Princeton Satellite plan to generate pulses of net power fusion within 7 years

Princeton Satellite system is creating a direct drive fusion propulsion and power systems for a phase II NASA NIAC study. They have follow up government studies to develop the superconducting magnets and other components.

They are using radio frequency heating to reach fusion conditions. They need helium 3 which is scarce. There is enough helium 3 for some small space missions but would not be able to scale until there is more helium 3. Also, the cost would not be initially competitive. They are looking at high value niches.

It is a lot easier to make a fusion rocket versus a fusion power plant. Shorter pulses for fusion for propulsion is simpler than constantly generating power.

Princeton Satellite System has novel antenna configurations.

Direct fusion drive or dfd is a new type of rocket engine made of a fusion reactor powering a plasma rocket. It is different from many other nuclear fusion technologies because this single fusion engine can generate both propulsion and electricity to power its payload.

The DFT engine is made of a linear array of coaxial magnets with a pair of smaller but stronger mirror magnets at the ends a fusion region. It is centered within the magnet array while cool plasma flows around it to extract energy. This fusion region is about the length of a surfboard and holds very hot plasma that spins like a motor. Antennas surrounding the engine create a novel radio frequency heating mechanism which has tuned to particular fuel ions and creates a current in the plasma. The plasma ions get pumped up with increasing energy cycles until the ions become hot enough to fuse once the ions fuse they create new very energetic particles called fusion products. These particles follow paths that take them in and out of the cool plasma layer as they orbit the magnetic field lines with each pass the fusion products lose energy until they get captured by the open field lines and shoot out the back of the engine. This takes just a few milliseconds. The mirror magnet at the end of the engine converts this electron thermal energy into ion kinetic energy. This creates thrust just like a regular rocket nozzle extra heat from the fusion reaction is converted into electricity providing power for scientific instruments and communications.

The ISP is about 20,000. 5 to 10 newtons are generated per megawatt of fusion power. They are looking at 1 to 2 megawatts for the initial space system. This would thus produce 10 to 20 newton using a 2 megawatt system.

They want to get their machine cycle down to 3 years. They want to complete the system for less than $100 million.

They believe they can also make a pure energy generation system. They refer to this as closed loop mode.

There next device should reach fusion in around 2023-2025.

Princeton Field Reversed Configuration (PFRC) is a novel plasma heating method that can lead to a very small fusion reactor. With one end open to space, PFRC becomes the Direct Fusion Drive (DFD), a fusion-powered rocket engine that could enable new robotic and human missions. The PFRC magnetic device would create a cigar-shaped plasma—the superhot, electrically charged gas that fuels fusion reactions. The device uses an innovative method to stream cool ions around the plasma fusion region to remove the fusion ash and efficiently produce thrust and electricity simultaneously. Propulsion would come from this stream of ions, which are heated by the energetic fusion exhaust as they travel along the engine and then blast into space through a magnetic nozzle.

Princeton Satellite Systems (PSS) licensed the PFRC patents from Princeton University, the contractor for Princeton Plasma Physics Laboratory (PPPL), for space propulsion applications. Since the execution of the license agreement, additional patents have issued and additional funding for research at PPPL was obtained via grants from NASA’s Innovative Advanced Concepts (NIAC) program. In addition, the licensee was selected in mid-2017 for two NASA Small Business Technology Transfer (STTR) awards on NASA’s new topic, Advanced Nuclear Propulsion, in partnership with Princeton University.

Space applications for DFD include high power Earth satellites, deep space propulsion, and electric power for robotic and human bases throughout the solar system, including the moon and Mars. PSS is already looking far beyond Mars, as DFD would enable ambitious robotic solar system missions at far less cost than current technology allows. There are many important terrestrial applications for DFD as well, including portable power for emergencies, remote power for villages and towns that are not on the grid, and forward and mobile power for the military. In addition, PFRCs could be used in a modular fashion for ordinary power stations that can be built incrementally without the huge capital investments needed for current technology including cogeneration plants. A full-size plant would fit on a tractor trailer easily transportable by road, rail or plane. It could provide power to remote villages that currently rely on diesel power with fuel delivered by light planes. It could also provide forward power for military forces to power the planned all-electric Army Brigade Combat Team or Navy surface and underwater combatants.