An Atlantic company that specializes in manufacturing broadcast radio frequency (RF) amplifier technologies is applying its sound wave expertise to develop generators for a plasma propulsion rocket engine.

This may seem like a galactic leap for Nautel, a 40-year-old company with an international reputation for its high power solid-state radio broadcast transmitters, but it’s not. Nautel is applying robust R&D capabilities to expand its technology to diversify into non-communication applications, and this led to a partnership with Webster, Tex.-based Ad Astra Rocket Co. to build RF generators that power a Variable Specific Impulse Magnetoplasma Rocket (VASIMR VX-200) concept. This pre-warp speed propulsion, invented by Dr. Franklin Chang Diaz, founder of Ad Astra, would cut a lot of time off a typical space jaunt.

The technology, in development since 1979, would conceivably shorten a trip to Mars from up to two years (using existing rocket engine technology that costs millions of dollars) to about 40 days.

Electric rocket engine technologies supply about 10 kilowatts of power and currently available generators are large, primitive and impractical systems for space applications.

Ad Astra needed a small, light power generator capable of 200 kilowatts to power its plasma technology.

“They needed a device that simply didn’t exist,” says Tim Hardy, Nautel’s head of engineering. “First they needed the fundamental technology to power the engine and then they needed to take that technology and put it in a space environment.”

Nautel develops radio transmitters that drive big antennas by amplifying small radio signals to a much higher power, so it applied the same expertise to develop two generators—one that is 50 kilowatts and another that’s 180 kilowatts.

“The technology is very much the same,” says Hardy. “In the radio business we would put information on the signal. But in the generator application it’s just a continuous signal with no information.”

Traditional generators are typically installed in 1.8- by 1.5-metre racks and, depending on the power demand, there could be several of them. Nautel’s power units are the size of a golf bag.

The technology uses radio waves from the generator to heat argon gas.

“If you put enough energy into it [gas], the electrons separate away from the nuclei of the atoms and start to float around,” says Hardy. “As soon as that happens the gas becomes plasma.”

The plasma, which is a forced solid-state matter as hot as the sun’s surface, is then constrained and propelled by an intense magnetic field that forms a pipe, preventing the plasma from touching any physical matter as it flows down and expands outward.

NASA’s International Space Station—where the technology will be tested sometime next year—requires an annual reboost to keep it in orbit. It was deliberately positioned in a low orbit for easier access and to reduce costs, but it deteriorates by about one metre a day.

The annual cost of boosting it back into position is about $100 million. Plasma technology could reduce the cost to less than $10 million.

The project’s first phase demonstrated the technology is feasible and meets the power, size and weight specifications required by Ad Astra. The next step is to harden the generators to withstand the space environment.

Rare engineering capability
The company spends more than 10% of its annual revenue (about $30 million) on R&D and it has almost 40 engineers and technicians at its 70,000-square-foot integrated production facility, which is capable of rapid prototyping.

“Nautel holds a rare engineering capability that combines the specialized knowledge of efficient, compact high power RF amplifier design with modern digital control and signal processing,” says John Whyte, Nautel’s head of marketing and sales. “As a company we continuously review opportunities to apply this expertise in new application areas.”

Plasma propulsion is just one of Nautel’s new projects. It’s also developing industrial RF energy for drying and heating applications and exploring sonar system design.

“There are a lot of industrial processes that require heating and often there are different techniques to do that,” says Hardy. “The most basic system would be to use hot air, which is just heated by resistors or by burning something, or there’s microwave systems used in some applications.”

But he says microwave systems have limitations because they omit short wave lengths that aren’t as good at heating large structures uniformly.

Nautel is developing an application for drying wood.

“Imagine 10 cubic metres of wood… RF will dry it evenly and uniformly throughout,” explains Hardy. “This can speed up the process and produce a higher quality product.”

Involvement with the plasma rocket engine has put Nautel in a global spotlight, which is highlighting the company’s innovation capabilities.

Whyte calls the plasma project it’s Honda Racing program, and Hardy concurs. “Because we’re a company that’s trying to innovate and diversify into new markets, attention like this has people asking us what else we can do.”

To quote Captain Picard on the Starship Enterprise, Nautel is demonstrating it can “make it so.”

Noelle Stapinsky is the features editor of Canadian PLANT and Canadian Manufacturing.com. E-mail noelle.stapinsky@rci.rogers.com.

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