SPACE INDEX COMPANIES INSIGHTS SECTORS PRODUCTS NEWS BLOG ANSWERS RESEARCH ABOUT FOR COMPANIES BUILD / 2026.06.03
Impulse Space logo Impulse Space Designs and operates orbital transfer vehicles that move payloads between orbits using high-thrust chemical propulsion, delivering to GEO in under a day. vs Phase Four Developed electrodeless radio-frequency and multi-mode electric propulsion systems for satellites Phase Four logo
HEAD-TO-HEAD1 shared sector
Impulse Space Phase Four
Founded 2021 2015
Headquarters Redondo Beach, California, USA Hawthorne, California, USA
Type private private
Status operating closed
Employees 292 5
Total funding $895M $35.8M
Latest round Series C Series C
Sectors Space Transportation & Logistics, Satellite Manufacturing, Space Propulsion Space Propulsion, Satellite Components & Subsystems
Products listed 5 4
Federal contracts
Launches
Leaders listed Tom Mueller, Eric Romo, Kevin Miller Steve Kiser, M. Umair Siddiqui, Simon Halpern
News mentions 3 0
SHARED SECTORS
FREQUENTLY ASKED

How do Impulse Space and Phase Four compare?

Both companies work in Space Propulsion. Impulse Space was founded in 2021 and Phase Four in 2015.

Which is larger, Impulse Space or Phase Four?

Impulse Space reports the larger workforce, with 292 employees versus 5.

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