# Fusion startups are back in the weapons business

> With climate VC money stalling, fusion companies are finding a second customer: the defense industry that started it all.
- Title: Fusion startups are back in the weapons business · TechCrunch
- Summary: With climate VC money stalling, fusion companies are finding a second customer: the defense industry that started it all. Fusion's national security roots…
- Keywords: fusion, defense tech, laser weapons, climate tech, venture capital, technology, startups, back, weapons, business, TechCrunch
- Source: TechCrunch — https://techcrunch.com/2026/09/13/fusion-power-startups-find-new-partners-in-the-defense-world
- Author: Tim De Chant
- Published: 2026-09-13T13:15:00+00:00
- Read time: 2 min
- Topics: fusion, defense tech, laser weapons, climate tech, venture capital, technology, startups
## Fusion goes back to its roots
Startups still want electrons on the grid, but many are now taking on defense work too. It is less a pivot than a homecoming.

> Fusion power is getting back to its roots.
## Born from the bomb
The field started when Cold War physicists looked for constructive uses of thermonuclear science. The 2022 ignition breakthrough happened at a facility that has served national security for 25 years.
## Climate money dried up
Venture dollars for climate tech have stalled, and fusion burns cash fast. Investors are relieved when a portfolio company finds a second wallet to open.
## Drones broke air defense
Systems built to stop piloted jets now face swarms of cheap plastic. One US ally spent a $3 million Patriot missile on a $200 consumer drone.

> Effective, but not very efficient.
## Lasers change the math
A laser fires repeatedly and cheaply off a generator or a ship's reactor, instead of burning one expensive missile per shot.
## Xcimer takes RTX money
The laser fusion startup got an investment from RTX Ventures, the Raytheon parent. In return, RTX gets to explore what those lasers can do for weapons.
## The biggest private laser
Denver-based Xcimer runs Phoenix, which it calls the largest privately owned laser system in the world. It is ten times weaker than a power plant needs, and still strong enough to interest defense buyers.
## Pacific Fusion signs with NNSA
Its new New Mexico demo site sits near Sandia and Los Alamos. The reactions there will be more powerful than what the government uses today for weapons experiments.

> It turns out that the facility that we're building also has utility in this world-leading defense application.
## No coincidence at all
Defense was "always on our mind," says co-founder Carrie von Muench. Her co-founder built the core tech after years at Sandia, Livermore, and the NNSA.

> Defense applications were always on our mind.
## Key takeaway

Fusion's national security roots never went away, and now they are paying the bills while the grid dream is still decades out.