PSS and the Princeton Plasma Physics Lab are collaborating on a new fusion technology. Direct Fusion Drive is a 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 and high specfic 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 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 a NASA Innovative Advanced Concepts grant. Our 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:

  • 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
  • 550 AU gravity lens telescope

In all cases, DFD reduces trip times and increases payload capability and science return!

Publications and News:

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

  • “In Space Startup Method for Nuclear Fusion Rocket Engines,” Paluszek, M., Ham, E., Cohen, S., and Razin, Y. Patent Pending, August 2013, Number 20150055740.
  • “Method To Reduce Neutron Production in Small Clean Fusion Reactors,” S. Cohen, Patent Pending, May 2013, Number 2013191779.
  • “Method To Produce High Specific Impulse and Moderate Thrust From a Fusion-Powered Rocket Engine,” S. Cohen, G. Pajer, M. Paluszek, Y. Razin, Patent Pending, May 2013, Number 20140311902.