The New Space Age Conference

Charles Swanson of PPPL and Mike Paluszek of Princeton Satellite Systems attended the MIT New Space Age Conference at MIT on March 11. It was held on the 7th floor of building E52 at MIT.

Building

Princeton Satellite Systems was a sponsor of the event. It was a great event! There were a number of interesting presentations including one on the history of the Iridium Program. Iridium was almost ready to deorbit the constellation when an investor cobbled together enough money to keep it flying and then found a new market in places without any cell phone service. They are now  launching Iridium-Next. After the disappearance of the Malaysian Flight 370, the airlines realized that they need to know the position of all planes in real-time. Iridium offered a hosted payload to do that and that payload is effectively funding the new satellites. The speaker showed us a image from their satellite showing the tracks of aircraft.

Professor Loeb gave an overview of the Starshot project to accelerate small sails to 20% of the speed of light. He discussed some of the challenges of the program. The speed was selected specifically so that the probes would reach Alpha-Centauri during the lifespan of the investigators.

Boeing gave a talk on composite structures. The speaker, Dr. Naveed Hussain, VP of Aeromechanics Technology, The Boeing Company, showed how established companies are innovating.

Spaceflight gave a talk on their launch services. We plan to work with them to launch our test satellites.

At lunch Charles and I sat with a group of students from Mechanical and Aerospace Engineering Department at Princeton University. We were joined by Mark Jernigan, Associate Director, NASA/JSC Human Health and Performance Directorate. We talked with him about the challenges of human spaceflight to Mars.

Charles and I were on the propulsion panel. Charles gave a spectacular overview of the plasma physics of our nuclear fusion engine. I filled in the DFD system details. We had a few questions from the audience.

Our 2017 extern, Eric Hinterman, gave a great talk on the oxygen from carbon dioxide project that will be tested on Mars. It would produce the oxidizer for return missions thus saving money. My wife, Marilyn, took pictures of the panel.

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At the reception we were the only sponsor with a table display.

Table

It was a great event! We look forward to attending next year!

 

Opening for a part-time bookkeeper/administrator

We are looking for an energetic, results-oriented person able to combine the responsibilities of financial manager and coordinator of back office operations, working part time (16-20 hours/week).

Responsibilities include but are not limited to:

  • financial planning and budgeting;
  • accounting and bookkeeping;
  • customer invoicing and cash management;
  • procurement;
  • HR record keeping and benefits management;
  • coordinating payroll working with an external service provider;
  • managing office facilities.

A candidate must have financial education and a proven record of at least 3 years independently performing on a job with similar responsibilities, possession of skills in QuickBooks or a similar financial package along with MS Office. Excellent communication skills are anticipated.

Please send resumes to info@psatellite.com! Also see our post on LinkedIn.

MATLAB Machine Learning Book is Now Available

Apress just published our new book, “MATLAB Machine Learning”

9781484222492

written by Michael Paluszek and Stephanie Thomas. The book covers a wide variety of topics related to machine learning including neural nets and decision trees. It also includes topics from automatic control including Kalman Filters and adaptive control. The book has many examples including autonomous driving, number identification and adaptive control of aircraft. Here is a view of a neural net tool included with the book.

MultiOutputNet

Full source code is available. For more information go to MATLAB Machine Learning.

Princeton Satellite Systems Awarded Nuclear Fusion Patent in Japan

Princeton Satellite Systems was awarded its first patent in Japan, “Method to produce high specific impulse and moderate thrust from a fusion-powered rocket engine”. This technology was licensed from Princeton University’s Princeton Plasma Physics Laboratory. It is for a compact, low-neutron, nuclear fusion reactor that can be used as a rocket engine or as a power generator. The reactor can be built in sizes from 1 to 10 MW. A typical robotic spacecraft would use two engines. A human mission to Mars or the outer planet might use six 5 MW engines.

Here is the Japanese patent certificate.

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US-Japan Compact Toroid Workshop 2016

Mike Paluszek of Princeton Systems, Sam Cohen of the Princeton Plasma Physics Laboratory and Charles Swanson also of PPPL attended the US – Japan Compact Toroid 2016 meeting in Irvine California this past August.

We presented papers related to Sam’s Princeton Field Reversed Configuration nuclear fusion reactor research program. Charles presented, “Extracting electron energy distributions from PFRC X-ray spectra,” Sam presented “Long pulse operation of the PFRC-2 device” and Mike presented, “Fusion-enabled Pluto orbiter and lander”.

Here are the workshop attendees.

2016us-japanworkshoponcompacttori-groupphotoirvineca

It was fascinating to listen to all of the papers at the workshop! John Santarius, who has done cutting edge work on space propulsion and small fusion reactors presented his talk, “Aspects of Advanced Fuel FRC Fusion Reactors.” He gave a very informative overview of small fusion reactors and advanced fusion fuel technology. Thomas McGuire discussed the Lockheed Martin research on small reactors. There were several presentations by Tri-Alpha Energy scientists on their beam heated FRC.

We look forward to the next Compact Toroid Workshop!

Celebrate Princeton Invention 2016

Michael Paluszek and Gary Pajer of Princeton Satellite Systems attended the Celebrate Princeton Invention (CPI) 2016 reception in the Chancellor Green Rotunda on the university campus.

Our research on small nuclear fusion reactors is part of a team effort with the Princeton Plasma Physics Laboratory (PPPL) so our display was part of the PPPL booth.

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The poster describes our project to design a nuclear fusion propelled robotic spacecraft to go into orbit around Pluto. It would get there in about 3 years and deploy a lander. While in orbit it would return HDTV quality images and massive amounts of data through its high power communications links.  The short duration of the trip would save almost $300M in operations costs. It would be launched from Low Earth Orbit, saving even more money!

The propulsion system could also be used for a Neptune Orbiter, missions to Jupiter’s icy moons, an Enceladus lander, asteroid deflection and human exploration of Mars. More down-to-earth applications include powering bases in Antarctica and driving the propulsion systems for unmanned underwater vehicles.

Our reactor uses helium-3 as a fuel. As the supplies of helium-3 grow, possibly from Canada’s CANDU reactors, helium gas from natural gas extraction or mining the moon, the reactor could be used to generate power everywhere. It is the ideal supplement to wind and solar power.

Gary Pajer and I talked with many attendees at CPI. Here is Gary talking with a visitor to our booth.

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Visitors to our booth included researchers from Schlumberger, ExxonMobil and from around the campus. It was great fun talking to everyone and seeing all the interesting research done at Princeton University!

3-D Modelling of Direct Fusion Drive Rocket Engine

My name is Matthew Daigger and I’m a mechanical and aerospace engineering major at Princeton University going into my senior year. I was given the opportunity to intern and learn at Princeton Satellite Systems this summer. Through this internship, I got a lot of valuable experience in 3-D modelling, research and design. I was able to work with the fantastic engineers at Princeton Satellite Systems as well as Princeton Plasma Physics Lab, who helped whenever questions in their areas of expertise arose.

Side view of the reactor showing the coils

DFD CAD model generation by Matt Daigger

The Direct Fusion Drive (DFD) is an innovative and exciting new technology being designed by Princeton Satellite Systems. This Rocket engine utilizes the Princeton Reverse Field Cycle fusion reactor setup in order to create both thrust and power for a satellite. The vehicle it is currently being designed for is an exploratory satellite being sent to Pluto. What makes the DFD unique is that it can potentially halve the flight time to Pluto, from ten years to five, as well as have enough fuel left to put the satellite into orbit. Along with this, the craft should have enough extra power to deploy a rover to the surface of Pluto and power a drill. This technology could also open other exciting doors, such as manned missions to Mars, given its capability to cut travel times so drastically.

The first task I worked on this summer was looking into how to incorporate a Brayton cooling cycle into the design of the DFD. This Brayton cycle had a dual purpose. The first is to help cool the reactor and prevent too much heat and radiation from escaping and potentially damaging other parts of the satellite. The second function is to re-use this waste heat and convert it back into usable energy. Two simple brayton cycles running in parallel were chosen in order to maximize heat absorption from the reactor and power developed. The working fluid, its flow rate and the diameter of piping, as well as approximate dimensions of the turbine and compressor were also determined. Another important design factor is the ability for the satellite to withstand launch loads. Preliminary launch load calculations were also done in order to get a better idea for the stresses involved with launch using a Delta IV Heavy launch vehicle.

All of this information helped to conceptualize the physical design, which was drawn up in Inventor. The shielding and incorporation of the Brayton cycle flowing through the shielding were ideas which were confirmed by members at PSS and PPPL. The length of the reactor is a key factor in determining how high energy it will be. The length was chosen so to produce a 1 MW engine. The superconducting coils were also a main topic of research. These are active superconductors which are used to shape the plasma. This is still an ongoing process, as using active coils hasn’t been done before, and our engine has unique weight and size limitations which other similar lab reactors don’t. The debate as to whether to use high temperature or low temperature superconducting coils comes down to total size and weight, including that of a cryo-cooling system in the case of the low temperature coils. High temperature superconducting coils are the more massive option, which generally makes them less desirable for space application. The support structure was designed to keep the size compact while being able to handle the stresses calculated earlier. All information about the RMF heating coils, which are used to actually excite and drive the plasma, was received and confirmed by colleagues at Princeton Plasma Physics Lab. The separation coils at the tail-end of the thruster are power variable, and allow the expelled products to be manipulated, giving the engine high precision control in space travel.

Overall, this was an incredibly interesting and educational experience. The work that the Engineers are doing at PSS is innovative and exciting. The big ideas that are being developed here today are what lead to the next big step in space travel tomorrow. I am very thankful for the opportunity to spend my summer here and learn from some of the best engineers in the industry.

Low-jitter Reaction Wheel Prototype for Kestrel Eye

The Army is developing the Kestel Eye imaging microsatellite to provide ground imagery directly to the warfighter.    The goal of the program is to provide tactical grade images to forces on the ground at any time and deliver the images fast enough for use in fast moving ground operations. The satellite will provide battlespace awareness for rapidly evolving tactical situations on the ground, for example: the implanting of Improvised Explosive Devices (IEDs); perimeter security of forward operating locations; or movement of hostile motorized forces.

Princeton Satellite Systems is under contract to develop a control system to  meet the exacting standards of stability, satellite location, and pointing accuracy required to meet the needs of the Kestrel Eye satellite.  The objective of our work at PSS is to improve the pointing accuracy or the ground location accuracy of the Kestrel Eye imagery from 60 meters to 10 meters or less.

The features of the proposed control system that are critical to enabling this superb accuracy are:

• Ultra-precise star image centroiding with custom algorithms
• Miniature precision fiber-optic gyro for attitude base and high bandwidth control
• Low-jitter microsatellite reaction wheels utilizing Halbach array motors
• Nonlinear attitude filters incorporating star camera and nontraditional measurements • Composite structure to eliminate thermal distortion
• GPS orbit determination enhanced with two-way ranging

Recently, PSS has completed the design and fabrication of the first prototype reaction wheel.  The wheel is driven by a low-jitter axial flux brushless DC motor, the design of which is currently under patent review.   An important enabling technology is the Halbach array of magnets.  A Halbach array is sequence of permanent magnet segments, each with its magnetic axis rotated from the axis of its neighbor.  The resulting assembly concentrates almost all of the magnetic field on one side, with an almost negligible field on the other side.  This arrangement favors an axial flux motor with a single stationary stator holding coil windings sandwiched between two permanent magnet rotors, each of which has its Halbach field directed toward the stator.  The sketch shows the arrangement.  The stator is green, and the two rotors are red.

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We’ve gone through a number design iterations,  settled on a first prototype design, and fabricated it.  We also purchased a simple general-purpose motor driver in order to explore the operation of the motor before moving on to developing custom driver electronics.

We’re very pleased that our first iteration works.  Here’s a video showing the device in action.

We’re already at work on the second-generation wheel incorporating lessons learned in the first prototype.

NEA Scout Toolbox

Near-Earth Asteroid Scout, or NEA Scout is a exciting new NASA mission to map an asteroid and achieve several technological firsts, including being the first CubeSat to reach an asteroid and demonstrate CubeSat technologies in deep space. http://www.nasa.gov/content/nea-scout

NEAScoutCAD

NEA Scout will perform a survey of an asteroid using a CubeSat and solar sail propulsion and gather a wide range of scientific data. NEA Scout will be launched on the first Space Launch System (SLS) launch.

NASA asked Princeton Satellite Systems to develop custom MATLAB software based on the Princeton Satellite Systems Spacecraft Control Toolbox and Solar Sail Module to assist with this mission. We just delivered our first software release to NASA!

The NEA Scout module provides MATLAB scripts that simulate the spacecraft. One, TrajectorySimulation, simulates just the trajectory. It includes a solar sail force model and uses the JPL Ephemerides to compute the gravitational forces on the sail. In addition it can use a 150 x 150 Lunar Gravity model during lunar flybys. It also simulates the orbit dynamics of the target asteroid.

AttitudeSimulation expands on this script. It adds attitude, power and thermal dynamics to the model. A full Attitude Control System (ACS) is included. This ACS uses reaction wheels and optionally cold gas thrusters for control. Momentum unloading can be done with the thrusters our using NASA’s Active Mass Translation (AMT) system that moves one part of the CubeSat relative to the other to adjust the center-of-mass so that it aligns with the system center-of-pressure or adds a slight offset to unload momentum. The control system reads command lists that allows the ACS to perform attitude maneuvers, do orbit changes with thrusters and for the user to change parameters during simulations. It adds the rotational dynamics of the asteroid.

The dynamics of the AMT can be modeled either with a lag on the position or a full multi-body model. Dynamics of the reaction wheels, including a friction model, are included in the simulation. The following are a few figures from a typical simulation.

The first figure shows reaction wheel torques during attitude maneuvers. The ACS uses quaternions as its attitude reference. You can mix reaction wheels and thrusters or use either by themselves for attitude control.

RWATorque

This GUI shows the current command and allows you to control the simulation.

CommandGUI

The Figure GUI lists all figures generated by the simulation. It makes it easy to find plots when you have many, as you do in the attitude simulation.

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The Telemetry GUI gives you telemetry from the ACS system. You can easily add more data to the telemetry GUI which can have multiple pages.

Telemetry

This figure shows solar sail pointing during simulations.

SailPlot

The following figure shows the spacecraft with its solar sail deployed. This is built in the CAD script using the  Spacecraft Control Toolbox CAD functions. The sail is 83 meters square.

NEAScoutCADWithSail

The sail is huge but the core spacecraft would sit comfortably on your desk.

If you want more information about our products or our customization services you can email us directly by clicking  Mission Simulation Tools.

NASA Innovative Advanced Concepts (NIAC) Selection

We are very pleased to announce that Ms. Stephanie Thomas of Princeton Satellite Systems has been selected to be a 2016 NIAC Fellow. This Phase I study, entitled “Fusion-Enabled Pluto Orbiter and Lander,” will explore the possibility of using Direct Fusion Drive (DFD) to deliver an orbiter to Pluto complete with a lander. DFD is a fusion propulsion concept built upon a small, clean field-reversed configuration fusion reactor with a naturally linear geometry. The reactor becomes a rocket engine when additional propellant flows through, providing power as well as propulsion in one integrated device. This engine could halve the transit time to Pluto to 5 years from the nearly 10 years needed for New Horizons, while delivering 1000 kg worth of payload into orbit and providing up to 2 MW of power. This will enable remarkable data collection such as high-definition video and drilling into the planet’s surface. The technology provides a path to terrestrial fusion as well as eventual human missions across the entire solar system. The Phase I study will focus on creating higher fidelity models of the engine performance to enable optmization of possible mission trajectories and better quantification of the predicted specific power.

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