous-wave output power at 62 percent overall power efficiency — a 75-percent increase in output power over the 999H.

The mass of the 999HA is 35 percent less than that of the 999H. Moreover, taking account of the elimination of a Faraday cage that is necessary for operation of the 999H but is obviated by a redesign of high-voltage feedthroughs for the 999HA, the overall reduction in mass becomes 57 percent with an 82 percent reduction in volume. Through a series of rigorous tests, the 999HA has been qualified for operation aboard spacecraft with a lifetime exceeding seven years. Offspring of the 999HA will fly on the Kepler and Lunar Reconnaissance Orbiter missions.

This work was done by Jeffrey D. Wilson, Richard Krawczyk, Rainee N. Simons, and Wallace D. Williams of Glenn Research Center and Neal R. Robbins, Daniel R. Dibb, William L. Menninger, Xiaoling Zhai, and Robert T. Benton of L-3 Communications Electron Technologies, Inc. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Electronics/Computers category.

Inquiries concerning rights for the commercial use of this invention should be addressed to NASA Glenn Research Center, Innovative Partnerships Office, Attn: Steve Fedor, Mail Stop 4–8, 21000 Brookpark Road, Cleveland, Ohio 44135. Refer to LEW-18220-1.