Final Titan Aircraft Paper Published in Acta Astronautica

The final version of our paper, “Nuclear Fusion Powered Titan Aircraft,” by Mr. Michael Paluszek, Ms. Annie Price, Ms. Zoe Koniaris, Dr. Christopher Galea, Ms. Stephanie Thomas, Dr. Samuel Cohen, and Ms. Rachel Stutz is now available, open access, on the Acta Astronautica website. As described in our earlier post, the paper discusses a mission to Titan using the Direct Fusion Drive on the transfer vehicle, and a Princeton Field Reversed Configuration reactor to power an aircraft, that could fly around Titan for years. The reactor allows for high-power instruments, some of which were first proposed for the NASA Jupiter Icy Moon Orbiter Mission. The paper was first presented at IAC 2022 in Paris.

Two key figures were updated from the preprint version of the paper – Figure 11 and Figure 12, showing the power flow and mass breakdown of the PFRC for the electric aircraft. The earlier figures were from a larger version of the engine. The final engine design produces 0.5 MWe and has a mass of 1006 kg. This is now consistent with the system masses presented in Table 6. Vehicle Power and Payloads.

Universe Today has published an article about our mission study, “What if Titan Dragonfly had a fusion engine?”

PSS appears on the Space Business Podcast to talk about nuclear fusion propulsion

Mike Paluszek and I appear on the newest episode of Space Business Podcast to talk about nuclear fusion propulsion, Direct Fusion Drive, and the Princeton Field-Reversed Configuration (PFRC) concept!

We had a great conversation with the host of this podcast, Rafael Roettgen, who asked us thoughtful questions. In this episode, we discuss topics such as: the future of space propulsion, the history and benefits of field-reversed configurations and how they compare with other fusion reactor concepts, mass and power budget considerations of a fusion rocket, and the road ahead for research and development to get us to a prototype for space. We additionally talk about terrestrial (on earth) applications of the PFRC concept as a globally-deployable power plant for remote areas and look forward to even more futuristic space concepts that could follow after the PFRC.

You can access this episode on podcast platforms including Apple Podcasts and Spotify as well as directly on their website. Enjoy!

Our Titan Mission Paper preprint is now online in Acta Astronautica

Our IAC paper on a fusion-powered Titan mission is now available in preprint on Acta Astronautica online, with the final version to come soon! Our mission concept utilizes two PFRC reactors: one configured as a Direct Fusion Drive rocket for the journey to Titan, and a second configured as a power source for the electric aircraft that will survey Titan. The paper includes a detailed design of the aircraft and analysis of optimal entry into the atmosphere and landing on the moon’s surface.

https://doi.org/10.1016/j.actaastro.2023.04.029

Fusion-propelled transfer vehicle shown in orbit around Titan. The transfer vehicle would serve as an orbital science platform and communications relay to Earth. The 2.4 MW fusion reactor provides 1.4 MW of thrust power and 100 kW of electric power.
Fusion-powered electric aircraft for Titan science exploration. The aircraft has six ducted fan engines. The onboard reactor provides 500 kW of electric power.

Crowdfunding for fusion development closing at the end of April

Our crowdfunding opportunity at is scheduled to close at the end of the month. We’ve raised over $100K so far to support fusion development and specifically, the PFRC-2 experiment at Princeton Plasma Physics Laboratory as we close in on our ion heating milestone. This is the last two weeks to invest in our raise on SpacedVentures!

Deal closes in 14 days

ARPA-E Energy Innovation Summit 2023

At the end of March, we attended the ARPA-E Energy Innovation Summit in National Harbor, MD. At the Summit we presented our work on power electronics tailored for fusion systems under an ARPA-E GAMOW grant. It was a great experience to network with many other awardees of ARPA-E grants working on innovative energy projects and learn about the power electronics needs of potential customers so we could design our boards to these specifications. Shown below is our Summit booth which was run by PSS Mike Paluszek and me.

Our booth contains prototype circuit boards developed by PSS and our collaborators at Princeton University (the Princeton Power Electronics Research Lab), along with flyers and other learning materials. The posters mounted behind us describe the work done by us and our collaborators: the Princeton Power Electronics Research Lab, UnitedSiC (now Qorvo), and the National Renewable Energy Laboratory (NREL).

Breakout sessions included panels on: future plans for inertial fusion energy, nuclear & materials, rethinking the nuclear waste challenge, and scaling up innovations for impact in the private sector with the ARPA-E SCALEUP program. Dr. Neil deGrasse Tyson gave a talk at the Summit!

The pdfs of the trifold and posters at our Summit booth are shown below. If you have any power electronics requirements for your systems, please contact us at info@princetonfusionsystems.com!

Young Women’s Conference @PPPL

Stephanie and I attended the YWC conducted by PPPL at Princeton University on March 16, 2023. This conference introduces middle-school and high-school-aged girls (in 7th to 10th grades) to women scientists and engineers and the wide breadth of careers available to them in these fields. Prominent women scientists and engineers from around the region spend the day with the girls engaging them in different variety of formats that include small-group presentations, hands-on activities, a keynote address, and a chemistry demo. This event is a great motivation for the girls to choose STEAM as their career.

We had a booth that demonstrated our work in various fields like coding books such as MATLAB Recipes and Machine Learning that have been written by Michael Paluszek, The President of Princeton Satellite Systems and Stephanie Thomas,Vice President of Princeton Satellite Systems.

We had 3D printed models of the Princeton Field reversed Configuration (PFRC), a Poster of Direct fusion drive, Spectroscopy diagnostic poster that demonstrated the visible and X-ray diagnostics that are performed to predict the electron temperature, impurities, and how these vary with other experimental parameters such as pressure, magnetic field and RMF-heated power in PFRC.

I demonstrated how visible light can be split into different wavelengths using a hand-held spectroscope. Visible light waves are electromagnetic waves. We see these waves as the colors of the rainbow. Each color has a different wavelength. Red has the longest wavelength, and violet has the shortest wavelength. These different colors of waves together make white light. The girls enjoyed observing different wavelength colors using the handheld spectroscope It was fascinating to see around 800 students after the Pandemic for this conference.

Lastly, we enjoyed the keynote talk by Dr. Liz Hernandez-Matias. Sr. Educational Specialist, CienciaPR.

New paper published on analyzing and mitigating pulse-pile-up artifacts in PFRC-2 plasma x-ray spectra

A new paper,Analysis and Mitigation of Pulse-Pile-Up Artifacts in Plasma
Pulse-Height X-ray Spectra
” by Taosif Ahsan and our team has been published open-access in MDPI Plasma. It describes the implementation of an algorithm, the two-photon trapezoidal uncorrelated-pulse model, to improve analysis of x-ray spectra emitted from PFRC-2 plasma. This model was developed to reduce artifacts in x-ray spectra caused by pulse pile-up, PPU (the phenomenon where x-ray photons are recorded nearly simultaneously so that only one x-ray photon is recorded with a combined energy), and diagnose the tail region to see if it is a pulse-pile-up artifact or if it has physical origins.

Four scenarios are shown to illustrate pulse pile-up. The top left plot has two trapezoidal pulses overlapping close enough so that the registered peak (energy) is the addition of the peaks of the individual pulses. The bottom right plot is a case where the individual peaks are detected and so pulse pile-up is not an issue. The top right and bottom left plots are in-between cases where there is enough overlap to result in a combined pulse with an intermediate energy recorded. This figure is described in the published paper.
More figures from the published paper showing the successful mitigation of pulse pile-up using the model derived in the paper.

Experiments on the Princeton Field-Reversed-Configuration (PFRC-2) device explore nearly pure, ca. 99%, partially ionized, warm hydrogen plasmas. For these, great interest lies in the tails of the X-ray spectrum. The tail region is important as an electron temperature in the PFRC can be estimated by fitting a Maxwellian distribution. Small tails of high-energy electrons in the energy distribution (EED), even comprising less than 1% of the plasma density, can have large effects on the resistivity, stability, and reaction rates of the plasma.

This paper is a step toward understanding how PPU affects the tail region of spectra for detector-formed trapezoidal pulses. Here we focus on relatively low count rate (≤0.1/deadtime) spectra where primarily only two-photon pile-up needs to be considered. Extension of this work to multi-photon pile-up will be necessary to develop an analytical tool to diagnose and mitigate pile-up effects in the tail regions of higher count-rate spectra.

Winter Power Electronics Internship

At MIT, we are given the month of January off from classes to pursue our own interests, whether they be career-oriented or hobby-based. During these five weeks, I have worked at PSS as a power electronics intern. My time at PSS has given me the opportunity to explore so many of the industry based applications of electronics and electrical engineering amongst some of the most innovative minds in the aerospace and energy industries. 

Within the GAMOW (Galvanizing Advances in Market-Aligned Fusion for an Overabundance of Watts) project, my work centered around helping redesign, assemble, and test a power load switch, the resulting prototype of which is shown above. Within this project, I received a wide array of experience ranging from 3D-modeling PCB boards with Eagle software, to physical board assembly, to designing testing procedures for the completed board. Initially, I worked on redesigning the load switch PCB to reduce loop currents and noise. My next steps were to source and order all needed components for in-house assembly. During the assembly process, I worked with both a soldering iron and hot air rework station to assemble surface mounted devices (SMDs) and through-hole components. 

Raspberry Pi setup for PWM

I also dipped into some software based components of the project, programming in C and Python to create hardware based signals to our desired testing specifications. Specifically, I was aiming to make Pulse Width Modulation (PWM) signals of a specific duration for the Raspberry Pi to output. This led to various tests on the outputs of the code, through the use of an oscilloscope (two PWM pulses on the oscilloscope are shown below). Ultimately, I had the chance to start testing the board in connection with a power supply and the Raspberry Pi’s program.

Moreover, I had the opportunity to dip into so many different branches of electrical engineering and project design. In attending meetings about all of the individual components of the massive GAMOW project, I saw how the team plans and executes each individual collaborative part of the project. This experience in the project process and cutting edge electrical project design as a whole have given me many insights into the professional world of electrical engineering.

PFRC Article in the Journal of Fusion Energy

Our latest paper, The Princeton Field-Reversed Configuration for Compact Nuclear Fusion Power Plants, is available in the Journal of Fusion Energy, Volume 42, Issue 1, June 2023. This paper is the first released in “The emergence of Private Fusion Enterprises” collection. A view-only version is available for free here.

Our paper gives an overview of the Princeton Field-Reversed Configuration (PFRC) fusion reactor concept and includes the status of development, the proposed path toward a reactor, and the commercialization potential of a PFRC reactor.

The Journal of Fusion Energy features papers examining the development of thermonuclear fusion as a useful power source. It serves as a journal of record for publication of research results in the field. This journal provides a forum for discussion of broader policy and planning issues that play a crucial role in energy fusion programs.

Producing Terrestrial Power with Helium-3 from Uranus using PFRC/DFD

Our latest paper on DFD applications, “A Fusion-Propelled Transportation System to Produce
Terrestrial Power Using Helium-3 From Uranus”, is now available from AIAA. This paper was part of the Future Flight Propulsion track and AIAA SciTech 2023. For those with AIAA membership, there is a video recording of the presentation as well! Download the paper here.

Our goal with this paper is to create a framework within which we can study the potential cost of electricity produced on Earth using helium-3 mined from Uranus. The scarcity of terrestrial helium-3, along with the radioactivity of methods to breed it, lead to extraterrestrial sources being considered as a means to enable clean helium-3 fusion for grid-scale electricity on Earth.

This paper builds on the work of Bryan Palaszewski who has published numerous papers on mining the atmospheres of the outer planets. Palaszewski’s work assumed fission-based power and propulsion systems, with a much lower (worse) specific power than we anticipate from a PFRC-based Direct Fusion Drive. We consider both transport and mining vehicles that are instead fusion-powered, including a fusion ramjet. This ramjet may be able to be both the mining vehicle and the orbital transfer vehicle to bring the refined helium-3 to the interplanetary transport,

Components of a conceptual fusion-propelled and -powered Uranus atmospheric mining infrastructure

The results allow us to estimate levelized cost of electricity, LCOE, for the electricity produced on Earth as a function of assumed cost of the fusion transports and mining system, cost of the PFRC reactors, amount of helium-3 stored on each transport and numbers of trips per year, etc. You can learn more about LCOE from the NREL website. Uranus is likely the most economical outer planet for mining due to its lower gravity and radiation environment and high concentration of helium in its atmosphere, about 15%. We find that with our set of assumptions, the resulting cost of electricity could potentially be competitive with wind and solar.

Future work will include analysis of the fusion ramjet trajectories between mining and transfer altitudes, and research into sizing a mining payload using membranes and adsorption to separate the helium-3 from the helium, rather than depend on heavy cryogenic techniques.