Designing a Radio Frequency Processing Unit with 98% energy efficiency for the VASIMR thruster

We teamed with Aethera Technologies to design the Ion Cyclotron Heater Radio Frequency Processing Unit, one of the key components of the Variable Specific Impulse Magnetoplasma Rocket System (VASIMR), with 98% energy efficiency.

Aethera Technologies is an electronics engineering Research & Development firm that’s recognized for using Radio Frequency (RF) power to innovate across a wide range of applications.

They were initially tasked by Ad Astra Rocket Company to design a new type of power supply for their electric rocket, the VASIMR (Variable Specific Impulse Magnetoplasma Rocket) system. The VASIMR system, under development at Ad Astra, is a radio frequency (RF) powered, fully magnetized plasma thruster designed for in-space propulsion.

Aethera, at the time, needed an extra hand to dive into the mechanical engineering and design aspects of the project, and so they sought out the help of Enginuity’s Mechanical Engineering and Design team.

The RF power processing unit is one of the key components of this type of electric rocket, as the device is responsible for supplying high frequency power to heat the plasma exhaust. It was important to come up with a design that was both electrically efficient, while still meeting the design specifications such as form factor, mass, and volume.

Aethera Technologies

Aethera Technologies sought out the help of Enginuity’s Mechanical Engineering and Design team in order to assist with the design one of the key components of Ad Astra Rocket Company‘s electric rocket system (VASIMR), the Ion Cyclotron Heater RF Processing Unit.

Together, Enginuity and Aethera were able to come up with a highly optimized design for this Power Processing Unit (PPU) that met the tight restrictions required for space propulsion – at 98% energy efficiency.

The Enginuity Solution

Enginuity’s team of mechanical engineers and technologists were able to come up with a design configuration that was both thermally and mechanically optimized, that also met the tight restrictions required for space. The result was a compact assembly of amplifiers, transformers, control boards, and conductive cooling held in one magnetically shielded volume.

According to Enginuity’s Mechanical Lead Lou Manuge, one of the challenges that they faced along the way was figuring out a thermal design for the power supply; thermal loads in the device generated from small losses in power-electronics components could lead to system failure without a robust cooling system, capable of channeling heat in the vacuum of space.

Through several design iterations, the team was able to balance mechanical layout, thermal design, electrical design and converged on an acceptable architecture that would satisfy all project requirements.

In the end, the power processing unit had an energy efficiency of 98% and had a mass on the order of 40% of the previous generation system.

“We were able to successfully design a configuration that worked both mechanically and thermally and fit into the magnetic shielding, meeting the mass and volume and specifications. We (Aethera and Enginuity) were able to build the device and test it, all with great success. The performance was great, the mass and volume were all on budget, and it turned out really well,” Lou Manuge said.

In photo: Franklin Chang Diaz

Our Impact

“It’s one thing to have a very efficient rocket, but you still need to put propellant through it. If you can get more efficiency, and more thrust out of the same fuel, then it’s worth it, because fuel is so expensive to get into space.” Lou explains.

An optimized power processing system has a huge effect on the overall performance of the rocket, as the energy efficiency of the PPU (Power Processing Unit) directly effects the rocket efficiency. Having a system that can maximize power efficiency leads to better performance and cost-effectiveness for the entire spacecraft.

We were able to contribute to the overall efficacy of the rocket system in many ways and in the end provided an impressively efficient configuration – highly optimized for mass, form-factor, and capable of operating at thermal steady state for long-term missions, all within the rocket’s own intense magnetic field.

What’s Next?

Since then, Aethera has worked with Enginuity on many projects. Enginuity is looking forward to the continued success of Aethera Technologies and for the possibilities of continuing to work together in the future.

We are also looking forward to the completion of the VASIMR System, as Ad Astra’s current projection is that a nuclear electric version of VASIMR could reduce the flight time from Mars from 9 months to <80 days.

To find out more about Aethera Technologies, you may visit their website here:

For more information about Ad Astra Rocket Company, visit:

You can also read more about the VASIMR System in full here.

*VASIMR is a registered trademark of AARC.