P.Neal 31st Space Symposium Tech Track...
Transcript of P.Neal 31st Space Symposium Tech Track...
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015 1
IMESA-R
IMESA-RIntegrated Miniaturized Electrostatic Analyzer – Reflight
USAF Academy
Principal Investigator: Geoff McHarg719 333 2460
Dr. Parris NealCadet First Class Alex Strom
Cadet First Class Nikolas Taormina
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015
iMESA-R: A space weather constellation
Four inexpensive space weather instruments Each instrument provides two measurements
• Low energy plasma (Electrostatic Analyzer)• Radiation (Dosimeter)
Low size, weight, power (SWAP)• 10x12x4.5 cm• 2.1 W without dosimeter, 2.5 W with dosimeter
DoD Space Test Program (STP) providing flights on four different spacecraft
• Green Propellant Infusion Mission (GPIM)—FY16• Orbital Test Bed (OTB)—FY-16• STPSat-4—FY-17• STPSat-5—TBD
First DoD space weather constellation• 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)
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iMESA-R flight instrument for GPIM
iMESA-R Constellation with four concurrent satellites
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015 3
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
• Loss of GPS lock• <50% availability* during severe scintillation
• Loss of SATCOM 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
Knipp, Understanding Space Weather, 2011
Van Allen Radiation belt image created using data from NASA Van Allen Probes: Note emergence of third
transition belt: Image Credit APL, NASA
* For LPV-200. Seo, J, PhD thesis, Stanford Univ, 2010
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015 4
Heritage and Future
Technology patented by USAFA Development funded by AFOSR and AFRL IMESA launched on:
• MISSE7(ISS) iMESA 2009-2011 = 1st data collect• STP-H4 MESA launched Aug 2013 = 1st reflight• STPSat-3 iMESA launch Nov 2013= 2nd reflight
Mature hardware, software, electronics• Demonstrated success on three missions
Future:• GPIM Launch Mid-2016• OTB Launch Mid-2016• STP-Sat 4 Launch Read Aug 2017• STP-Sat 5 TBD
iMESA STPSat-3 Credit Ball Aerospace
MISSE7 Credit:NASA
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015
STPSat-3 IMESA-R Data
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Top panel: raw data product: energy-time spectrogram
• Density increases into sunlight
• Energy increases into sunlight
2nd panel down: Ion Temperature
3rd panel down: Ion Density Bottom panel: derived
spacecraft charging• Energy varying over day-
night cycle between 25-40 eV
Issues:• Data drop out over portion of
orbit• Temperatures not well resolved• EMI due to power converters
STPSat-3 Data: iMESA data product for one orbit 17 Feb. 2015
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015
Changes for iMESA-R flights 3-6
New electrostatic analyzer (ESA) design• Improved temperature measurements• Reduces number of plates—ease of manufacture
Switchable range on ESA• Allows for different host S/C charging
Programmable gain amplifier• Assures data collection during entire orbit• Higher transimpedance amplifier gain
New power supply design• Reduces EMI• Change of one power supply allows flights on
many different satellites Added dosimeter
• Allows ionizing radiation monitoring Rewrote software
• Assures modularity and future upgrades
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Single mezzanine bus: -6dB noise reduction
New ESA Design
ions
Collection Anode
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015
iMESA-R Design Philosophy
Multi-disciplinary• 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• Reduced cost• East of integration• Requires space qualification
“Good enough” versus “gold standard” measurements• Numbers count in terms of improvement to model output• Small SWAP minimizes host S/C impact and increases
Evolutionary design changes• Pick a basic technology• Develop on-orbit flight heritage—learn as you go• Change when needed, not because you can
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DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015
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
• “String of pearls”• 90º inclination• 1 launch
B: 10x satellites @ 350 km• “String of pearls”• 90º inclination• 1 launch
C: 25/5/1 Walker Constellation @ 500 km• 60º inclination• 5 launches• 5 satellites per launch• ~1-10 year lifetime
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Example 25 satellite Walker Constellation
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015
Scenario A,B (“string of pearls”) Vertical propagation of information
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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
(A) (B)
GPS-TEC only GPS-TEC + Sats @ 500 km
GPS-TEC + Sats @ 350 km
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015
Mean height of F2 peak improvement quantification
∑
1∑ 2
∑ 2
• Various metrics can be used to quantify improvement by adding IMESAs
• Metrics can depend on conditions – position, time, geomagnetic activity
• 25 IMESAs improves RMS to ~10 km
• 25 iMESAs improves Skill score to > 75%
Without IMESA
With IMESA
RMS deviation of hmF2 (global sum) Skill score of hmF2 (global sum)
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015
iMESA-R Mechanical Overview
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
• Keying features on boards• Easy integration into CubeSats (for future missions)
Modular structure design to be barnacle mount or panel flush mount• Easily accessible Programming ports in either configuration
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PC-104 Board Size (with Keying Features)
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015
iMESA-R Exploded View
Enclosure Plate
Connector Ring
Brains Board
Lower Mounting Enclosure Heads Board
Assembly
Upper Enclosure
RBF Cover
Programming Port Blanking Plate
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DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015
Hardware Simplified Block Diagram
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= Switchable gain amplification chain
= iMESA-R peripherals
= Data and command pathways
=Signal paths
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Simple heritage code design Rewritten from scratch for OTB &
GPIM IMESA-Rs Minor changes anticipated to
accommodate μcontroller change
Command processing
Sweep processing
Spacecraft communication
Software Block Diagram
DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. 13 April 2015
iMESA-R Summary
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 OTB STP-Sat4 STP-Sat5
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