Nuclear Fusion Propulsion

PSS and the Princeton Plasma Physics Lab are collaborating on a new nuclear fusion technology. Direct Fusion Drive is a revolutionary direct-drive, fusion-powered rocket engine. Compact and clean-burning, each 1-10 MW Direct Fusion Drive (DFD) engine can produce both power and thrust with high specific power. Power and propulsion are both generated from a single engine, which shortens trip times and increases capability for a wide variety of space missions: robotic missions to the outer planets, human missions to the moon or Mars, missions to near interstellar space.

DFD is based on the Princeton Field-Reversed Configuration reactor (PFRC), a technology developed by Dr. Sam Cohen of PPPL. The reactor employs a unique “odd-parity” RF heating method, producing a steady-state, closed-field configuration with a highly efficient current drive. The PFRC-2 experimental machine is currently in operation at PPPL, a plasma pulse is shown below. Read more on the PFRC technical papers page!


PFRC-2 has been supported by the Department of Energy, and now DFD research is being supported by a NASA Innovative Advanced Concepts grant and two NASA STTRs. Our NIAC context mission is a Pluto orbiter and lander that are delivered in just 4 years, and can send back the equivalent of HD video!

We have analyzed DFD for many missions and applications:

  • Human Mars orbital mission
  • Deploying the James Webb Telescope to a Lagrange point
  • Asteroid deflection
  • Jupiter Icy Moons Mission
  • Pluto orbiter and lander
  • Alpha Centauri
  • 600+ AU gravity lens telescope
  • Mobile and modular terrestrial power

In all cases, DFD reduces trip times and increases payload capability and science return! For the latest updates on our research, check out our DFD blog posts.

Publications and News:

PSS has licensed three patents from PPPL for applying PFRC to space propulsion, and more are in the works:

  • “Method To Reduce Neutron Production in Small Clean Fusion Reactors,” S. Cohen, US Patent Number 9,767,925 issued 9/19/2017.
  • “Method To Produce High Specific Impulse and Moderate Thrust From a Fusion-Powered Rocket Engine,” S. Cohen, G. Pajer, M. Paluszek, Y. Razin, US Patent Number 9,822,769 issued 11/11/2017.
  • “In Space Startup Method for Nuclear Fusion Rocket Engines,” Paluszek, M., Ham, E., Cohen, S., and Razin, Y. Patent Pending, August 2013, Number 20150055740.

Princeton Satellite Systems has a doing-business-as name for terrestrial fusion applications: Princeton Fusion Systems. Visit our sister site for more information on PFRC!