Microwave Electrothermal Thruster Testing Continuing in Space

A new Microwave Electrothermal Thruster (MET) spacecraft engine design is undergoing a successful in-space testing campaign. Developed by Momentus, the microwave electrothermal thruster has completed more than a dozen test firings ranging from 30 seconds up to five minutes – the expected range for Momentus standard missions.

“We're already achieving burn times that are consistent with the operational times required for our missions and we anticipate significant opportunities for this technology in commercial and national security applications."

Momentus Chief Technology Officer Rob Schwarz.

The MET is the Vigoride Orbital Service Vehicle’s (OSV) (pictured, below) primary propulsion method that relies on solar power and uses distilled water as a propellant. It produces thrust by expelling extremely hot gases through a rocket nozzle. Unlike a conventional chemical rocket engine, which heats propellant through a chemical reaction, the microwave electrothermal thruster uses a solar powered, microwave energy source to generate a hot plasma at its core that heats the propellant to generate thrust. The use of non-toxic water propellant ultimately enables simpler, safer, and more cost-efficient operations both on Earth and in space.

“We have been doing multiple burns that raise the orbit of the spacecraft. Without propulsion, the spacecraft’s altitude decreases by about 50 meters per day. Now that we have been performing these burns, the spacecraft’s altitude has increased by nearly a kilometer and is growing,” said Momentus Chief Executive Officer John Rood. “We have been increasing the frequency of these burns and we are raising the orbit to a target value of 538 km circular altitude. We will use this orbit to release the Zeus satellite for our Qosmosys customer – marking the first time Momentus will achieve a custom orbital delivery service.”

Microwave Electrothermal Thruster has Reached 5 Minute Burn Goal

Momentus has incrementally been increasing the duration of each MET firing and has reached its goal of 5-minute firings. The electrical power system, including batteries and solar arrays have been supporting the high power (1000+ Watts) operation of the MET. The spacecraft's heat management system has operated effectively, keeping all critical component temperatures well below their maximum thresholds.

"The MET technology, which we are pioneers in commercializing, has key safety, efficiency, and sustainability advantages with the performance to make extraordinary missions happen for our customers,” said Momentus Chief Technology Officer Rob Schwarz. “We're already achieving burn times that are consistent with the operational times required for our missions and we anticipate significant opportunities for this technology in commercial and national security applications. From the near-term demand of low-Earth orbit transportation missions to support for military applications, to future satellite servicing in GEO, to one day refueling with water sourced from the Moon and beyond – the Momentus MET is designed to be a mainstay of new ways of operating in space."

The Vigoride OSV’s Attitude Control and Reaction Control Systems also use water as a propellant and were recently tested and fully commissioned. With its water-based propulsion systems, Momentus aims to offer cost-effective, efficient, safe, and environmentally friendly propulsion to meet the demands for in-space transportation and infrastructure services.

(Source: Momentus news release. Images from file)