Phase Four will accelerate infrastructure expansion in space through the development of high performance plasma propulsion systems manufactured at scale, and the development of advanced propellants.

Maxwell is a complete plasma propulsion system, leveraging high efficiency miniaturized RF electronics and electrodeless design, to deliver plasma propulsion in a small package.

Maxwell Product Evolution

Maxwell Block 1


Maxwell Block 1 is a turn-key electric propulsion solution for next generation small satellites. It includes our proprietary RF thruster, power electronics, 1.26 kg xenon propellant tank, and flight software in a small package for volume-constrained small satellites.

Price: From $250,000

Maxwell Block 2

Q1 2022

Maxwell Block 2 takes the thruster, electronics, and fluid systems from Block 1 and arranges them in a panel-integrated fashion. This allows the system to mate to a variety of propellant tanks for different mission total impulse requirements while still using the same production line and production schedule. Block 2 is under development and is scheduled for first deliveries in Q2 2022.

Price: From $340,000

Maxwell Block 3

Second Half of 2022

Maxwell Block 3 incorporates updates to the RF thruster and the PPU. This will enable operating points at 2x Isp compared to Block 1 (800+ s) in the same form factor and power range as Block 2, doubling the total impulse capability of the system without sacrificing thrust, power, and volume. Block 3 is under development and is planned for deliveries in the second half of 2022.

SpecificationBlock 1Block 2 (preliminary)Block 3 (preliminary)
Operating Power300 - 500 W300 - 500 W300 - 500 W
ThrustUp to 7 mNUp to 7 mNUp to 10 mN
Specific ImpulseUp to 400 sUp to 450 sUp to 800+ s
Total ImpulseUp to 5,000 NsVariable, can size tank to meet impulse needs.Variable, can size tank to meet impulse needs.
Dry Mass5.9 kg5 kg (excludes tank)TBD
Bus Voltage22 - 34 V26 - 34 V26 - 34 V
Telemetry ProtocolRS-422RS-422RS-422
Dimensions19 cm W x 13.5 cm H x 19 cm D22 cm W x 12 cm H x 24 cm D (excludes tank)22 cm W x 12 cm H x 24 cm D (excludes tank)


Maxwell systems delivered


Maxwell systems in orbit

Example mission specifications using a qualified tank supplier:

The Table to the right shows example mission specifications using a qualified COPV tank supplier. Both larger and smaller tank sizes are available to customize Maxwell to meet your mission needs. The operating point shown is available as early as Block 2. Contact us today to find the right solution for your spacecraft and constellation.

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TANK DRY MASS1.5 kg (excluding harnessing)
MEOP3,000 psi
TOTAL IMPULSEUp to 43,000 N-s