RKLBRocket Lab+Neutron.DevLUNRIntuitive+IM-2.LandingASTSAST Space+BlueBird.DeployPLPlanet Labs+Pelican.LaunchBKSYBlackSky+Gen-3.LiveSPIRSpire+100.SatsRDWRedwire+ISM.ModuleIRDMIridium+IoT.ExpandVSATViasat+ViaSat-3.LiveSPACEXSpaceX+Starship.V3FUND.YTD2025-26$12B+.Raised
Companies / Phase Four

Phase Four

Phase Four develops radio-frequency (RF) plasma thrusters that operate without electrodes, eliminating a primary failure mode of traditional Hall-effect and ion thrusters. The Maxwell thruster offers a lower-cost, more reliable in-space propulsion option for small and medium satellites.

Founded
2015
Headquarters
Hawthorne, CA
CEO
Beau St. Clair
Headcount
50+
Total Funding
$30M+
Latest Valuation
~$100M
Status
private

Products

Maxwell thruster
https://phasefour.io

Funding History

RoundAmountValuationLead InvestorsDate
Series B$15M~$100MLockheed Martin VenturesJul 1, 2024

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