Next-Gen Plasma Thruster Rollout

Phase Four's Next-Generation Plasma Propulsion System

The space technology company, Phase Four, is scheduled to launch the subsequent generation of its Maxwell radio-frequency plasma propulsion system in the coming year. This advancement is designed to provide spacecraft with enhanced operational flexibility through improved performance characteristics.

Key Performance Metrics for Spacecraft Propulsion

When considering the movement of satellites within the vacuum of space, two primary factors are crucial: thrust and specific impulse (ISP). ISP quantifies a system's efficiency, measuring the thrust generated per unit of propellant consumed.

Trade-offs in Propulsion System Design

These performance characteristics present particular challenges for manufacturers of smaller spacecraft. High-thrust systems necessitate substantial fuel reserves, which can be a significant cost for satellites with limited size. Conversely, propulsion technologies prioritizing high ISP may not be suitable for missions involving rideshare launches, where independent orbital insertion is required.

Traditional electric thrusters often maximize specific impulse but compromise on thrust. While highly efficient, achieving orbital maneuvers can extend over several months.

Maxwell Thrusters: Bridging the Performance Gap

Phase Four’s Maxwell thrusters overcome this conventional trade-off, enabling operation in either a high-thrust or high-ISP mode, as explained by CTO Umair Siddiqui. This capability allows for rapid maneuvers when needed, or propellant conservation through high ISP operation.

Performance Improvements with Maxwell Block 2

The initial Maxwell product, the Block 1 thruster, introduced these innovative features. The subsequent iteration, Maxwell Block 2, delivers an approximate 85% enhancement in these key metrics. Siddiqui emphasized the significance of this improvement, stating that it translates to reduced propellant consumption or faster orbital maneuvering times.

Innovative Design and Manufacturing

Phase Four’s Maxwell thrusters incorporate several unique design elements. Traditional plasma thrusters, specifically Hall-effect thrusters, rely on difficult-to-manufacture cathode materials and tend to be bulky.

To address these limitations, Phase Four utilizes radio-frequency plasma sources instead of cathodes and anodes for thrust generation. This results in a more compact thruster that is easier to produce and can accommodate a wider range of gaseous propellants, moving beyond expensive options like xenon or krypton.

Streamlined Production and Modular Design

The company aims to maintain production cycles of under four months for the Block 2 thruster, a target initially achieved with the Block 1. This rapid turnaround is facilitated by the product’s modular design, drawing inspiration from automotive manufacturing practices.

“We can continue utilizing the existing production line to integrate future advancements, which is a fundamental requirement for the product,” Siddiqui noted. “It’s a plasma thruster designed with manufacturability as a core principle.”

Company Progress and Funding

Founded in 2015, Phase Four has already delivered ten Maxwell Block 1 systems to its customer base. This summer, the company secured $26 million in Series B funding, led by New Science Ventures LLC.