HIGH-LATITUDE WINDS FROM
MOLNIYA ORBIT
a mission concept for NASA’s Earth System
Science Pathfinder Program
Lars Peter Riishojgaard
Global Modeling and Assimilation Office/
Goddard Earth Science and Technology Center
Mission overview
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Fly a geostationary-class atmospheric imager in a Molniya
orbit
Aim is to demonstrate capability of time-continuous
coverage of atmospheric imagery and winds for all of the
northern hemisphere (“GOES to the pole!”)
Scientific heritage provided in part by GOES/Meteosat, in
part by the MODIS winds
Mission can help fill the “water vapor gap” between MODIS
and NPOESS (VIIRS FM4)
Potential for a substantial future upgrade to the GOS
Proposal being developed by the Goddard Space Flight
Center for NASA’s Earth System Science Pathfinder
program
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
• Primary science application: High-latitude winds
– Known shortage of high-latitude wind observations
– Mid-latitude forecast busts often have high-latitude origins
– (Winds from MODIS shown to have positive impact especially on
sub-par forecasts)
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Status of satellite wind observations
• No operational satellite winds beyond 55-60 deg latitude
• Polar winds from MODIS (until 2008)
– Data latency is problematic; 4 to 6 hours after real time
– Image refresh problematic; 15 minutes is optimal, MODIS: ~100
minutes
– No water vapor channel on VIIRS (until at least 2015)
– Latitudinal coverage gap between MODIS and GEO winds
• => Need for “geostationary-type” imagery over highlatitude regions; Molniya Orbit Imager is a good
candidate
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Molniya orbit characteristics
• Highly eccentric Kepler orbit
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Apogee height 39750 km (geostationary orbit height ~36000 km)
Perigee height ~600 km
Inclination 63.4 degrees
Orbital period ~11h 58m (half a sidereal day)
• Location of apogee w.r.t. Earth is fixed and stable!
• Platform in quasi-stationary imaging position near the apogee for
about two thirds of the duration of the orbit
• Used extensively by USSR (to a lesser degree by the US) for
communications purposes
• First suggested for meteorological applications by Kidder and
Vonder Haar (1990)
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Example orbit (Molniya 3-53); all areas N of solid line visible from western cusp
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Additional applications for Molniya imagery
• Nowcasting for aviation, shipping, fishery,
exploration users
• Volcanic ash monitoring (aviation safety)
• Polar lows and other intense/rapid weather
systems
– Nowcasting/forecasting
– Development and life cycle
• Global change
– Arctic is a sensitive region and an early indicator of e.g.
climate change
• Sea ice extent and monitoring
• … possibly others (Multi Temp 2005 ?)
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Molniya Orbit Imager
Preliminary data products list
Product
Aerosols/dust/smoke
Calibrated images
Cloud mask
Cloud-top microphysics
Cloud-top pressure/temperature
Fires/hot spots
Land skin temperature
Low cloud and fog
Derived motion (atmosphere)
Sea ice motion
Sea ice temperature
Sea ice concentration
Sea surface temperature
Snow detection (cover)
Volcanic ash product
Channels
VIS, 11, 12
VIS, 3.9, 6.3, 7.1, 11, 12
VIS, 3.9, 6.3, 7.1, 11, 12
VIS, 3.9, 11, 12
3.9, 11
VIS, 3.9, 11, 12
3.9, 7.1, 11 12
3.9, 11
6.3, 7.1, 11, 12
VIS, 11
11,12
VIS, 11
3.9, 11, 12
VIS, 3.9, 11
VIS, 3.9, 7.1, 11, 12
Status
TBD
Core
Core
Intended
Core
Core
Intended
Core
Core
Core
Core
Core
Intended
TBD
Core
High-level mission requirements
• High temporal (15 minutes) and spatial (1 km VIS, 2 km IR)
resolution imagery for all regions of the northern hemisphere for
multitemporal applications and derived products
– a spacecraft in Molniya orbit is the most efficient single-satellite
complement to the geostationary systems to achieve this goal
– Full-disc view every 15 minutes within 60% of apogee
– Special events rapid-scan capability: 1000 x 1000 km in one
minute
• Nominal 3-year mission duration (goal is 5 years: 2010-2015)
– Nominal end of life for MODIS is 2008; no water water channel on VIIRS
until 2015 (earliest possible date); 2010 launch strongly desirable
• Real-time “operational” dissemination of images and derived
products
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Mission implementation studies
• Overall mission design based on series of concurrent engineering
studies by the Integrated Design Capability at Goddard
• Key IDC results:
– Mission is technically feasible and classified as “low risk”
– Total costs of three-year mission: $212M
• Space segment
– Instrument vendor selected
– RFI for spacecraft issued on 04/22 through by the Rapid Spacecraft
Development Office at Goddard
• Ground segment
– NESDIS is helping to draft plans for data processing chain and has
indicated possibility of ground support (Fairbanks station)
– Finland has indicated possibility of ground support (Sodankyla station;
data processing)
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Instrument system requirements (from POD)
Lifetime
36 months (goal: 60 months)
Orbit
718 min Molniya
Visible Channel
0.55-0.80 micron
1 km horizontal resolution
IR Channels
3.9 (3.8-4.0) micron
6.3 (5.8-6.8) micron
7.1 (6.8-7.4) micron
11.0 (10.7-11.3) micron
12.0 (11.5-12.5) micron
2 km horizontal resolution
Radiometric Precision
VIS: SNR 500:1 @ 100% albedo
IR: 0.2 K @300K, 0.5 K @
250K
Radiometric Accuracy
VIS: 6%
IR: 1 K
Field of View
>24 degrees + star field
Time to image a complete scene
<15 minutes
Input Power (baseline)
< 180 W (including 20% cont.)
Mass (baseline)
<136 kg (including 30% cont.)
Volume (baseline)
<0.9 m x 1.2 m x 1.3m
Instrument
• Raytheon selected as partner for baseline ESSP mission
– Design draws heavily on JAMI, a geostationary imager launched
in February 2005 on the Japanese MTSAT-1R satellite
– Main differences are:
• Scan mode (software change)
• Data processing (software change)
• Channels (new filters, different operating mode)
• Radiation environment (minimal impact)
– Flight heritage (low risk)
– Performance meets requirements in almost all areas
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Molniya Orbit Imager
(deployed configuration; Goddard IMDC)
S/C Buss
Ø1.0m x 2.25m
65 kg propulsion
Solar Array
4.0 m² shown
2.98m² required
Dual axis drive
Y
Instrument ACE box
X
Dual Axis
Comm
antenna
Ø0.5m
Active cooler
Instrument Package
Instrument Thermal radiator
Dewar
Z
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Science Team
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Lars Peter Riishojgaard, UMBC, PI
Bob Atlas, GSFC, Simulation/impact experiments
Dennis Chesters, GSFC, Instrumentation, mission
Ken Holmlund, EUMETSAT, Algorithm development
Jeff Key, NESDIS/ORA, Data processing
Stan Kidder, CIRA, High-latitude applications
Paul Menzel, NESDIS/ORA, Cloud applications
Jean-Noël Thépaut, ECMWF, Global NWP applications
Chris Velden, CIMSS/UW, Algorithm development
Tom Vonder Haar, CIRA, Satellite meteorology
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005
Summary
• Molniya Orbit Imager to be proposed to NASA as a pathfinder for
high temporal and spatial resolution imagery for regions beyond
reach of the geostationary sensors
• Numerous applications, both scientific and operational
– Primary initial thrust is numerical weather prediction; many other fields
in Earth Science can benefit
– Data from this mission are directly applicable to 6 of the 9 (and indirectly
to all 9) GEOSS Societal Benefits areas
• The mission concept is steadily maturing; there is still time to
influence this
• The mission is a prime candidate for national (e.g. NOAA, DoD) and
international (e.g. ESA, EUMETSAT, NWS) collaboration
Molniya Orbit Imager, Multitemp 2005, Biloxi MS, 05/17/2005