Phase II NASA STTR on superconducting magnets selected!

We are pleased to announce that our Phase II STTR proposal, “Superconducting Coils for Small Nuclear Fusion Rocket Engines,” was one of 20 selected for award by NASA in this year’s round! The full list of winners is posted on NASA’s website.

Our briefing chart prepared as part of the proposal is shown below:Briefing chart

We will be building a testbed with a split-pair superconducting coil (two windings with a gap between them) and performing experiments to assess the impact of operating the magnets in the vicinity of the FRC plasma. Applications of the technology go beyond fusion reactors, for example science payloads and high-performance motors for hybrid electric aircraft.

My Summer Internship

The past 10 weeks at Princeton Satellite Systems have been a life changing experience. During my summer off from the University of Pennsylvania, I have worked as an intern for the company. This gave me the opportunity to learn from trailblazers in the industry and to be immersed in a community passionate and dedicated to the work.

I first heard of Princeton Satellite Systems at the Dawn of Private Space Science Symposium in 2017. After that, Mike graciously agreed to come speak for the Penn Aerospace Club in the fall and the Ivy Space Coalition Conference the next spring. Everyone in attendance was fascinated by the presentation and I felt so lucky that I would have the chance to learn so much more soon. Connections like these are what drive the aerospace community and as I expand my communication I hope to stay closely in touch with the people I came to know at PSS.

Through my work, I’ve been doing a lot of Matlab modeling: sizing the components for the Direct Fusion Drive engine, testing a rotating detonation engine, and MHD plasma simulation. The idea of these technologies enhancing propulsive power and efficiency is fascinating and has great potential for the future of space travel.

My summer at Princeton Satellite Systems has helped me to enhance my technical understanding and skills: I’ve definitely gained a ton of experience in Matlab, and all of my studying of plasma modeling should give me a head start in my fluids class next semester! I’ve also gained a much better understanding of how the professional world works. I got to help write and edit proposals, sit in on phone calls, and even attend the NIAC meeting at Princeton Plasma Physics Lab.

I think that there’s a great benefit in working at a smaller company. You are given plenty of real responsibility and see the changes happening in real time. I will definitely take the lessons I’ve learned this summer and apply them to my education as well as my future career as a mechanical engineer.

I am so grateful for this opportunity. Everyone has been so kind and helpful and patient. The time has flown by, and it definitely made staying in my little Princeton dorm with no air conditioning well worth it! I’ll miss coming in to work every day but I can’t wait to see all the big things that PSS accomplishes.


PSS Dress Code: What is “business casual”, anyway?

Our interns always ask us, “What’s the dress code?” Our dress code at the office is business casual – which according to Wikipedia is not that well defined! We are probably on the more casual side of business casual. Here are some guidelines:

What to wear:

  • Khakis, trousers, skirts, polos, button-down shirts, blouses, sweaters
  • Dark or colored denim trousers
  • Shorts and sandals are OK in the summer – we prefer to turn the thermostat up and save money on A/C!

What NOT to wear:

  • Ripped or faded jeans
  • Very short skirts or shorts
  • Leggings – leggings are not pants! Leggings should be treated as footless tights and always paired with dresses or tunics.
  • Camisoles/spaghetti straps – camisoles are not blouses!
  • Flip-flops or sad beat-up sneakers

Anyone working on hardware should wear closed-toe shoes and tie back long hair, as in any lab space.

A side comment: my husband is a tech executive in New York, and he wears what I call the “tech uniform” to work every day: dark jeans from Banana Republic, button-down shirt, brown dress shoes, and a navy blazer. Now, guys in tech get away with this, but probably not lawyers! As PSS is solidly in the tech regime, we definitely take a more casual approach to “business casual”!

Young Women’s Conference in STEM

Princeton Satellite Systems attended the Young Women’s Conference in STEM in at the Frick Laboratory on the Princeton University campus again this year. We had an exhibit with spacecraft hardware and software. This include 3D printed models of our fusion reactor core and a 2 stage to orbit launch vehicle, star and navigation cameras, a circuit board for driving a fusion reactor and a 3U CubeSat frame . We were also running a simulation of a Lunar Landing simulation.

We met many enthusiastic students this year! It seemed that there were more high school students than in past years. A budding plasma physicist asked how we fuel the Direct Fusion Drive engine. Another student, looking at our Lunar Lander simulation display, asked what is a quaternion! The disassembled reaction wheel was very popular.  Some students wanted a detailed explanation about how the motor worked. One student wanted to know the electrical details of our RF board. Several were interested in our Army iPhone app. One wanted to know if she could get it from the App Store.

Other attendees included Lockheed Martin, the FBI and the Princeton Plasma Physics Laboratory. Click on this image to see a video about the event.

It was a fun event, albeit exhausting given the four hours of continuous conversations. We do hope that we inspired some of the attendees to pursue careers in science, math and engineering!

Inter Ivy Space Coalition Meeting

Marilyn and I attended the first Inter Ivy Space Coalition Inter Ivy Space Coalition meeting at Yale University on April 6 and 7.

The meeting was attended by students with an interest in space from the Ivy League schools. Saturday consisted of talks by speakers from a wide range of organizations followed by an exhibition and a banquet. Jonathan Li of Yale was the driving force behind this excellent conference.

The Dean of Engineering of Yale opened the meeting talking about the Yale Undergraduate Aerospace Association. They have done a wide variety of space work including some very large rockets. One student later showed me the nozzle for their latest rocket.

Dr. Fuk Li of JPL, Director Mars Exploration Directorate, talked about Mars 2020. The mission with its very sophisticated rover, will look for indigenous life, study climate and geology and prepare for Exploration. One ambitious goal is to eventually return Mars samples. The challenge of the sample return is to not contaminate the Earth as in the movie The Andromeda Strain.

Prof. Alessandro Gomez of Yale gave a nice talk on electrospray thrusters. The thrusters will be very valuable for small satellite missions.

Suresh Kannan talked about Trustable Autonomous Aerospace Systems. He had great videos from Nvidia on autonomous car control systems and videos from Boston Dynamics showing their amazing robots.

Ellen Chang, co-founder of  Lightspeed Innovations is a former U.S. Navy Intelligence Officer and a graduate of the Naval Postgraduate School. She talked about the state of investment in space. She mentioned a couple of investments organizations, including IQT, which was started by the CIA! She said a key issue for space companies is that investors can’t wait 20 years for their return on investment.

I gave the next lecture presenting the latest results on our work on Direct Fusion Drive.

Artist rendering of DFD rocket engine

We’ve been able to reduce the mass of our RF and superconducting coil subsystems dramatically. We have completed the radiation heat transfer analysis of the reactor which shows that it isn’t a big problem. Conduction will provide the major heat loads.

Here is a recent shot in our experimental facility.

I included a  teaser slide on our two stage to orbit vehicle that we are proposing to NASA and DARPA. It would be inexpensive enough for companies and universities to own their own launch vehicle. It is fully reusable and could be launched at any convenient airport. It can also shuttle around the world at subsonic speeds. It is about the size of a private jet.

Alden Richards, founder of Space Machine Advisors, gave a fun talk on the space business. He insured the PanAmSat launch on which I worked. He said that the key for space profitability is dual use,

Jason Aspiotis of Finsophy talked about sources of funding for space. These include global sovereign funds that countries like Kuwait and Norway maintain. He  is a founder of  SpaceVault online banking and SpaceXchange.

Dr. Jonathan Arenberg of  Northrop-Grumman talked about the Chandra X-Ray telescope. He also talked about future missions for imaging exo-planets. Dr. Arenberg is second from the left on the linked page.

Ulisses Ortiz of  Space for Humanity talked about his plan to make sub-orbital flights available to anyone. People selected would make a commitment to using the publicity for a good cause.

Kari Love of  Soft Robotics gave a great talk on how to win contracts. She said you need to get to know people by going to conferences and responding to RFIs. She said you can make contacts by going to non-space events, like science fiction conventions. She recommended using professional illustrators for key graphics. Kari has a interesting background. She designed the Spiderman costume for the Broadway musical!

Dr. Lin Chambers Atmospheric Scientist at NASA/LaRC, gave the final talk of the day. Unfortunately, we were setting up our table for the networking fair so we missed her talk!

Princeton Satellite Systems had a table at the networking fair. The TV is showing a lunar landing simulation. We had a disassembled reaction wheel, a sun sensor, a navigation camera and a 3D printed model of our two stage to launch vehicle, Space Rapid Transit Mini.

We talked with many students. All of our discussions were interesting. I talked at length with an English major interested in space!

Scott Willoughby of Northrop-Grumman and Program Manager of the James Webb Space Telescope  gave an overview of the program in the after dinner talk.

Here are the speakers and student organizers.

We look forward to next year’s meeting! 

Lunar Landing Control System

The first soft moon landings were accomplished in the 1960’s by the Soviet Luna 9 and the U.S. Surveyor Spacecraft. These were followed by the U.S. Lunar Module landings during the Apollo program. The Soviets had their own LK Lander lunar lander for landing humans on the moon but it never flew. China’s Chang’e-3 landed on the moon on December 13, 2013. India plans to land the Chandrayaan-2 on the moon in 2018.  South Korea intends to land a spacecraft on the moon in 2020.

The U.S. Lunar Module was flown by a crew but had a digital computer that performed guidance, navigation and control. A great new book by Don Eyles, Sunburst and Luminary an Apollo Memoir explains how that was accomplished with a computer less powerful than those in toaster ovens today. Don played a key role in saving the Apollo 14 mission when an abort light appeared on the crew’s console prior to descent. Read the book for for the whole story.

NASA intended follow-ons to the Lunar Module that would have been fully automated for delivering materials to the moon in preparation for a permanent human presence. Unfortunately, those plans never materialized.

As we are always looking for new missions for testing our Precision Attitude Control System, we added guidance, navigation and control for lunar landings. We use a really simple guidance algorithm called 2nd order guidance. It is nothing more than a Proportional Derivative (PD) controller with the landing spot as a target. You can adjust the damping ratio and undamped natural frequency of the controller to mimic more sophisticated, “optimal” guidance algorithms. The 2nd order guidance works until the lander gets near the surface and then it switches to landing algorithm that hovers, nulling any remaining translational velocities and then descends to the surface. Lidar would be used as guidance. Once it is hovering it would need to search for a flat spot for landing. NASA has developed Hazard Detection Software for Lunar Landing that uses lidar. It is available for licensing from Caltech.

Here is one simulation in our Simulation Framework. Once the descent is initiated, the spacecraft reorients so that the main engine thrust vector is in the desired direction. The display on the left shows the attitude errors (the two boxes) and the throttle setting (which is zero during the attitude maneuver.)

A close up of the attitude display. Pitch and yaw are offsets of the green rectangle. Roll is rotation of the rectangle. This is quite primitive but it is easy to add your own displays if you know a little OpenGL!

Descent starts and the throttle is about 50% at this point. The two plots are of altitude and velocity. The maneuver starts at 15 km and the target is 600 km along track. The lander has solar panels on a two-axis gimbal and a high gain antenna, also on a two-axis gimbal.

The propulsion page shows two attitude thrusters firing and the main engine.

The spacecraft has landed! You can see the terminal descent phase on the altitude and velocity plots. The lunar surface is featureless because we have not added close up maps of the landing zone to the planet display.

The descent page shows the throttle settings. You can monitor the guidance force demand and simulated force.

This is the propulsion page. The attitude thrusters get very busy during the terminal descent phase. Note that we have a lot of fuel left! We could have hovered for quite some time.

The graphics are from our VisualCommander product that runs on Mac OS X.

This GN&C system is capable of autonomous flight from LEO all the way to the moon. It uses our Optical Navigation System, developed under a NASA Phase II SBIR for trajectory determination on the flight to the moon and lunar orbit entry.

For more information contact us directly!

PFRC Paper Accepted to Physics of Plasmas

Our colleague Eugene Evans of PPPL has had his paper, “Particle-in-cell studies of fast-ion slowing-down rates in cool tenuous magnetized plasma,” accepted for publication in Physics of Plasmas. The article is tentatively scheduled for the April 2018 issue. A quote from the reviewer:

The paper … is an interesting, well-written paper that uses PIC to build upon earlier direct numerical simulation methods based on molecular dynamics. The authors present a clearly written discussion of the scaling properties of slowing down theory to support their numerical studies. The authors do a very good job describing the simulation approach they take… Of particular note in the paper is the good agreement between their numerical data and the sub-thermal model even when the effective computational log(lambda) was on the order of 1…  the authors did not stop with their results but instead applied their conclusions to the FRC reactor, predicting that the neutron production rate is 100 times lower than a conventional DT Tokamak.

This paper is key to the low radiation levels claimed for our PFRC design, and hence the Direct Fusion Drive. The fast ion slowing-down is what causes the tritium and other fusion ash to exit the machine. You can view a preprint on arXiv.

We will post again once the paper is published and available from Physics of Plasmas.

Living Universe Documentary

Back in early September, PSS and PPPL were visited by a film crew from Australia. The project? Living Universe: An Interstellar Voyage, which will include a feature documentary, a 4 episode TV miniseries, and a podcast. The documentary touches all aspects of an interstellar mission, from exoplanets to astrobiology, including transportation – which is where our fusion engine work comes in. The film is in production now and the producers expect to launch in late 2018.

The PFRC experiment at PPPL is the only hardware the documentary team could find with a path to fusion propulsion! Dr. Cohen was able to run the machine for the film crew, and both Mike and Stephanie were interviewed extensively. We discussed the rocket equation and the fundamental speed of fusion products, and how DFD moderates that speed with additional propellant to produce higher thrust. For an interstellar voyage, DFD would have to be much, much lighter than we know how to make it today – but who knows what innovations in magnets are possible in the future!

How will you be able to watch the film and TV series? The film should do the rounds of museums and IMAX theaters. The TV series will be available for streaming from Curiosity Stream, a service which specializes in science, history, tech & nature documentaries. We will post an update when we have a firm release date!