Fluxgate Magnetometer Core Technology Demonstrator
A NASA Cubesat Launch Initiative Proposal from the Columbus Space Program
Contact Information:
Columbus High School
PI: Luther Richardson
1700 Cherokee Avenue
Columbus, GA 31906
(706) 888-3124
astro@mit.edu
Fluxgate Magnetometer Core Technology Demonstrator
Proposed by the Columbus Space Program, a co-curricular science and engineering organization
housed at Columbus High School
CubeSat
Mission
Parametes
Mission
Name
FluxDemon
Sat
Mass
Cube
Size
1.3kg
1u
Desired
Orbit
Altitude
Inclination
CubeSat Project
Details
Focus Area(s)
(e.g. science,
technology,educa
tion)
Technology,
Education
Student
Involvem
ent Yes
or No
Yes
Acceptable
Orbit
Range
NAS
A
Fundi
ng
Yes or
No
No
600
km
50
deg
550km –
650km
400 km @
51.6 degree
incl.
Acceptable
– Yes or
No
No
Sponsoring
Organizatio
n(s)
Organizat
ion
Columbus
Space
Program,
AMSAT
Readiness
Date
Desired
Mission
Life
July
2017
5 years
Collaborati
ng
Organizatio
n(s)
List
Prime
Photonics
Internatio
nal – Yes
or No
No
Points of Contact
Mission PI (Overall Systems Engineering, Science & Education Plan)
Organization Columbus Space Program / Columbus High School / AstroSystems, LLC
Name
Luther Richardson
Title
Program Manager of CSP / Science Teacher / Chief Scientist
Address
1700 Cherokee Ave, Columbus GA 31906
Phone
706-888-3124
Fax
706-748-2546
Email
astro@mit.edu
Engineering POC
Organization AMSAT
Name
Jerry Buxton
Title
Address
Phone
Fax
Email
Payload Technical POC
Organization Spatial Microsystems
Name
Keith Warren
Title
Chief Engineer
Address
Phone
Fax
Email
Organization
Name
Title
Address
Phone
Fax
Email
John Klingelhoeffer
Proposal Abstract:
FluxDemonSat proposes to advance the TRL level for NASA research class magnetometers with
a new type of core material. Besides being a technology demonstration mission, this satellite
will also have an education plan that uses an existing network of schools and teachers sponsored
by NASA.
Proposal Detail:
The proposed FluxDemonSat mission has a technology and education prime focus area and a
secondary focus area in science. The focus areas are outlined below in the mission objectives
table with alignment with NASA Strategic Goals (FY2014) in orange text.
Primary Focus
Area Objectives
M1 (Technology)
Advancing the TRL level for the new type of core for fluxgate
magnetometers will increase availability of research class
magnetometers. (NASA SBIR Proposal #11-2 S1.06-8828 copy in
Appendix)
Objective 1.7: Transform NASA missions and advance the Nation’s
capabilities by maturing crosscutting and innovative space technologies.
Objective 2.3: Optimize Agency technology investments, foster open
innovation, and facilitate technology infusion, ensuring the greatest
national benefit.
GSFC Strategic Goal 1: Goddard Space Flight Center both enables and
conducts science research from space.
M2 (Education)
Implement a wide spread education plan that will facilitate a network of
data stations and opportunities for students to analyze data
Objective 2.4: Advance the Nation’s STEM education and workforce
pipeline by working collaboratively with other agencies to engage
students, teachers, and faculty in NASA’s missions and unique assets.
Objective 3.1: Attract and advance a highly skilled, competent, and
diverse workforce, cultivate an innovative work environment, and
provide the facilities, tools, and services needed to conduct NASA’s
missions.
Secondary Focus
Area Objectives
M3 (Science)
Contribute to investigation of the Earth’s magnetic field and its
response to solar activity
Objective 1.4: Understand the Sun and its interactions with Earth and
the solar system, including space weather.
Objective 2.2: Advance knowledge of Earth as a system to meet the
challenges of environmental change, and to improve life on our planet.
Each objective will be addressed in the next section using its M-designation from the focus area
table.
M1.
NASA has been using fluxgate magnetometers to measure magnetic field throughout the history
of space exploration. The best magnetometers for space research have been coming from the
Goddard Space Flight Center (GSFC) with support for missions like the Voyager spacecraft,
Mars Global Surveyor, and current missions like Messanger. These flagship missions have
relied on the low noise high precision fluxgate magnetometers from the Mag Lab at GSFC. In
recent years, there has been a shortage of the permalloy metal cores used at the heart of these
fluxgate magnetometers due to diminishing supplies and a loss of the exact fabrication
process. A Small Business Innovation Research grant was awarded to a company called Prime
Photonics to manufacture a replacement core material using a newly developed metallic glass
core. These cores are intended to serve as drop-in replacements for current NASA designs for
fluxgate magnetometers. This CubeSat mission would fly a fluxgate magnetometer in the form
factor of a small NASA design using a metallic glass core. The data would include magnetic
field measurements that would be compared to a solid state magnetometer for verification, and
also diagnostic data to confirm the performance of the metallic glass cores. The end result would
be performance data on the metallic glass cores operating in a fluxgate magnetometer operating
in a space environment advancing this new technology to a TRL-6 or TRL-7 depending on the
results. TRL 7 is defined as: “A high fidelity engineering unit that adequately addresses all
critical scaling issues is built and operated in a relevant environment to demonstrate performance
in the actual operational environment and platform (ground, airborne or space). ” [NASA, 2007]
Fluxgate Magnetometer Core (Idealized Diagram
from Acuna, 1978)
Small NASA Fluxgate Magnetometer
(image taken by proposal PI at NASA
Goddard Mag Lab in 2004)
Magnetic core performance can be measured as shown in the formula below. The slope
of the hysteresis response of the core is equal to the permeability 𝜇𝑟 of the core, which will be
measured through circuity. A physical manifestation of the core performance can be observed in
Figure 1. The alignment of the magnetic domains of the core determine another measure of core
performance, the demagnetization factor, 𝐷 . Measuring the magnetic field inside the core itself
will give a direct measurement of the alignment of the magnetic domains inside the core and,
thus, a way to determine the demagnetization 𝐷 of the core.
𝑉𝑒𝑥𝑡
𝑑𝜇
𝑑𝑡
= 𝑛𝑠 𝐴𝐵𝑒𝑥 (1 − 𝐷)
1 + 𝐷(𝜇𝑟 − 1)2
Variable of FGM Core Testing
𝜇𝑟 , permeability
𝑑𝜇
𝑑𝑡
, time response of core
𝐵𝑒𝑥 , magnetic field
𝐷, demagnetization of core
Measurement Method
Slope of hysteresis curve as measured by
sense resistor in series with coil
First derivative of data points from sense
resistor
Magnetic field output from FGM
Hall Effect Sensor placed in slot in core
Figure 1: The hysteresis curve of a magnetic material driven to saturation.
Source: http://hyperphysics.phy-astr.gsu.edu/hbase/solids/imgsol/hyloop.gif
For the purpose of measuring the performance of the Prime Photonics core, a flux gate
magnetometer will be used, as outlined in the block diagram in Figure 2. Fluxgate
magnetometers work by saturating the core material with magnetic field and using sense coils to
react to changes in magnetic flux and circuitry can act to nullify the external field (closed loop
sensor) Cubesat FGM will measure Earth’s field to be compared to a solid state magnetoresistive
magnetometer reading – this comparison validates overall measurement ability.
The core itself is wrapped with magnet wire to create a torroidal electromagnet, and this
torroid is placed at the center of a sense coil. The core is magnetically saturated in the positive
and negative directions as driven by an excitation circuit. Since the coil is saturated, any external
magnetic field cannot fit in the torroid’s magnetic field, so it leaks to the sense coil surrounding
the torroid. The change in magnetic field in the sense coil will induce a voltage in the wire,
which is demodulated by circuitry. The sense coil’s output will be tied to circuitry that uses
operational amplifiers to detect the amount of magnetic field through phase demodulation, which
both nullifies the external magnetic field, which makes a closed-loop sensor, and drives a signal
to an analog-to-digital converter (ADC) that sends the high resolution (18-bit or 22-bit)
measurement of magnetic field to the microprocessor, which then logs the data.
Phase demodulation helps the sensor’s noise rejection because only signals that are
exactly in phase with the torroidal excitation will be measured. Furthermore, sine wave phase
demodulation prevents picking up noise or interference from odd harmonics that match the
torroidal excitation phase. To further avoid interference of noisy digital signals in our closed
loop analog circuitry, the signal measurement circuitry, consisting of an ADC and
microprocessor, and other circuitry will be magnetically shielded from the flux gate
magnetometer and its circuitry.
Though monitoring magnetic field measurement itself can measure core performance
over time, a faster, more reliable form of measuring the core responsivity is measured as follows.
To monitor the hysteresis response of the core, a small value resistor is placed in series with the
torroid to measure the excitation response of the core, and the voltage across the resistor, which
directly corresponds to 𝜇𝑟 , can be monitored by the ADC. Another method to measure the coil
performance is to detect the magnetic field inside the core itself, by using a thin Hall-effect
sensor placed inside the core itself. Slots a few millionths of an inch thick can be cut with a
diamond saw and a Hall effect sensor with an analog output, which directly corresponds to 𝐷 ,
can be placed and connected to the ADC.
Figure 2: Block diagram of the flux gate-magnetometer and its circuitry.
Source: Columbus Space Program
It takes a considerable engineering effort to make a spacecraft magnetically clean. This mission
will take basic steps to minimize stray magnetic fields, but the focus is to obtain performance
data on the coil inside of the fluxgate magnetometer. Stray magnetic field from electrical
currents in the satellite will be filtered out using the dual technique by comparing simultaneous
measurements by an industry standard solid state magnetometer in the payload section of the
CubeSat.
M2. Education
The Columbus Space Program is a co-curricular science and technology organization
based at Columbus High School. Student participants in this program have been selected to fly
experiments on NASA suborbital rockets, balloons, space shuttles, ISS, and at drop towers. This
group of students also has worked to develop a high altitude balloon program that has flown 23
missions to the edge of space, regularly exceeding altitudes of 100,000 feet, and participated in
FIRST robotics, an annual high school competition through which students build, design, and
test a 120-pound robot. Ten percent of the population of undergraduate students at MIT have
participated in FIRST Robotics, so this same group of high school students will become the next
generation of scientists and engineers of the caliber suitable for the challenges of NASA
missions. High school students in the Columbus Space Program are poised to advance their
competancy as consummate reseachers and members of an innovative taskforce.
Participation in these activities have enabled access to an extensive international network
of FIRST teams, a national Lemelson-MIT Inventeams, and teachers from various space
program such as Network of Educator Astronaut Teachers (NEAT) and Teachers in Space
(TIS This proposed CubeSat mission is an ideal central concept for an international outreach
program. The goals of this aforesaid program would be to first involve student groups from
around the country as part of the communication network supporting data transmission to and
from the FluxDemonSat, and promote interest in science, technology, engineering and math
(STEM).
Prepackaged lesson plans will be dsitributed to participating schools. These plans will
enable teacher supervisors to involve students in this global network, by tying
Objective 2.4: Advance the Nation’s STEM education and workforce pipeline by
working collaboratively with other agencies to engage students, teachers, and faculty in NASA’s
missions and unique assets.
Objective 3.1: Attract and advance a highly skilled, competent, and diverse workforce, cultivate
an innovative work environment, and provide the facilities, tools, and services needed to conduct
NASA’s mission
M3
The scientific objective of FluxDemonSat is to further NASA Strategic Objective, that is, “to
understand the Sun and its interactions with the Earth and the solar system, including space
weather.” This CubeSat aims to fulfill this objective through accurate measurement of the
strength of Earth’s magnetic field for given location and time. Since solar activity, especially in
the form of ionic radiation, disturbs the electric currents surrounding the Earth, thus causing
disturbances in the geomagnetic sphere, accurate magnetic field measurements from the
FluxDemonSat, especially as observed in LEO, will reveal trends in solar activity. The Cubesat’s
magnetometer will compare data to ground-based magnetometer measurements in order to
subtract the effect of Earth itself on those magnetic readings.
Several spacecraft missions including Cubesats have aimed to investigate the interaction between
the Sun and Earth by measuring the magnetic field from orbit. FluxDemonSat would take data
with as good or better sensitivity than the other missions. This satellite would offer another data
point in time and space.
According to the CINEMA and FIREBIRD CubeSats of UCBerkeley and Boston University,
magnetic field measurements indicating perturbances in the geomagnetic sphere correlate to
electron microbursts from the sun. CINEMA’s magnetometer required a resolution of between
2nT and 10 nT, which is easily achievable by our Sat, as we aim for sub-nT resolution, which is
required for our measurement of the Prime Photonics core performance.
The following graph demonstrates the correlation between magnetic storms and sunspot activity,
as demonstrated by the British Geologic Survey.
Figure: This diagram displays the interaction of solar wind with Earth’s magnetic field. The bow
shock represents the creation of the edge between the magnetopause and the space medium due
to the abrupt drop of the solar wind content as it slowly begins to propogate towards the Earth.
Source: http://www-ssc.igpp.ucla.edu/personnel/russell/papers/magsphere/
UC Berkley CINEMA mission to measure Earth-Sun
interaction
Graphic showing source of magnetic
source measurements from space by
ESA’s Swarm mission
Merit Review
Feasibility Review
Need for Collaboration → Prime Photonics, AMSAT
CharBroil manufacturing capability: parts made from student designs using laser cutting sheet
metal machine, Wire EDM, lathe & milling machines
Prime Photonics supplying low noise metallic glass core designed for NASA FGM sensors
Auburn university’s clean room for final production of electrical circuits and integration
Columbus Space Program Robotics Lab (access to 3d printer)
AMSAT FOX satellite program (subsystem support)
Need to put the Prime Photonics NASA sized drop-in cores inside of a quality fluxgate
magnetometer and measure performance while in orbit.
OPTIONS: Build our own fluxgate magnetometer or Obtain a small NASA magnetometer from
Goddard Space Flight Center Mag Lab
Electronics. Designed, Built, & Tested by Columbus students with guidance by electrical
engineer Keith Warren
Prime Photonics has a Small Business Innovation Research grant with NASA to produce quality
low noise fluxgate magnetometer (FGM) cores that can act as drop in replacements for current
NASA FGM sensors
Contact made with company CEO, Steve Poland. Agreement made that a flight on a Cubesat
with relevant performance data would advance the TRL level of the cores. Agreement made that
low noise cores with O.D. of 1.0 inches would be available within a year to us to be integrated
into a FGM sensor for Cubesat flight.
AMSAT has launched multiple small satellite including Cubesats that have served the amatuer
radio community with education programs
Columbus Space Program would fully manage the payload section of the FluxDemonSat mission
Students from Columbus Space Program would work with AMSAT engineers/mentors to modify
and utilize previously designed subsystems (COM, EPS, CDH, STR)
Skeleton Structure with deployed FGM using a spring-loaded or motor deployed Copper
Beryllium “tape measure”






23 high altitude balloon launches has built student knowledge:
 Communication Systems
 Electronics and Programming
 Integrated Process Teams
DREAMS payloads will serve to test the performance of CubeSat payload prototypes at
altitudes over 100,000 km
DREAMS-24 is scheduled for Nov. 15: 16-bit magnetometer will fly and gather data
Three or more DREAMS launches in the future dedicated to FluxDemonSat testing
Subsystem Costs managed by AMSAT
Payload Costs
 Magnetometer Cores $3000
 3 axis Fluxgate Magnetometer (1 flight, 1 engineering, several 1-axis
versions) $1000

FGM drive circuit (several development versions + 1 flight + 1 engineering)
$2000
 Three Balloon launches (DREAMS) for testing $2500
TOTAL BUDGET (Payload) $8500
Support: Georgia Space Grant $5000, US Army $1500 (Pursuing options for $2000 additional
support – must be documented as letters of support in the proposal)
Costs are for materials and supplies. All labor and site costs are volunteered or donated.
Does the Proposal demonstrate that the CubeSat investigation provides benefits to NASA by
addressing one or more of the goals and objectives of the NASA Strategic Plan?
• Are these the benefits that were reviewed in the merit review?
• Why is an orbital flight opportunity necessary or advantageous for providing these benefits to
NASA?
Review Process
The review process included a succinct set of review questions evaluated by a very experienced review
committee. The same committee was used for both Merit and Feasibility although some participants were
better suited for one or the other. The committee was encouraged to respond by Google form after
receiving the slide deck and also encouraged to participate in a live session using the Cisco WebEx
meeting software. Comments and questions were collected from the Google documents, live session,
email exchanges, and some individual conversations to drive information to be emphasized in the final
proposal. The final draft was also sent to the committee for possible last minute input and changes.
Merit/Feasibility Review Committee
Name
Position
Affiliation
Perry Ballard
NASA/DoD Payload
USAF
John Klingelhoeffer
Electrical Engineer
AMSAT
Taylor Klotz
Communications
WTVM
Eryn Maynard
Software Engineer
Google
Christian Nelson
Launch Systems Engineer NASA
David Rush
Software Engineer
Wyoming State
Bobby Russell
CEO
Quest for Stars
Dr. Chris Spraggins
Science Teacher
Columbus High
Michael Taylor
Launch Controller
SpaceX
Contact
Merit Review, Oct 31st, 2014
Most of the questions for the Merit Review were taken from the National Science Foundation’s
January 2013 Merit Review criteria which were based on a report by the National Science
Board. The succinct set of questions sent to reviewers included:
Does this mission address NASA Strategic Objectives?
What is the intellectual merit of the proposed activity?
What are the broader impacts of the proposed activity?
Is student training used in this activity?
Summary of responses
Comment/Question
Response (actions/answers)
Feasibility Review, November 7th, 2014
The Feasibility Review followed the Merit Review so that responses could be generated and
included. Questions for the reviewers were generated from the NASA CubeSat Initiative
program and from the NSF question set for their Merit Reviews that applied more to
feasibility. Those questions are listed below.
Are the primary objectives technically feasible?
Does the team have the resources to achieve the objectives?
Is the management plan capable of achieving the mission goals with students involved?
Will the team be able to meet its schedule?
What was the feasibility review process?
Summary of responses
Comment/Question
Response (actions/answers)
Risks & Mitigation
<include risk mitigation chart>
Management and Team Organization
Project Management
The “V-diagram” from systems engineering illustrates the engineering approach to
FluxDemonSat. Students will gain a full engineering life cycle experience.
This proposal will present a general feasibility, set of requirements, and some elements of highlevel design.
Verification and Validation (V&V) will be accomplished using a set of design budgets:
Power Budget, Link Budget, Mass Budget, Cost Budget, and Schedule
Schedule
• What were the qualifications of the feasibility review committee members (if possible identify
by name, title, and expertise)?
• What factors did the feasibility review use to assess feasibility?
• How were the management team roles, experience, expertise, and the
organizational structure of the team assessed?
• How was the technical development risk associated with the overall CubeSat mission assessed?
• If the CubeSat investigation requires critical technology development for flight readiness, how
were the areas assessed, and how were the plans for completing technology development
assessed?
• Concerning the development of the CubeSat for flight, how was the probability of success
assessed?
• What was the outcome of the feasibility review?
• How did Respondent respond to and/or address the findings of the feasibility review?
• Is there sufficient financial support for the development of the CubeSat payload and for all
other costs incurred by Respondent to support its participation in the project?
CubeSat primary and, if appropriate, secondary focus area: scientific research question,
technology development/demonstration, or education.
• CubeSat Development: schedule for remaining CubeSat development that supports a launch in
2015-2018.
• Summary of Requirement compliance or required potential waivers.
Funding Commitment Letter(s): letter(s) demonstrating sufficient financial support for remaining
CubeSat development.
• Note for Proposals identified with an Education Focus Area: If the proposed CubeSat includes
outreach components, the proposal must include a description of the education plan.
Compliance checklist and required documents
o Proposal includes demonstration of the benefits to NASA based upon the 2014 NASA Strategic
Plan
o Proposal identifies a project focus area
o Proposal includes a description of the merit review process and outcome including review
committee membership
o Proposal includes a description of the feasibility review process and outcome including review
committee membership
o Proposal fully complies with the Launch Services requirements and identifies any potential
waivers
o Proposal includes a completed Mission Parameters Table
o Proposal includes a completed Project Details Table
o Proposal includes a schedule for remaining CubeSat development that supports a launch in
2015-2018.
o Proposal includes funding commitment letter(s) demonstrating sufficient financial support for
remaining CubeSat development
Importance of Fluxgate magnetometers to NASA
New Cores
AMSAT
Schedule
Education Plan
Merit Review
Feasibility Review
Launch Service Requirements
Financial Plan
Resumes
Plans for Remaining development
Technical Risks & Mitigations
By using a Honeywell magnetoresistive magnetometer (HMC2003), an open-loop triaxial
sensor that detects magnetism by registering magnetically-induced changes in resistance of a
sensitive material, we conducted testing of the natural daily periodic variation in magnetic field
on the ground. The sensor itself has a resolution of approximately 4 nT, while the USGS and
other agencies have observed the periodic variation to be approximately 36 nT.
The data collected so far via ground testing includes a full day and night, registered by a
single HMC2003. A sharp increase in magnetic field takes place around sunset, equally offset by
a sharp decrease, most probably owing to the bow shock of the magnetosphere, around daybreak.
The precise circumstance of these drastic increases and decreases , which occur over the duration
of less than 30 minutes, was not initially certain. To rectify this issue, times for visible magnetic
events were derived from a calibration that encompasses magnetometer exposure to a magnet
(insert magnet type`/strength here) at a known time.
The exposure and subsequent sensor saturation occurred at 4:25:42 PM, and the
magnetometer was switched off at 12:08:00.AM the next day. There are 67752 data points in
between the point of saturation and the switching off, which indicates a sample rate of
approximately once per second.
Sunset occurred 3618 seconds after saturation at 5:41, and sunrise the next day at 7:08,
meaning that roughly 46140 seconds elapsed between sunrise and sunset. The beginning of the
increase in magnetic field readings occurs around 33 minutes after sunset, increasing for 17
minutes until reaching a 20107 counts, the highest reading of the measurement period. There
appears to be a lag time between sunset and the increase in magnetic field, and a lead time
between the decrease in magnetic field and sunrise.