Sun Devil Satellite Laboratory Pulsed Plasma Thruster ...
Transcript of Sun Devil Satellite Laboratory Pulsed Plasma Thruster ...
Sun Devil Satellite Laboratory
Pulsed Plasma Thruster & Space‐Rated Vacuum Chamber Project 2016‐17 Report
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Pulsed Plasma Thruster Project
Above: An artist's rendering of a pulsed plasma thruster (PPT) in operation on a cubesat.
Faculty Mentor: Dr. Daniel White, School for Engineering for Matter, Transport & Energy Project Lead: Aditya Khuller Team Members: Adam Wong, Aronne Travaglia, Edward Vinciguerra, Gargi Kailkhura, Jairaj Mehta, Jenna Moore, Joseph Mayer, Michael Zhang, Ramit Gupta, Raymond Barakat, Tyler Lanes
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Project Summary
Pulsed Plasma Thrusters (PPTs) are highspecificimpulse, lowpower electric thrusters. Pulsed plasma
thrusters are ideal for applications in small spacecraft for attitude control, precision spacecraft
control, and lowthrust maneuvers. Ablative PPTs using solid propellants provide mission benefits
through system simplicity and high specific impulse. These systems exploit the natural properties of
plasma to produce thrust and high velocities with very low fuel consumption. Current PPT systems
utilize a fairly low pulseenergy density. This project aims to increase the efficiency of conventional
PPTs, by developing and designing innovative power processing systems in a costefficient manner. An
igniterless unit will preclude the most common failure mechanism, which is a lifelimiting component
in most thrusters.
Additionally, the PPT project under consideration will operate at relatively high vacuum pressure
compared to GEO altitude, although a spacerated vacuum chamber system is simultaneously
designed and assembled for use of this project and to serve as an asset for the Sun Devil Satellite Lab
for future testing and data collection. This feature (the PPT can operate at relatively high vacuum
pressure) will serve to expand the operational envelope of the PPT for very LEO applications,
especially useful for small spacecraft platforms with typically low ballistic coefficients.
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Introduction
Within the electric propulsion community, there is an increasing interest in the development of small
electric thrusters to provide primary propulsion and attitude control, especially in a configuration that
is suitable for integration in the cubesat platforms. This project is aimed at using a relatively high
pulseenergy density to ablate the solid Teflon fuel directly, without the use of an igniter, to increase
the lifetime of the thruster system exponentially. Unconventional power processing systems
(nonstandard circuit designs and techniques) will also be developed to increase efficiency, reduce
thermoelectrical powerlosses and increase mobility capabilities for the small spacecraft platform,
thereby allowing for more dynamic missions, where the PPT can serve to be used as a primary
propulsion system for interplanetary travel as well as attitude control for Earthorbiting missions.
The project will also serve to utilize existing assets and run concurrently with research being done by
and within the Sun Devil Satellite Laboratory, including an existing vacuum chamber and further
develop benchtop test equipment, like an Attitude Determination and Control System Test Bed.
This project is aligned with ASU’s Ira A. Fulton Schools of Engineering’s research theme of energy, by
innovating new electrical and electronic power processing systems aimed at increased efficiency and
lower thermoelectric power losses.
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Deliverables/Objectives
The specific objectives of this project are:
● · Power Processing Unit Design Characterization
A complete, innovative and costefficient circuit design that incorporates a type of flyback
transformer and switching system to ensure low power losses and high energy output.
● · Demonstration of Burnon (Live and AudioVideo Recording)
A recorded and live demonstration of the thruster will be held, to observe charge, discharge and burn
to characterize efficiency, thrust and power statistics.
● · Mechanical Designs for Thruster Head, Testbed and Performance Measurement
Tools
Engineering drawings and mechanical designs for the thruster (including all its components), the
testbed and necessary performance measurement tools and equipment.
● · Asset for Future Testing/Flight
The PPT design, along with all of its components, can be modified, and altered for different sizes and
scientific applications in the future, to help foster further innovation in producing higher efficiency
designs. The Sun Devil Satellite Lab has a provisional agreement with Orbital ATK, in Chandler, Arizona
for possible cubesat launches in the near future. This work can be utilized for attitude control for such
platforms.
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Project Timeline
● May 20th, Under the supervision of our project mentor, Dr. White, club members worked on
characterizing a Power Processing Unit design for the thruster, consisting of a transformer,
rectifying circuit, voltage multiplier and a switching device to charge and discharge the main
capacitor bank.
● June 10th, club members will design CAD models of the inlet flange interface for the Diffstak
Diffusion pump into the vacuum chamber as well as a thruster headswitchvacuum chamber
interface to connect the PPT to the chamber.
● June 15th, club members will connect the Edwards Diffstak 63/150M diffusion pump and the
Edwards RV5 roughing pump to the vacuum chamber that we built using a series of valves and
test and record vacuum values using the DVG64 digital vacuum gauge.
● July 15th, club members will construct a functioning PPT prototype.
● August 20th , club members will begin data analysis of characteristic current waveforms to
measure thrust and efficiency.
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Project Expenses
Expense #1 (Expense Title) Line Item # Line Item Name Expensed
1 Digital Pressure Gauge $193
2 KF25 Vacuum Hose $159.9
3 KF25 4Way Cross $121.8
4 KF25 Clamp $38.75
5 KF25 Flange ORing $34.75
6 VacuumIsolation Angle Valves $340.57
7 Vacuum Oil $22.00
8 Copper Rods $10
9 Copper Tubes $30
10 PTFE (Teflon) Rods $10
11 Edwards RV5 Roughing/Backing Pump $736.485
12 Edwards Diffstak 63/150P Diffusion Pump $861.485
13 PPU Parts (Capacitors, Circuit Boards, Resistors, Wiring, IGBT Switch) $200
Total Cost $2758.74
Raytheon Funding Log201516 (last year) Expense Item Expense Item Name Awarded Expensed
1 Raytheon Funding $3000 $2758.74
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Project Description
The funds from Raytheon utilized for the PulsedPlasma Thruster project this semester acquired
all components necessary for the vacuum pumping system, its connections/adapters, a digital
pressure gauge, the thruster head materials, and the PowerProcessing Unit electronics. With
all these parts purchased, a PPT prototype will be able to be designed, created, and tested.
The vacuum system consisting of all valves, pumps, etc. will be able to simulate lowearth orbit
conditions desired to test a PPT. We needed to purchase an Edwards RV5 backing pump (used)
with an Edwards Diffstak 63/150m diffusion pump (used) . This was an unforeseen event
(switching pumps) because we needed a backing and diffusion pump that were compatible with
each other, which we did not have originally. The reason this occurred was because the
members working on the project previously were unaware of the two pumps incompatibility.
After much research and analysis, we decided on the two previously mentioned pumps due to
their lowcost, compatibility, and our access to the manufacturer. The digital pressure gauge
will be connected and our overall pressure will be determined.
Below (from left to right): Edwards Diffstak 63/150m, Edwards RV5, SDSLbuilt vacuum chamber
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Figure – Block/Stage Diagram of Benchtop Power Processing Unit (PPU) for the SDSL Pulsed
Plasma Thruster
The PPU could be considered to be one of the most important aspects of the PPT project
because without it, we would have no power, no discharge and therefore no thrust. A voltage
converter circuit has been designed using low cost components and is in the process of being
simulated, analyzed, and then built. The process of designing the correct circuit with the right
characteristics has taken a while but after much consideration a schematic for the circuit
diagram was created under the direction of our mentor Dr. White, an expert in electric
propulsion.
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Above: An engineering drawing of the PPT Thruster head.
The thruster head materials purchased include the copper rods, tubing and teflon (PTFE) tubing.
We will have three uniquely dimensioned thruster heads each with more than two physical
models by developing CAD models that will be machined and integrated within the system. This
should provide us with enough room to test under varying and controlled conditions.
Impact of Project Funding
The Raytheon funding SDSL received this year has had a large impact on the club this year and
for the years to come. It has allowed us to engage the students within the club as well as
members of the public (through outreach events like Fulton’s DiscoverE Day and SESE’s Night of
the Open Door) in a number of different ways this year.
This project in particular has helped garner a lot of interest amongst old and new club
members, and has significantly boosted club member recruitment. We were able to do this by
giving the students a number of projects that they could jump into and get some real world
experience not found in the classroom. Skills including setting up and performing space and
engineering experiments, learning to work together on teams and subsystem teams, using
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engineering methods to design and build prototypes (by using CAD software as well as machine
shop tools) and go beyond what is taught in class by learning about vacuum systems, their
operation as well as electromagnetic processes to increase thrust and efficiency. These skills are
paramount to learn how to be an engineer in the real world, with real problems and real risks,
with budgetary and engineering constraints to achieve a tangible goal.
The Raytheon funding has also allowed us to develop two different types of test beds that will
allow the club to perform test on new technologies for years to come. This will provide SDSL
with the chance to be more independent. We will no longer have to pay other organizations
large fees to use their equipment and work around their schedule in order to get access to a
vacuum chamber so that we may test our new spacecraft propulsion system.
By developing our own inhouse vacuum chamber and testing facilities, SDSL can then allow At
a smaller organizations (like other clubs, and even nearby high schools) a chance to get their
hands onto our testing equipment for their projects under our supervision.
Evaluation Methods/Quantifiable Data Plan
Our Pulsed Plasma Thruster and spacerated Vacuum Chamber system will be ready for use by
endAugust 2016. Using quantifiable methods of data analysis by using current waveforms, we
expect to be able to make alterations to our PPT design to eventually miniaturize it to the point
where it can be incorporated onto cubesat platforms on future SDSL missions.
Future Planning/Outreach
The Sun Devil Satellite Laboratory has put itself into a great position to expand its horizons in the next few years. On April 6, 2016, NASA announced that SDSL’s Phoenix mission had been chosen to be fully funded and launched by NASA. The Sun Devil Satellite Laboratory is currently leading a highly qualified team of undergraduate students (including those working on the Pulsed Plasma Thruster project) at Arizona State University, for the Phoenix mission, working under highly experienced faculty like Dr. Judd Bowman (PI) and Dr. Philip Christensen, a NASA veteran scientist and ASU Regents Professor. In short, the mission consists of utilizing an infrared cameraequipped 3U cubesat to measure the effects of the heat island phenomenon in different cities across the world.
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Below (left to right): SDSL’s NASAfunded Phoenix mission incorporates many aspects of science and engineering for undergraduate students to learn from; SDSL’s AIAA Cansat competition also encompasses building, designing, flying and successfully recovering an integrated circuit module while recording flight data.
Similarly, The AIAA annual CanSat competition has given us a great base to build on. It has provided us with a yearly, multidisciplinary project that involves building, designing, flying and successfully recovering an integrated circuit module while recording flight data. Networking within Arizona State University, industry, and government entities is the key to the future of SDSL. To help us network within these areas we have developed an impressive support system within the school. With the help of three professors on campus we are working on communicating with JPL, NASA, and industry leaders through the ASU NewSpace initiative. We hope from this communication we can get a better understanding of what these organizations are looking for in a student organization and what we can do to better appeal to them. By better understanding what we can all do for each other we believe that SDSL will be able to develop a working relationship with all of these organizations. By partnering with industrial leaders like Raytheon, we hope to be able to test our cubesat propulsion systems in orbit one day. We are also working on implementing a k12 program with nearby high schools to integrate their electromagnetic waves lessons (usually in PhysicsII class), with an ‘Application Of’ lesson about electric propulsion to inspire them into becoming engineers by seeing realworld applications of the science that they learn about is an important step in generating future engineers and scientist. We believe that by educating and sparking an interest in the younger generations we can ensure a bright future for space exploration and spacecraft technology. We are also considering using the popular rocketry game “Kerbal Space Program” in order to help students grasp the concepts behind launch vehicles and orbital dynamics. Our outreach team has also put together a gravitywell to demonstrate to students and members of the public the effects of gravity, in a way that they can see and perceive: with marbles and weights as planets and moons!
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Below: A demonstration of SDSL’s gravity well at ASU Homecoming 2015.
We have also thought of creating a pamphlet/ brochure/ informative guide to electric
propulsion that we can distribute at outreach events. We have also developed ties with The
Society of Physics Students at ASU, who frequently do demonstrations of Lorentzforce
applications so that we can expound on their demos to show students actual engineering
applications of electromagnetic waves in space propulsion.
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