Steve Jurvetson Apollo Command Module USB TWT Amplifier

The original USB — Unified S-Band, a common communication channel used during the Apollo missions. With just 20 Watts, they could communicate with Houston from the moon. And a single antenna combined voice, television, command, tracking and ranging. From the Future Ventures’ Space Collection.

This fully redundant Command Module S-Band Amplifier output was routed to the High Gain and Omni-Directional antenna's on the CSM. It is stamped Serial No. 0006

Even today, this type of specialty vacuum tube is among the most efficient and compact types of RF amplifier. As a result, many high-tech satellites still feature these devices.

This photo and detailed analysis come from the Ken Shirriff blog, which became popular with places like Hackaday:

“How did the Apollo astronauts communicate 240,000 miles back to Earth? With an amplifier that was just 20 watts, built from special traveling-wave tubes. I look inside this amplifier in my latest blog post”

Flickr file: www.flickr.com/photos/jurvetson/51319874206/in/feed-22706-1626635793-1-72157719556711443


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