The Quest for the Ultimate Vacuum Tube

The cold-cathode traveling-wave tube, an ultracompact, ultraefficient source of RF waves, may finally be within reach

13 min read
The Quest for the Ultimate Vacuum Tube
Tubes in Space: The cold-cathode traveling-wave tube would make it possible to equip even very small communication satellites with powerful RF transmitters.
Photo: Sue Tallon

In July 1962, the Telstar 1 satellite took an enormous leap toward the globally connected world we now take for granted. It relayed from space, for the first time ever, live television images and telephone calls between continents: specifically, a ground station in Andover, Maine, and other stations in England and France. It accomplished this feat thanks to a microwave repeater that had at its heart a slight but powerful vacuum device known as a traveling-wave tube. The 30-centimeter-long, glass-walled electron tube was at the time the only device capable of boosting a broadband television signal with enough power to cross an ocean. Solid-state devices just weren’t up to the task.

More than a half century later, traveling-wave-tube amplifiers still dominate satellite communication. That’s right—your ultrahigh-definition satellite TV and satellite radio come to you courtesy of vacuum tubes in space.

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Engineers Are Working on a Solar Microgrid to Outlast Lunar Nights

Future lunar bases will need power for mining and astronaut survival

4 min read
A rendering of a lunar base. In the foreground are rows of solar panels and behind them are two astronauts standing in front of a glass dome with plants inside.
P. Carril/ESA

The next time humans land on the moon, they intend to stay awhile. For the Artemis program, NASA and its collaborators want to build a sustained presence on the moon, which includes setting up a base where astronauts can live and work.

One of the crucial elements for a functioning lunar base is a power supply. Sandia National Laboratories, a research and development lab that specializes in building microgrids for military bases, is teaming up with NASA to design one that will work on the moon.

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Trilobite-Inspired Camera Boasts Huge Depth of Field

New camera relies on “metalenses” that could be fabricated using a standard CMOS foundry

3 min read
Black and white image showing different white box shapes in rows

Scanning electron microscope image of the titanium oxide nanopillars that make up the metalens. The scale is 500 nanometers (nm).


Inspired by the eyes of extinct trilobites, researchers have created a miniature camera with a record-setting depth of field—the distance over which a camera can produce sharp images in a single photo. Their new study reveals that with the aid of artificial intelligence, their device can simultaneously image objects as near as 3 centimeters and as far away as 1.7 kilometers.

Five hundred million years ago, the oceans teemed with horseshoe-crab-like trilobites. Among the most successful of all early animals, these armored invertebrates lived on Earth for roughly 270 million years before going extinct.

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Distinguishing weak signals from noise is a challenging task in data acquisition. In this webinar, we will explain challenges and explore solutions. Register now!
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