Phase Four

Electric propulsion for the new space economy

Satellite PropulsionFund I ✦ Exited

Next generation electric propulsion solutions for small satellites. Addressing the demands of rapid proliferation of satellite constellations.

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At a Glance

Latest Round$12.9M Series C (2025)

Founded2015

HeadquartersHawthorne, CA

Latest MilestoneSep 2025: Propulsion assets acquired by Quantum Space for space mobility missions

Quick Facts

SectorSatellite Propulsion

VVC FundFund I

Founded2015

HeadquartersHawthorne, CA

Status✦ Exited

Sector Context

Why Satellite Propulsion matters.

Small satellite constellations require affordable, reliable propulsion. The small satellite propulsion market is projected to grow to $6B by 2030 as mega-constellations proliferate.

Funding History

Series C

$12.9M

2025Led by Artemis Group Capital

Series B

$26M

2021Led by New Science Ventures

Key Milestones

Sep 2025Propulsion assets acquired by Quantum Space for space mobility missionsSource

Apr 2025Awarded $14.9M DARPA contract for air-breathing electric propulsionSource

Jan 2025Closed first tranche of Series C led by Artemis Group CapitalSource

Nov 2024Partnered with University of Oklahoma on iodine propulsion researchSource

Jul 2024Partnered with Redwire to build Hall Effect ThrustersSource

Phase Four Partners with Redwire to Expand Space Propulsion Offerings and Deliver Hull Effect Thrusters

VVC Fund I portfolio company, Phase Four, a leading provider of next generation electric propulsion solutions for satellites, proudly announced the signing of a strategic cooperation agreement with Re...

Aug 1, 2024

DARPA Awards Phase Four $14.9M Contract to Develop Air Breathing Electric Propulsion for Very Low Earth Orbit Operations

VVC portfolio company, Phase Four, a leading provider of next generation electric propulsion (EP) solutions for satellites, was awarded a $14.9M contract by the Defense Advanced Research Projects Agen...

Apr 4, 2024

Phase Four Secures a Coveted Spot in the Hyperspace Challenge

Veteran Ventures satellite propulsion portfolio company, Phase Four, announced their selection as one of six companies (and one of three U.S.-based companies) to participate in the U.S. Space Force’s ...

Nov 8, 2023

Exit Details

✦Asset Sale

Acquiring EntitiesQuantum Space / Apex

DateSeptember 2025

Phase Four's multi-mode propulsion assets were acquired by Quantum Space for defense, civil, and commercial space mobility missions. Apex separately acquired the Hall-effect thruster technology. The company was written off, though potential future upside remains tied to the acquiring entities' success.

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