SPACE INDEX COMPANIES INSIGHTS SECTORS PRODUCTS NEWS BLOG ANSWERS RESEARCH ABOUT FOR COMPANIES BUILD / 2026.06.03
Eta Space logo Eta Space Develops cryogenic propellant management systems for in-space storage, transfer, and refueling, and liquid hydrogen infrastructure for terrestrial energy applications. vs Phase Four Developed electrodeless radio-frequency and multi-mode electric propulsion systems for satellites Phase Four logo
HEAD-TO-HEAD1 shared sector
Eta Space Phase Four
Founded 2019 2015
Headquarters Rockledge, Florida, USA Hawthorne, California, USA
Type private private
Status operating closed
Employees 10 5
Total funding $27.2M $35.8M
Latest round Grant Series C
Sectors Space Transportation & Logistics, Lunar Services, Space Propulsion Space Propulsion, Satellite Components & Subsystems
Products listed 6 4
Federal contracts
Launches
Leaders listed Dr. William Notardonato Steve Kiser, M. Umair Siddiqui, Simon Halpern
News mentions 0 0
SHARED SECTORS
FREQUENTLY ASKED

How do Eta Space and Phase Four compare?

Both companies work in Space Propulsion. Eta Space was founded in 2019 and Phase Four in 2015.

Which is larger, Eta Space or Phase Four?

Eta Space reports the larger workforce, with 10 employees versus 5.

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