IMESA-R
IMESA-R
Integrated Miniaturized Electrostatic Analyzer – Reflight
Dr. Parris Neal
Cadet First Class Alex Strom
Cadet First Class Nikolas Taormina
USAF Academy
Principal Investigator: Geoff McHarg
719 333 2460
[email protected]
13 April 2015
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
1
iMESA-R: A space weather
constellation
 Four inexpensive space weather instruments
 Each instrument provides two measurements
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Low energy plasma (Electrostatic Analyzer)
Radiation (Dosimeter)
 Low size, weight, power (SWAP)
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10x12x4.5 cm
2.1 W without dosimeter, 2.5 W with dosimeter
 DoD Space Test Program (STP) providing
flights on four different spacecraft
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iMESA-R flight instrument for GPIM
Green Propellant Infusion Mission (GPIM)—FY16
Orbital Test Bed (OTB)—FY-16
STPSat-4—FY-17
STPSat-5—TBD
 First DoD space weather constellation
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24 degrees inclination—525-720 km (GPIM and OTB)
51.6 degrees inclination—425 km (STPSat-4)
97 degrees inclination—550 km (STP Sat-5)
13 April 2015
iMESA-R Constellation with four concurrent satellites
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
2
Scientific and Military Problem
 Big Picture: Operators need to quickly
distinguish between environmentally
induced and possible hostile anomalies
 iMESA-R concentrates on ionosphere and
ionizing radiation
 Ionosphere: Plasma irregularities
(“bubbles”) cause scintillation
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Loss of GPS lock
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<50% availability* during severe scintillation
Loss of SATCOM
Knipp, Understanding Space Weather, 2011
 Radiation: Single event upset, dose effects,
deep dielectric charging
 Forecasting is a priority—requires nowcast
 Nowcast requires multipoint measurements
 iMESA-R provides 4 satellite constellation
* For LPV-200. Seo, J, PhD thesis, Stanford Univ, 2010
13 April 2015
Van Allen Radiation belt image created using data from
NASA Van Allen Probes: Note emergence of third
transition belt: Image Credit APL, NASA
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
3
Heritage and Future
 Technology patented by USAFA
 Development funded by AFOSR and AFRL
 IMESA launched on:
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MISSE7(ISS) iMESA 2009-2011 = 1st data collect
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STP-H4 MESA launched Aug 2013 = 1st reflight
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STPSat-3 iMESA launch Nov 2013= 2nd reflight
 Mature hardware, software, electronics
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Demonstrated success on three missions
MISSE7 Credit:NASA
 Future:
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GPIM Launch Mid-2016
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OTB Launch Mid-2016
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STP-Sat 4 Launch Read Aug 2017
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STP-Sat 5 TBD
iMESA STPSat-3 Credit
Ball Aerospace
13 April 2015
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
4
STPSat-3 IMESA-R Data
 Top panel: raw data product:
energy-time spectrogram
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Density increases into
sunlight
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Energy increases into
sunlight
 2nd panel down: Ion
Temperature
 3rd panel down: Ion Density
 Bottom panel: derived
spacecraft charging
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Energy varying over daynight cycle between 25-40
eV
STPSat-3 Data: iMESA data product for one orbit 17 Feb. 2015
 Issues:
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Data drop out over portion of
orbit
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Temperatures not well resolved
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EMI due to power converters
13 April 2015
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
5
Changes for iMESA-R flights 3-6
 New electrostatic analyzer (ESA) design
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Improved temperature measurements
Reduces number of plates—ease of manufacture
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Allows for different host S/C charging
 Programmable gain amplifier
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Assures data collection during entire orbit
Higher transimpedance amplifier gain
ions
 New power supply design
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Collection Anode
 Switchable range on ESA
New ESA Design
Reduces EMI
Change of one power supply allows flights on
many different satellites
 Added dosimeter
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Allows ionizing radiation monitoring
 Rewrote software
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Assures modularity and future upgrades
Single mezzanine bus: -6dB noise reduction
13 April 2015
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
6
iMESA-R Design Philosophy
 Multi-disciplinary
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Physics—ESA design, calibration and analysis
Physics—Dosimeter modelling and calibration
Electrical and Computer Engineering: Electronics design and test
 Use of Commercial Off The Shelf (COTS) components
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Reduced cost
East of integration
Requires space qualification
 “Good enough” versus “gold standard” measurements
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Numbers count in terms of improvement to model output
Small SWAP minimizes host S/C impact and increases
 Evolutionary design changes
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Pick a basic technology
Develop on-orbit flight heritage—learn as you go
Change when needed, not because you can
13 April 2015
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
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How many measurements are
enough?
 Modelled three orbital scenarios (Balthazor et al. 2015, Radio
Science)
 Compared ionospheric model output with and without iMESA on
orbit
 Collaborative effort with Utah State University
 A: 10x satellites @ 500 km
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“String of pearls”
90º inclination
1 launch
 B: 10x satellites @ 350 km
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“String of pearls”
90º inclination
1 launch
Example 25 satellite Walker Constellation
 C: 25/5/1 Walker Constellation @ 500 km
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60º inclination
5 launches
5 satellites per launch
~1-10 year lifetime
13 April 2015
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
8
Scenario A,B (“string of pearls”)
Vertical propagation of information
GPS-TEC only
GPS-TEC
+ Sats @ 500 km
(A)
GPS-TEC
+ Sats @ 350 km
(B)
 Converges towards “truth” with 10 satellites
• Model improvements at all altitudes – not just orbital altitude
• Knowledge “moves along field lines”
• Can quantify “accepted error” and use to fine-tune orbital parameters
13 April 2015
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
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Mean height of F2 peak
improvement quantification
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Various metrics can be used to quantify
improvement by adding IMESAs
Metrics can depend on conditions – position,
time, geomagnetic activity
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25 IMESAs improves RMS to ~10 km
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25 iMESAs improves Skill score to > 75%
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Without IMESA
With IMESA
RMS deviation of hmF2 (global sum)
13 April 2015
Skill score of hmF2 (global sum)
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
iMESA-R Mechanical Overview
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Fits in a 45mm x 102mm x 126mm envelope (without RBF Cover)
Mass is NTE 1kg (including mounting hardware)
Mounting interface is six #6-32 Bolts
Al 6061-T651 per ASTM-B209
Printed circuit boards (PCBs) are enclosed within the assembly
Designed to fit PC-104 boards
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Keying features on boards
Easy integration into CubeSats (for future missions)
 Modular structure design to be barnacle mount or panel flush mount
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Easily accessible Programming ports in either configuration
PC-104 Board Size (with
Keying Features)
13 April 2015
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
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iMESA-R Exploded View
RBF Cover
Enclosure
Plate
Brains Board
Lower Mounting
Enclosure
13 April 2015
Programming Port
Blanking Plate
Connector
Ring
Heads Board
Assembly
Upper
Enclosure
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
12
Hardware Simplified Block Diagram
= Switchable gain
amplification chain
= iMESA-R peripherals
= Data and command
pathways
=Signal paths
13 April 2015
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
13
Software Block Diagram
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Simple heritage code design
Rewritten from scratch for OTB &
GPIM IMESA-Rs
Minor changes anticipated to
accommodate μcontroller change
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Command processing
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Sweep processing
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Spacecraft communication
13 April 2015
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
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iMESA-R Summary
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Unique 4 satellite constellation for space weather
Simplified design allows reduced cost, increased numbers of measurements
Cadets learn about space by doing a real mission end to end
Multi-disciplinary USAFA effort emulates AF space enterprise
USAFA is developing the next generation of Space Professionals
GPIM
13 April 2015
OTB
STP-Sat4
STP-Sat5
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited.
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