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.

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!

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.

Submarine Supplier Days 2023

I attended Submarine Supplier Days 2023 in Washington, D.C. March 7 and 8. It is an opportunity for companies contributing to building the latest attack and ballistic missile submarines to get together. The two big programs are for the Columbia Class fleet ballistic missile submarine and the Virginia Class attack submarines. Australia will be buying four of th e latter. I attended the meeting to introduce people to the potential of PFRC as a power plant for future submarines. The first day was a series of presentations on the latest submarines.

On the next day we visited the offices of our N.J. U.S. Representatives and Senators to gain their support for the submarine programs. Here is the inside of the Senate office building with its Calder sculpture.

It was fun to meet people building the submarines. One company in New Jersey has a sole source contract to weld components of the submarines. Each weld is signed by a welder so it can be traced back should a problem arise.

I learned that there are major problems with materials supply and with finding workers to build the submarines. Lead times on some materials can be 80 months. The issues of on-again/off-again production were also discussed. We all agreed, as did the Congressional and Senate staffers, that continuing resolutions were bad.

You can get our submarine brochure here.

Ford Mach-E on the Road

One of the biggest concerns people have with electric vehicles is charging. We’ve taken our Mach-E on two trips with different approaches to charging. Our experience is with a rear-wheel drive Mach-E with the extended range battery. Its EPA range is 303 miles.

The first was from Princeton to the Berkshires, then to Boston and then back to Princeton. The trips were made without any charging on the way. We used Level 2 chargers at our destinations. The Williams Inn, in Williamstown, had ChargePoint chargers, as did the Cambridge Marriott in Kendall Square in Cambridge, MA. At the Cambridge Marriott, there are ChargePoint chargers in the garage used by the valets. The valets are willing to plug your car in as long as you have a ChargePoint card.

The picture blow shows our current mileage.

The most recent trip was from Princeton to Pittsburgh. The one-way distance of 330 miles necessitated charging on the road. We used the Ford app, which showed two stops. We didn’t follow its plan. Instead, we broke the trip into two segments each way with one charging stop. Prior to the trip we tested the high power charging at a local EVGo station.

In both directions we stopped at the Electrify America charging station at 1098 Harrisburg Pike in Carlisle. It was only 2 miles from the highway at a location with the Sheetz convenience store. There were two 350 kW chargers and two 150 kW chargers. Here is the station on the way to Pittsburgh.

It took about 20 minutes to charge from 30% to 80%. We charged until Apple Maps said we had 20% battery margin at our destination. In both directions we ended up with about 15% margin. In Pittsburgh we did destination charging at the Forbes Tower garage. The garage was $22 for 24 hours and charging was free. It was a short walk from the Residence Inn.

On the way to Pittsburgh we were joined at the charging station by two Ford F-150 Lightning trucks. On the way back, we were joined by another Mach-E.

The Electrify America stations were seamless. We have 250 kWh of free charging from Ford. The station knew all about the free charging and we didn’t have to pay or do anything else to be reimbursed. It was simply plug and charge.

PlugShare was the most reliable way to find charging stations.

We drove a Tesla Model 3 as a Hertz rental In Chicago. We charged once at a SuperCharger. It worked very well! I’d say the Electrify America experience was its equal.

Aerospace Engineering Winter Internship

I worked on two projects during my winter internship at Princeton Satellite Systems: a two-stage-to-orbit (TSTO) launch vehicle design proposal related to the NASA Space Launch System (SLS) and a satellite conjunction maneuver demo. These both used the Spacecraft Control Toolbox for MATLAB.

One of the main ideas behind the TSTO launch vehicle project is to propose an all-liquid variant of the SLS. Currently, the SLS first stage is mostly powered by two solid rocket boosters (SRB) upgraded from the Space Shuttle SRBs. However, our proposal is to replace the two SRBs with five liquid boosters (LB), each mated with an RS-25 engine. The second stage would remain the same. Using MATLAB, I analyzed the launch and trajectory performance of both variants and found similar performance. Additionally, the total mass of the all-liquid SLS variant would be approximately two-thirds the mass of the SRB-powered spacecraft. An approximate CAD model of the all-liquid SLS version is shown below.

In addition, the LBs can be used independently to power smaller high-performance TSTO launch vehicles that carry around 8,000 kg of payload to low earth orbit. Trajectory plots and a preliminary CAD model are shown below.

My other project this internship was to help out with a satellite conjunction avoidance demo with Ms. Stephanie Thomas. The goal was to create a solution in MATLAB to identify potential satellite-debris conjunctions and develop a method/algorithm to avoid the conjunctions. I mainly worked on testing the code and relevant functions and providing feedback about the solution’s comprehensiveness.

Overall, I greatly enjoyed this internship and the opportunity to work at PSS. I saw firsthand how even a small company can make significant contributions to aerospace and engineering through diverse interests yet specific, impressive skill sets.

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.