Case Study: Innovative generator units power the next generation of electric rocket propulsion.
August 14, 2020

Our RF PPU (radio-frequency power processing unit), built for Ad Astra, was tested for the first time at full-power at the rocket company’s facility in Webster, Texas on January 20th of this year.

Ad Astra Rocket Company (AARC) is a Houston, Texas-based company developing electric rocket technology for spacecraft propulsion. The company was founded in 2005 by Astronaut, Dr. Franklin Chang Diaz with the intent of commercializing his Variable Specific Impulse Magnetoplasma Rocket (VASIMR) technology.

A power-processing unit is fundamental to any electric rocket. It’s the part that takes the DC power from a solar array and converts it to something that can drive the plasma to produce thrust. 

The custom-built unit, designed by Aethera, successfully completed the magnetic field test, which involved operating the unit in hard vacuum and thermal steady state at its full power rating of 120 kW. As part of the test, for the first time, the PPU was subjected to the intense magnetic field of the VASIMR engine to verify that there are no negative effects on the PPU performance. 

With this test, Ad Astra successfully completed one of the three remaining major technology milestones in the NextSTEP Partnership Program contract with NASA for the maturation of the VASIMR engine. The Aethera RF PPU is now fully positioned at technology readiness level (TRL) 5; that is, all critical engine components have now been operated at full power in a relevant environment under vacuum.

“Watching the test was like a dream with all parameters maintaining very comfortable margins. What seemed like an easy test was a testimony to the quality of the teams that developed and tested this beautiful piece of equipment.” 

Jared Squire, Senior VP Research, Ad Astra Rocket Company

Aethera’s Chief Technical Officer, Tim Hardy, was the lead RF engineer on this project and gives much of the credit to the design teams involved.

“The environmental requirements for vacuum and magnetic field were key … for the RF PPU and having a successful result on the first test was a big achievement for the design teams,” said Hardy, “We’re looking forward to continuing positive outcomes as the Ad-Astra team prepares the VASIMR engine for its first flight.”

Due to the lightweight design, energy efficiency, and reliability of Aethera’s power-processing unit, Ad Astra was able to advance beyond its competitors in NASA trials.

Two milestones now remain in Ad Astra’s queue and are planned for completion this spring. These involve long duration 100 kW firings of the VX-200SS VASIMR test article; one for 5-6 hours to demonstrate thermal control of the engine and a second, for 100 hours, to estimate component life. Upon completion of these milestones, Ad Astra will move to the next technology maturation phase: the development of a TRL-6 VASIMR engine for a flight test.

This project was an exciting challenge for our company and we’re thrilled with the result. We look forward to future challenges and continuing to help our clients achieve success through the use of RF power.

For more technical information about the test, read the full press release from Ad Astra Rocket Company.

To learn more about Aethera’s involvement in this project, download our case study.