Week in Space Data, every Friday.
Phase Four develops radio-frequency plasma thrusters with flexible propellant options for smallsat and medium-class spacecraft propulsion.
DEFUNCTPhase Four developed radio-frequency electric propulsion for small satellites; in September 2025 it sold its Hall-effect thruster technology to Apex and its multi-mode propulsion technology and Hawthorne, California test facility to Quantum Space.
Phase Four developed radio-frequency electric propulsion for small satellites; in September 2025 it sold its Hall-effect thruster technology to Apex and its multi-mode propulsion technology and Hawthorne, California test facility to Quantum Space.
Not scored The Space Score is a 0 to 1000 snapshot of a space company's size and activity, relative to the other companies we track. It combines size (headcount, market value and revenue, 30%), U.S. federal space contracts (20%), equity raised (15%), momentum (15%) and, for launch companies, orbital launches (20%), so it leans heavily on size. It is descriptive: not a forecast, a rating or investment advice.
This company is not in the Space Score roster. Only company profiles with an active or pre-revenue status are scored.
Inputs measured 2026-10-14 (UTC) · methodology v6 · Who is scored, and why
Sources: Founded, Status, Legal name
For information only, not investment advice. SpaceNexus is not a registered investment adviser, broker or dealer, and nothing here is a recommendation to buy, sell or hold any security. Data may be delayed, estimated or incomplete; check the source before acting. Full disclaimer
4 private rounds on record. Debt, grants, state capital, owner funding and acquisitions are listed under Funding history by class and not added in.
Radio-frequency plasma thruster offering propellant flexibility and high performance for LEO and beyond.
Checking for a discussion…
Compiled Oct 14, 2026 from 5 public records. Every figure links the record it comes from.
Form D notices
4 offerings reported on Form D
Latest filed Jan 17, 2025; first sale Jan 6, 2025; 1 of them last updated by an amendment (D/A)
Each offering counts once: a later amendment (Form D/A) replaces its original. Form D names no round label and no investors. Filings for a merger or SPAC deal are left out.
Latest sourced round
Series C (first close): $12.9M
Reported on Form D filed Jan 17, 2025; the date shown is the first sale
Source: SEC EDGAR
First sale Jan 6, 2025
Sourced rounds on record
4 rounds, $43.6M disclosed
Every round has a disclosed amount
Published rounds with a source link only, on the same rules as the funding tracker. Each round links the source that states its figure; amounts in other currencies are converted to dollars at the rate shown on the funding tracker.
APA
SpaceNexus. (2026, October 14). Phase Four: Company dossier [Data set]. Retrieved October 14, 2026, from https://spacenexus.us/company-profiles/phase-four
Chicago
SpaceNexus. "Phase Four: Company dossier." Data as of October 14, 2026. Accessed October 14, 2026. https://spacenexus.us/company-profiles/phase-four.
BibTeX
@misc{spacenexus_phasefour_2026,
author = {{SpaceNexus}},
title = {{Phase Four}: Company dossier},
year = {2026},
month = oct,
howpublished = {\url{https://spacenexus.us/company-profiles/phase-four}},
url = {https://spacenexus.us/company-profiles/phase-four},
urldate = {2026-10-14},
note = {Data as of 2026-10-14; each fact links its primary source}
}