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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.

Product Suite

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.

From $250,000


Available Now

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 available for order now.

From $340,000


H2 2023

Maxwell Block 3 incorporates updates to the RF thruster. These updates enable a nominal operating point of 14 mN thrust and 1,456 s Isp. This represents a 2x specific impulse improvement over the Block 2 engine at this operating point. Block 3 will be available for order in the second half of 2023.


H2 2023

Max-V leverages the Maxwell Block 2 engine's innovative architecture and builds on the radio-frequency thruster's propellant agnostic capabilities. Max-V replaces traditional high cost noble gas propellant with domestically sourced iodine-based propellant. Availability is expected in the second half of 2023.

Operating Power 300 - 500 W 300 - 500 W 300 - 500 W 200 W - 1.5 kW
Thrust Up to 7 mN Up to 13 mN Nominal operating point of 14 mN with 1,456 s Isp using xenon. 11 mN with 1,160 s Isp using krypton. Note higher thrust modes are possible with lower Isp. 50+ mN
Specific Impulse Up to 400 s Up to 700 s 1,456 s with xenon. 1,160 s with krypton. 1,200+ s
Total Impulse Up to 5,000 Ns Variable, can size tank to meet impulse needs. Variable, can size tank to meet impulse needs. 100+ kNs
Dry Mass 5.9 kg 5 kg (excludes tank) 7 kg (excludes tank) TBD
Bus Voltage 22 - 34 V 26 - 34 V 26 - 34 V 26 - 34 V
Telemetry Protocol RS-422 RS-422 RS-422 RS-422
Dimensions 19 cm W x 13.5 cm H x 19 cm D 22 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) (Preliminary) 22 cm W x 12 cm H x 24 cm D (excludes tank)


Maxwell systems delivered



Maxwell systems in orbit

Product Gallery

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.

TANK DRY MASS 1.5 kg (excluding harnessing)
MEOP 3,000 psi
TOTAL IMPULSE Up to 64,000 N-s

*Intellectual Property Notice: The systems and processes discussed and disclosed herein are covered by one or all of the following patents: U.S. Pat. No. 11,067,065 and U.S. Pat. No. 11,231,023. Other systems and processes are patent pending in the U.S. and E.P.O.