Maxwell thrusters
Phase Four's new Maxwell Block 2 electric thruster (left) next to its original Block 1 thruster. Credit: Phase Four

WASHINGTON — Satellite electric propulsion company Phase Four has completed testing of a new thruster that it says offers significantly improved performance.

The El Segundo, California-based company said Dec. 1 that testing of the Block 2 version of its Maxwell radio-frequency thruster, announced earlier this year, showed a performance improvement of 85%, measured in terms of thrust and specific impulse, allowing the company to move into production of the new version.

The performance increase was the result of “three to four small to medium-sized tweaks,” said Umair Siddiqui, chief technology officer of Phase Four, in an interview. Those factors include the frequency the thruster operates at, propellant flow rates and other engineering constraints on the thruster.

The company’s original Block 1 thruster has flight experience on several spacecraft, including those operated by synthetic aperture radar imaging company Capella. The focus of the company for the last two years has been in developing that original thruster and building up a production line for them.

“Now the focus is returning back to iterating on the thruster design to optimize performance,” Siddiqui said. “Now you can have a cell of engineers who are focusing on the efficiency of the engine, the thrust of the engine, and so on, and when those new developments get released, they can installed into our manufacturing line.”

Beua Jarvis, chief executive of Phase Four, said the company now has a team dedicated to production of thrusters “so the engineers can go back to being engineers, which I suspect will give us higher performing systems much faster than we’ve able to do to date.”

The first Block 2 thrusters will be delivered to customers in the first half of 2022. “We have multiple smallsat constellation customers” for those thrusters, Jarvis said.

Phase Four is already planning for a Block 3 version of Maxwell that will include improvements to the electronics for higher efficiency, as well as changes to the fluid management system to allow the thrusters to be shipped fully fueled, rather than be fueled at the launch site.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...