Zephyr Fusion

What do they actually do

Zephyr Fusion is an early-stage YC Fall 2025 startup developing an in‑orbit fusion power source—a compact, magnetic‑confinement system intended to deliver megawatt‑class electrical power for spacecraft and orbital platforms. They do not have flight hardware or an in‑orbit demo; the two‑person team in San Diego appears focused on R&D, simulations, lab prototyping, and partner outreach YC profile company site.

Near‑term work centers on validating the confinement and power‑conversion approach on the ground and preparing for a flight demonstration. A deployed unit would require plasma confinement, fuel handling, power conversion, heat rejection, satellite bus integration, launch qualification, and remote operations YC profile.

Who are their target customer(s)

• Large satellite manufacturers and constellation operators: They need continuous, high‑density power for bigger payloads but are constrained by solar array size/mass, intermittency, and battery limits, which cap instrument power without major launch mass increases YC profile company site.
• In‑orbit manufacturers and materials processors: Running furnaces/heaters and continuous production requires steady high power; current options force low throughput or make some processes impractical YC profile company site.
• Operators of high‑power electric propulsion (tugs, cargo transports, deep‑space probes): Available electrical power limits thrust and mission timelines; more onboard power would shorten trips or move heavier payloads YC profile company site.
• Orbital infrastructure providers (stations, depots, hubs): Scaling services and rendezvous operations needs reliable compact power without huge arrays or frequent resupply; current solutions add mass, surface area, or operational complexity YC profile company site.
• Government, defense, and research programs with high‑power experiments: They need dependable, high‑density power where solar isn’t practical; alternative nuclear options face long lead times and regulatory/political hurdles YC profile company site.

How would they acquire their first 10, 50, and 100 customers

• First 10: Pursue co‑funded ground demonstrations and shared on‑orbit demo plans with a few government research programs, one or two defense/space primes, and select commercial satellite or in‑orbit manufacturing teams; include dedicated integration support to reduce risk.
• First 50: Turn pilot results and flight demos into references and a repeatable offer: standardized integration kits, an engineering playbook, and lease or power‑by‑the‑hour contracts; bundle deployments with chosen launch and integration partners to simplify procurement.
• First 100: Industrialize production and sales via manufacturing/supply‑chain partners, introduce tiered service/insurance and spares, and expand through channel sales with satellite integrators, launch providers, and government contracting vehicles.

What is the rough total addressable market

Top-down context:

Directly relevant near‑term market: space power supply systems, sized in the low single‑digit billions today with modest growth Fortune Business Insights. Larger adjacent markets (in‑space manufacturing and space infrastructure) are much bigger on paper but only partially addressable if MW‑class orbital power is proven and qualified MarketsandMarkets Fortune Business Insights.

Bottom-up calculation:

Illustrative: if 10–30 high‑power platforms per year globally adopt MW‑class onboard power within 3–7 years, at $30–150M per unit (hardware, integration, support), that implies roughly $0.3–$4.5B in annual serviceable market once flight‑qualified.

Assumptions:

• Flight‑qualified demo and regulatory acceptance enable early commercial adoption on select platforms.
• Customers are willing to pay $30–150M per MW‑class unit compared to large solar+batteries or fission alternatives.
• 10–30 suitable missions per year materialize in the timeframe (government, primes, stations, tugs).

Who are some of their notable competitors

• Helicity Space: Startup developing compact fusion drives for space propulsion and power; pursues similar high‑density, continuous power goals and has NIAC‑related work site NASA NIAC.
• Westinghouse (eVinci): Established microreactor (fission) adapted for space; a nearer‑term, factory‑built alternative for compact long‑duration orbital power eVinci in Space NASA/DOE contract news.
• BWXT / Lockheed JETSON consortium: Defense and industrial partners developing small fission reactors for spacecraft power/propulsion under AFRL’s JETSON program—direct competition for compact space power BWXT.
• NANO Nuclear Space: Startup exploring micronuclear reactors and a space division; positions fission microreactors as alternatives to fusion modules for orbital power company.
• Avalanche Energy: Compact fusion startup that lists space as an application; if they achieve flight‑qualified units, they would compete for in‑orbit power customers space applications.