Apress just published our new book, “MATLAB Machine Learning”
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.
Full source code is available. For more information go to MATLAB Machine Learning.
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.
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.
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!
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.
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.
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!
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
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.
This GUI shows the current command and allows you to control the simulation.
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.
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.
This figure shows solar sail pointing during simulations.
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.
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.
Princeton Satellite Systems had a booth at the PPPL’s Young Women’s Conference at Princeton University. Stephanie Thomas and Gary Pajer talked with students about our work in aerospace and energy.
Our booth featured a CubeSat frame designed by our mechanical engineers, a simulation of a lunar lander which could be controlled via a joystick, a copy of our new textbook MATLAB Recipes, and a Lego model of our Space Rapid Transit space plane.
The girls were divided into three large groups that rotated through the various attractions available to them, so every hour or so the the attendees changed. And every hour or so we had a fresh cohort of faces to meet. Many of the girls were very interested in what we are doing, and asked insightful questions. For example, one girl asked “What happens when a satellite loses track of where it is? Does it just get lost?” Of course, that’s an important issue, one that we at PSS have spent considerable time addressing.
Some girls were very interested to learn about tiny CubeSats (“This isn’t a model, this is the actual size of the satellite!”), and still others were interested in horizontal launch possibilities as shown by the Lego model – i.e. most rockets launch vertically, but this could take off at any airport. Both of these are examples of systems that we regularly model using our commercial software packages.
For more information see the 2016 Young Womens’ Conference
Mike Paluszek gave a talk on the Pluto Orbiter mission to the Rutgers Engineering Honors Council Keynote Speaker Event on March 22, 2016. The talk covered the mission and spacecraft and outlined the design process. Mike also discussed engineering careers and how to make the most of one’s own career.
From a member of the audience, “Just wanted to thank you once more for the wonderful talk you gave last Tuesday evening!”
This is a photo of the group.
A photo of Mike with the officers.
New functions in the Lunar Cube module in 2016.1 allow you to easily plan lunar insertion and orbit change maneuvers. In the following pictures you can see a lunar orbit insertion from a hyperbolic orbit. In all figures the lunar terrain is exaggerated by a factor of 10.
The same maneuver looking down on the orbit plane. The green arrows are the force vectors.
The following figure shows a two maneuver sequence. The first puts the spacecraft into an elliptical orbit. The second circularizes the orbit.
We are adding the Lunar Cube Module in 2016.1 to our CubeSat Toolbox for MATLAB! It allows users to analyze and simulateCubeSats in lunar transfer and lunar orbit. It includes a new dynamical model for CubeSats that includes:
- Earth, Moon and Sun gravity based on the JPL ephemerides
- Spherical harmonic lunar gravity model
- Reaction wheels
- Power generation from solar panels
- Battery energy storage
- Variable mass due to fuel consumption
- Solar pressure disturbances
- Lunar topographic model
- New graphics functions for lunar orbit operations
- Lunar targeting function
- Lunar mission control function for attitude control and orbit control
The module includes a script with a simulation of a 6U Cubesat leaving Earth orbit and reaching the moon. The following figure shows the Earth to Moon trajectory.
This figure shows the transfer orbit near the moon. The lunar topography is exaggerated by a factor of 10 to make it visible. It is based on Clementine measurements.
Here are results from the new LunarTargeting function. It finds optimal transfers to lunar orbits. The first shows the transfer path to the Moon’s sphere of influence.
The next shows the lunar hyperbolic orbit. In this case the transfer is into a high inclination lunar orbit.
Contact us for more information!
Stofiel Aerospace LLC had a display at the Consumer Electronics Show. They invited Princeton Satellite Systems to display its products on their table. The booth is shown in the following picture. You can see Stofiel’s rockets.
Here is a closeup showing our 3U CubeSat with a camera mounted in one of the bays.
Members of the Stofiel team:
More members of the Stofiel team:
Stofiel Aerospace LLC is an aerospace solutions company created by five U.S. military veterans from Cleveland, Ohio. Stofiel Aerospace LLC is currently developing a portable micro/nano-satellite launch system. Their revolutionary system drastically reduces the wait time for small payloads to reach low Earth orbit to days, not years. By utilizing solid rocket motors and Hydrogen-filled balloons, their system finally offers CubeSat manufacturers and clients the opportunity to be considered a “primary payload” for orbital missions. Currently, they are partnered with the Ohio Aerospace Institute in Cleveland, Ohio and working for further funding to continue development of this industry-changing technology. For inquiries, please contact Jason Beeman, CFO at (440) 994-9035.