SPACE INDEX COMPANIES INSIGHTS SECTORS PRODUCTS NEWS BLOG ANSWERS RESEARCH ABOUT FOR COMPANIES BUILD / 2026.06.04
Phase Four logo Phase Four Developed electrodeless radio-frequency and multi-mode electric propulsion systems for satellites vs Revolution Space Develops in-space electric propulsion systems and advanced spacecraft solutions for commercial and defense satellite operators Revolution Space logo
HEAD-TO-HEAD2 shared sectors
Phase Four Revolution Space
Founded 2015 2014
Headquarters Hawthorne, California Charlestown, Massachusetts
Type private private
Status closed operating
Employees 5 38
Total funding $35.8M $100.8M
Latest round Series C Venture
Sectors Space Propulsion, Satellite Components & Subsystems Space Propulsion, Satellite Components & Subsystems
Products listed 4 1
Federal contracts
Launches
Leaders listed Steve Kiser, M. Umair Siddiqui, Simon Halpern Darren Garber, PhD, Darren Womacks, Paul Richards
News mentions 0 2
SHARED SECTORS
FREQUENTLY ASKED

How do Phase Four and Revolution Space compare?

Both companies work in Space Propulsion, Satellite Components & Subsystems. Phase Four was founded in 2015 and Revolution Space in 2014.

Which is larger, Phase Four or Revolution Space?

Revolution Space reports the larger workforce, with 38 employees versus 5.

Numbers refresh on every render against the live Space Index database. Federal contract data from USAspending.gov; launches from LaunchLibrary2.