1 The "Boreas" concept for imaging polar winds from the Iridium-NEXT constellation Dennis Chesters/NASA, Lars Peter Riishojgaard/JCSDA August 2008

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The "Boreas" concept for imaging polar winds

from the Iridium-NEXT constellation

Dennis Chesters/NASA, Lars Peter Riishojgaard/JCSDA

August 2008

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Goddard Space Flight Center Competition Sensitive

Busted Forecasts

5-day forecasts in the mid-latitudes are "busted" every month

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Sensitivity to Arctic Winds

Forecasts are "busted" by the effects of unobserved arctic disturbances, such as the effect of "Albert clippers" upon eastern N. America

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Science Objectives

• Medium-range weather forecasts can be improved using satellite-based polar wind measurements – Successful science demonstration by JCSDA/ECMWF of improved forecasts ("no-busts"

and accurate hurricane tracks) from MODIS polar overpasses that measure mid-tropospheric winds using the 6.7 micron water vapor channel

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Feature-tracked winds - GEO + MODIS

gap

MODIS

MODIS

GEO's

gap

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Impact on Medium-Range Forecasts

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Economic Benefits of MODIS Polar Winds

Potential Application/Benefit Marginal (Additional) Benefit

using 2007 prices and level of activity

Evacuation reduction in hurricane tracks $12M/year

Efficiencies in polar flight fuel consumption $15M/year

" Economic Benefits of Polar Winds from MODIS and GOES-R Winds ", R. Reining, J. Sterling, G. Dittberner and E. Miller, MITRE/NESDIS study, AMS Annual Meeting, January 2008

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Mission Need

• Drift winds are not observable in the arctic from GEO

• No mid-IR water vapor channel on VIRS/NPOESS in the next decade

• Single LEO satellite overpass of the pole is too infrequent

• Need frequent satellite images of pole in mid-IR water vapor channel and thermal window– EITHER: dedicated "GOES to the pole" in Molniya orbit (GOES-like $250M mission)

– OR: LEO guest imagers swarm the pole ("guests" on Iridium, <$60M instruments)

• Relevance: societal benefit from improved weather forecasts

–Un-met needs at NOAA, FAA, DoD for arctic winds

–World Meteorological Organization (WMO) future vision calls for satellite-based polar winds

–Research-to-Operations

• "Venture class" NASA mission– Focused Earth Science

– Flight of opportunity

– <$100M

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Mission Opportunity

• Iridium LLC is seeking science payloads for the next generation constellation– Launch, operations, and data delivery infrastructure built-in

– Mass production = low unit cost

• Orbit parameters– 11 satellites @ 780 km in 6 planes @ 84 degree inclination @ 11 minute overpasses

• Launch vehicle -- commercial multi-sat launches

• Launch Dates: Iridium LLC plans for 2013 though 2016

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Illustration of the six Iridium orbits populated with 66 satellites. Footprints have been simulated for two side-looking cameras on each satellite. The camera footprints converge above 60 N, providing pixels that can b e assembled into a complete image of the polar cap every 9 minutes.

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Current Mission Concept

• "Boreas" Instrument -- small, robust, autonomous IR pushbroom imager– Uncooled microbolometric thermal IR array

6.7, 8.5, 11 & 12 micron bands, 2 km resolution, ~15 min cadence

– Miniaturized, autonomous attitude determination, milliradian accuracy

– Iridium-specified envelope: <25 kg, <50 W, <1 Mbps, <0.2x0.3x0.5 m

– "Bolt and go" simplicity, 5 year design life with graceful degradation built-in

– Can lose 30% of sensors before mission is impaired --> 15 years of operations

• Minimal Constellation– 3 orbits each half-populated with 4 imagers -- winds 6x per day

– "Pathfinder" development -- launch one early (2013) & then build the rest (2016)

• Cost Estimate (<$60M for instrument development & production)– <$20M NRE for first instrument production and testing

– <$3M per GFE instrument -- industry builds 14, Iridium flies 12

• $TBD– Cost of launch, operation, data delivery from Iridium LLC

– Cost of automated wind determination at a TBD-operated ground station

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Small Thermal IR Microbolometer Camera

• 640x480 focal plane array• +/-0.05 C NEDT @ 30 Hz• 100x TDI for more signal• flown at Mars for 7 years

• 3 Watts• 126 gm• <7x7x7 cm

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Miniature Star Tracker

• 300 gm• 3 Watts• <6x6x8 cm• +/-0.3 millradian @ 1 Hz• “lost in space” recovery within 3 seconds

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3 Cameras & 2 Star Trackers per“Boreas” instrument

• 3 wide-FOV cameras for horizon-to-horizon imaging• 2 star trackers pointing 90 degrees apart• Field-programmable gate arrays to handle data• 4 IR strip filters (not shown) at 6.7, 8.5, 11 & 12 microns• 15 kg, 10 W, 0.6 Mbps in a small package

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4 Boreas in each of 3 Iridium orbits

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Flexible Mission Coverage Scenarios

Scenario-3 smoothly sample 60-70 N- 3 satellite wind-triplets, 9 min apart- phased polar overpasses- 1 or 2 instruments busy at any time- 90 minutes data per cap-scan- observations of pole 90% duty cycle- <4 hr gap in observations at 60N- see figures

Scenario-1 for "snapshot" imagery- 3 satellite wind-triplets, 9 min apart- simultaneous polar overpasses- 9 instruments busy at same time- 30 minutes data per cap-scan- observations of pole 30% duty cycle- <5 hr gap in observations at 60N- not shown

Scenario-2 for less bursty imagery-3 satellite wind-triplets, 18 min apart- simultaneous polar overpasses- 3 instruments busy at same time- 50 minutes data per cap-scan- observations of pole 50% duty cycle- <5 hr gap in observations at 60N- not shown

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Robust Features of Boreas on Iridium

• Technologically Ready– Microbolometric imaging 10 years old

– Microbolomer camera orbiting Mars

– DOD funded micro star trackers

• Simplicity– Bolt & go design

– No moving parts

– No cryogenics

– No calibration sources

• Redundancy– 3 independent cameras per instrument (left/center/right)

– 2 independent star trackers per instrument (left/right)

– 3 orbits @ 60 degree intervals

– 3 instruments + 1 spare per orbit

– 12 instruments to orbit + 2 spares

• Risk minimization– Protoflight 2 years before group launches

– Mass production, integration & testing

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Boreas-on-Iridium Applications

• Application Areas– Weather, Disaster Management, and Air Quality

• Potential Applications– Improved weather forecasts of storm tracks

– Civilian and Military aviation route and air traffic management planning

– Early warning for severe weather conditions while flying polar routes

– Real time tracking of volcanic plumes

• Additional Considerations– Efficiency in real time data dissemination and distribution

• Potential End Users– National Oceanic and Atmospheric Administration

– Federal Aviation Administration

– Department of Defence

– Department of Transportation

– Federal Emergency Management Agency

– State and Local government

– Airlines

– Electric Utilities

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Government/Commercial Collaboration

• Technical readiness– An inexpensive, robust imager with built-in attitude determination can be flown on

Iridium-NEXT without significantly impacting their commercial operation

– Successful Instrument Design Lab study under GSFC IRAD, February 2008

• Programmatic issues– Iridium LLC has identified a half-dozen potential guest instruments, and is negotiating

– NOAA is formally soliciting industrial partners to fill un-met needs, February 2008

– NASA's role: do what it does best -- space-borne radiometry

– TBD: a business plan for guest instrumentation between Iridium LLC and governmental customers for high latitude winds

Documents

1 The "Boreas" concept for imaging polar winds from the Iridium-NEXT constellation Dennis Chesters/NASA, Lars Peter Riishojgaard/JCSDA August 2008