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GeoCarb Mission Update
IWGGMS 16
Berrien Moore III
Sean Crowell
GeoCarb Mission: Overview
The GeoCarb Mission is designed to collect
observations of the column averaged concentrations of
carbon dioxide (CO2), methane (CH4), and carbon
monoxide (CO), and solar induced fluorescence (SIF)
from geostationary orbit (GEO) at a spatial resolution of
5-10 km over the Americas between 50º North and 50º
South Latitudes as a hosted payload on a commercial
communication satellite.
The Goal of the GeoCarb Mission is to provide
observations and demonstrate methods to realize a
transformational advance in our scientific
understanding of the global carbon cycle.
GeoCarb is an international effort!
Science Hypotheses
1. The ratio of CO2 fossil source to biotic sink for CONUS is
~4:1
2. Variation in productivity controls spatial patterns of
terrestrial sinks
3. Amazonian ecosystems are a large (~0.5-1.0 GtC/y) net
sink for CO2
4. Larger cities emit less CO2 emission per capita than
smaller ones
5. Amazonian ecosystems are a large (~50-100 MtC) net
source for CH4
6. The CONUS methane emissions are a factor of 1.6 ± 0.3
larger than in EDGAR and EPA databases
GeoCarb aims to fundamentally advance our understanding of
how the carbon cycle behaves on regional scales.
Baselin
e M
issio
nT
hre
shold
Mis
sio
n
Req ID
PLRA
Project Level 1 Requirements Baseline Threshold Expected
4.1.1.a /
4.1.2.a
Retrieve estimates of the column-averaged dry air
mole fractions XCO2, XCH4, XCO and SIF from
space-based measurements over cloud-free scenes
XCO2,
XCH4,
XCO, SIF
XCO2,
SIF
XCO2,
XCH4,
XCO, SIF
4.1.1.b.a /
4.1.2.b.a
The bias corrected, clear-air, multi-sounding GeoCarb
retrieval estimates for XCO2 will demonstrate multi-
sounding precision better than
<0.3% <0.6 % 0.2%
4.1.1.b.b /
4.1.2.b.b
The bias corrected, clear-air, multi-sounding GeoCarb
retrieval estimates for XCH4 will demonstrate multi-
sounding precision better than
<0.6% N/A 0.4%
4.1.1.b.c/
4.1.2.b.c
The bias corrected, clear-air, multi-sounding GeoCarb
retrieval estimates for XCO will demonstrate multi-
sounding precision better than
< 10% or
12 ppb
(whichever
is greater)
N/A 8%
4.1.1.c
4.1.2.c
Retrieval estimates of solar induced fluorescence
(SIF) with NESR (W/m2/µm/sr)
<0.75 <1.0 <0.5
4.1.4.a Geostationary orbit longitude 85º W ±20°
N/A 103º W
4.1.4.c Space-based measurements shall have spatial
resolution at the sub-satellite point (single sounding)
< 60 km2
<100km2
< 60 km2
Key Level 1 Requirements
At IWGGMS 15, We Discussed the
Instrument Simplification
GeoCarb: Baseline Instrument PDR
Door Assembly
Entrance Baffle
Star Trackers
Survival Heater Electronics Box (SHEB)
Electronics Tray- GeoCarb Electronics Box (GEB)- Focal Plane Electronics Box (FPE)- Autonomous Star Tracker Electronics (ASTE)- Decoder Electronics Box (DEB)- Cryocooler Electronics (CCE)
Main Bench
PZT Strain Gauge Pre-Amp
Cryocooler Compressor & Cold Head
Spectrograph
S/C Nadir Panel
South Radiators
Heat Pipes not shown
North Radiators
X
Y
E
W
N
S
Z (nadir)Inertial Measurement Unit
Simplified Instrument Overview
Entrance Baffle & Door Assy
Nadir Panel Mounted Components- GeoCarb Electronics Box (GEB)- Focal Plane Electronics Box (FPE)- Star Tracker Electronics Unit (STEU)- Decoder Electronics Box (DEB)- Cryocooler Electronics (CCE)
Cryocooler Thermomechanical Unit
Spectrograph
S/C Nadir Panel
SouthRadiators
NorthRadiators
+Z (nadir)
S (+Y)
E (+X)
W
NDoor Assembly
Entrance Baffle
Main Bench
Scan Box Assy
Spectrograph Assy+Z (nadir)
S (+Y)
E (+X)N
W
Telescope Assy
Optics PackageStruts, 6X
Star TrackerOptical Heads
Single slit, 4-Channel IR
Scanning Littrow Spectrometer Bands: 0.76𝝁m, 1.61𝝁m, 2.06𝝁m
and 2.32𝝁m
Simplified Instrument
• Optical redesign: reduction of SNR from smaller aperture
area - doubled stare time to meet SNR reqts– SNR has margin in all channels, despite the presence of increased
noise from thermal glow
– Areal coverage rate retained by removal of double sampling
• Removal of Secondary Solar Calibration Drum: redundancy
to assess changes in primary diffuser – already planned
lunar observations will be sufficient– Lunar observations will be used to assess changes in the calibration
over time. This methodology has been demonstrated by OCO-2.
Working with lunar cal experts to adapt the OCO-2 approach for
GeoCarb sampling
• Removal of IMU: expected pointing knowledge is reduced by
~0.1km, but it still meets MDRA requirements
We meet all Level 1 requirements and satisfy the mission hypotheses
with the Replanned Project, though with some reduced margin
Mexico City: OCO-2 and GeoCarb
A Day in the Life of GeoCarb
Host Spacecraft
• Working with SES to ensure
maximum compatibility of
GeoCarb with candidate host
spacecraft – Enveloping candidate spacecraft
environments
• Mechanical, thermal,
EMI/EMC, and contamination
– Accommodate 100V spacecraft
busses
– Simplifying instrument to
spacecraft interfaces
– Simplifying satellite integration
and test operations
– Streamlining the instrument
concept of operations
GeoCarb Instrument
Nadir Deck of Comm Satellite
E, +X
W
NS, +Y
Z (nadir)
System Data Flow Block Diagram
Ground ICDs are preliminary at PDR, baselined at CDR
Organization and External Interface View
Also, At IWGGMS 15, We Discussed
the Move to a Firm Fixed Price
Contract with Lockheed Martin for the
Instrument
This was to occur 17 July 2019 at the
It Did Not Happen
Bob Dylan: 2016 Nobel Prize in Literature
• "for having created new poetic
expressions within the great
American song tradition”
• The Times They Are a Changin’
• So too for GeoCarb
• Confirmed for Phase C on 27
December 2019 with Associated
Necessary Changes in Program
Management
NEW Team Organization – Phase C-D*
*GeoCarb Phase E-F team organization will emphasize OU management and is under development.
GeoCarb Project
Science Mission Directorate
PI OfficeProject Management Office
Code 422
Systems
Engineering
Safety & Mission
Assurance
Instrument Developmentt S/C
Host
Earth System Science Pathfinder
Program Office
Business
Management
Goddard Space Flight Center
Code 100
Flight Projects Directorate
Code 400
Earth Science Projects Division
Code 420
Earth Science Division
Flight Programs
Assoc. Dir. Flight
Program Executive
Science Research
Assoc. Dir. Research
Program Scientist
Public CommContracts
Ground Systems and Mission
Operations
NASA Administrator
Management Direction
Funding and Programmatic Direction Institutional Direction
Financial & Business Ops
Focal Plane
I&TDiscipline Engineering
Project Science
Science Team
Instrument MA
Instrument ScienceInstrument Ops
Center
Science Ops Center
S/C Ops and Communications
GeoCarb Data Ops Center
Distributed Active Archive Center
Contracts
Lockheed Martin Advanced
Technology
Center
University of Oklahoma
Langley Research Center
Colorado State University
Ames Research Center
Goddard Space Flight Center
NASA HQ
SES-GS
Science Algorithms
L2 Validation
L0/L1
L2 Development
Launch Services: In FLUX
• Launch services are provided by SES– Procured and managed by SES separately from the Spacecraft contract
• SES has recent experience with a variety of commercial launch vehicles:– SpaceX (Falcon 9)– Ariane 5 ECA– Soyuz– Proton Breeze M
– Launch services include:• All applicable licensing and permitting• TIMs and applicable reviews• Launch site integration and testing• Launch and early orbit support
Falcon 9Ariane V
ECA SoyuzProton
Breeze M
Here At IWGGMS 16, We Can Report
that We Believe that GeoCarb Is
FINALLY in a Good and Realistic
Position to Move Forward.
Near Term Challenge is the “Slit
Homogenizer” and the Longer-Term
Challenge is Schedule
PROGRESS
SLIT HOMOGENIZER
Initial Modeling Studies
• Initial work showed that a slit homogenizer was
necessary to meet baseline science requirements
Percentage of obs passing
quality filter
Scatter before filtering
Scatter after filtering
• The brightness variation across the slit “skews” the ISRF center of mass away
from the uniform illumination ISRF, which causes unresolved forward model
errors in the simulated radiances -> biased retrievals
Illumination Patterns
(Partially Obscured Slit)
ISRF Errors
(O2 A-band)
Without Slit Homogenizer With Slit Homogenizer• Errors grow with scene
albedo variation
• Number of good
observations decrease
with scene albedo
variation
• Both more quickly without
the slit homogenizer
• Atmospheric modeling
showed mission
objectives are attainable
w/o homogenizer
Slit
Entr
ance
Slit Exit
Slit homogenizer
performance model
was developed in
conjunction with and
validated by testing
of the CarbonSat
prototype
homogenizers
Testing of Prototype Devices at ITO
• Two vendors were selected to make three depths
(0.5mm, 1mm, 1.5mm) of homogenizer (each), yielding
six different options for an eventual flight model
• Each of the prototypes was shipped to ITO for
performance testing – knife edge moved across the slit
to provide high resolution imagery of response of SH to
partially obscured slit
• Main results:– Performance mostly independent of manufacturer
– Performance dependent on band and depth (as predicted)
– Significant polarization dependence in the response to
illumination
– Slit image width is a strong function of the polarization,
particularly in the 1.6um band
– Throughput also a strong function of the input illumination
polarization (and band)
20.01.2016Universität Stuttgart – Institut für Technische Optik 5
Test set-up - Alignment
Alignment laser
Fully Illuminated 50% Obscured
Perf
orm
ance R
esults f
or
Weak C
O2 B
and
H pol
V pol
Slit homogenizer model was updated to incorporate the
effects of the coatings in the two polarizations – the gross
effects were reproduced
H pol
V pol
Simulation Strategy
• We decided to employ the existing end-to-end simulator to assess the tradeoffs for the entire GeoCarb FoR
• Divide the slit into 12 sub-slits using– High resolution (500m) surface albedo– High resolution clouds from GOES– High resolution surface elevation data
• Create a simulated radiance for each sub-slit with an ILS that includes the effects of the slit homogenizer (or lack thereof)
• Perform retrievals on the scene total radiances with – ILS that accounts for polarization response of instrument
with/without the slit homogenizer– Polarization model that represents slit homogenizer (or none)– Scene average surface elevation– Imperfect meteorology/clouds/etc– Noise from instrument model (now with polarization dependence
and throughput dependence from SH)– Polarized surface
Overall Results
L1 Reqt No Scene
Inhomogeneity
With Slit
Homogenizer
Without Slit
Homogenizer
Total land soundings 32681 32681 32681
Total # Converged 13931 13574 11724
% Good Soundings
(rel to total)*
23% 21% 15%
% Soundings Lost
due to SI
N/A 2% 32%
CO2 Error Std
(ppm)
1.3 0.9 1.1 1.3
CH4 Error Std (ppb) 12 8 8.3 7.8
CO Error Std (ppb) 10 2.9 3.3 3
• Though we “meet” the uncertainty requirement without the homogenizer, there
would be no margin for other error sources
• With a roughly 25% “pass” rate through the quality filter, and about 4M soundings
per day, the homogenizer would yield about 60K more soundings per day.
ADDITIONAL PROGRESS
“Day in the Life” Test of Algorithms
• Successfully ran a day’s worth of GeoCarb
simulated radiances through L2, resulting in ~318K
good quality retrievals over the western
hemisphere
• Average processing time: ~8 minutes per sounding
– RT speedups are in progress
Solar-induced chlorophyll fluorescence (SIF)
• New retrieval algorithm, GASBAG,
written from scratch – based on
established OCO/GOSAT concepts– [Frankenberg et al. 2011, Köhler et al. 2015]
• Can utilize both physics- and data
driven-based approaches for the
retrieval– Produce equivalent results for clear-sky
scenes
• Algorithm successfully
employed for early OCO-3
assessment of SIF (and
other single-band retrievals)
(JPL press release, 2019/7/12)
OCO-3 SIF over Azerbaijan
Solar-induced chlorophyll fluorescence (SIF)
• Physical vs. data-driven retrievals
– Physics-based retrieval interprets cloudy
scenes as having (unphysical) negative
SIF
– Data-driven retrieval ”sees” clouds as
having zero SIF
– Both are wrong, but consistent with
the assumptions of the algorithms
• Cloud screening is part of L2 SIF
data production, thus relies on tested
and tried cloud screening algorithms
• SIF algorithms are ready!
A Great Job Opportunity
We seek a teamwork-oriented individual who will serve as OU’s local expert on the
GeoCarb instrument. Duties will include:
• Supporting the development and testing efforts of the Lockheed Martin instrument
team;
• Supporting pre-flight calibration activities;
• Supporting the verification of instrument performance and knowledge requirements;
• Supporting the project science by helping to ensure that the instrument
performance meets the high-level science requirements;
• Developing instrument operations plans at OU for implementation after launch; and
• Evaluating and monitoring instrument performance and leading anomaly
investigations during mission operations.
The position will involve regular travel to work with the instrument team on site in Palo
Alto, California, USA.
The successful candidate will possess a minimum of a Master’s degree in earth
science, physics, engineering, astronomy, or a related field with experience in
characterizing optical systems as well as a deep understanding of remote sensing.
Overall Summary
• GeoCarb will make daily observations of XCO2, XCH4,
and XCO over the western hemisphere in order to
constrain local to continental surface fluxes
• After numerous challenges, GeoCarb is on a good path
programmatically and technically
• Hosted payloads are tough!
• Science algorithms and the data processing pipeline are
maturing
• Our concept of operations is baselined using odd/even
day strategy
• We are looking for a great instrument scientist to support
the development and operations effort at the University
of Oklahoma!
See You at IWGGMS 17 and at Launch!!!!!
VIELEN DANK
THANK YOU
34–31CDR 34 – L2 Validation– January 29-31, 2020
Backup
LM Instrument Org Chart – May 2020
5.3 Mechanical Lead
Brad DeLima 5.8 Integration and Test
Phil Tung
5.3 Instrument Lead
Cathy Chou
5.5 Software Lead
Noelle Nguyen-Phuc
5.1 Finance and Business Ops
Barbara Richardson– Contracts
Carol Brosious – Finance
Svetlana Teplitsky – Planner
Emilie Schott - Planner
Terry Wicks – SC manager
Travis Burdette– Sub
John Gamble – Sub
David Schiff – IT Systems
Heidi Shaylor – CM
Instrument Manager
5.1 D L Hoffmann
Claude Kam - CAM
5.4 Thermal Lead
Rose Navarro
-Dave Akin
-Gwen Gradwohl
-Craig Hom
-Buck Holmes
-Deborah Hudson
-Jessica Sun
-Roel Vanbezooijen
-Paul Zhu – M&P
-Eric Dixon
-Joe Mobilia
-Diana Pang
-Alex Petrovsky
-Riza Bravo
-Ross Yamamoto
-Rodrigo Zeledon
-Craig Farless
-Willie Huang
-Bruce Imai
-Ray Yu
-Lomita Rubio
-Mengie DelaCruz
5.1 Instrument SE
Brett Allard
-Alyssa Ruiz-Brandon Chan
-Roger Chevalier
-Donovan Kelly
-David Mansir
-Phil Tung
-Constantine Orogo
-Dennis Wong
5.6 Electrical Lead
Chris Edwards5.6 Focal Plane
Tony Magoncelli
5.2 Instrument MA
Armando Cortez
Swathy Karuppaian – SQA
Donald Cooper – Safety
Commercial Civil Space
Director
Adrian Cuadra
OU Program
Berrien Moore
Shelly Finley
5.1 Instrument Scientist
Eric Burgh
-Margaret Shaw-Lecerf
-Paul Schweiger
-Torben Andersen
-Test Leads TBD
NASA GSFC
Todd King
Adam Matuszeski
5.1 SW Systems
Oversight
Noelle Nguyen-Phuc
Consulting Support
Gary Kushner
What are our objectives and criteria?
• Main goal: go/no go on retaining the slit homogenizer in
the baseline
• Considerations– Level 1 Requirements
• Baseline: Multisounding Precision of 1.3ppm (CO2), 12ppb
(CH4), 10ppb or 10% (CO)
• Threshold: Multisounding Precision of 2.5ppm (CO2) (no
requirements on CH4, CO)
– What about sampling?
• Goal was to get a good sample in each 2x2 degree lat/long
box over a relevant time period – hopefully every day, but at
least once per week after cloud screening
– We have to weigh simulated performance against
implementation risk: alignment tolerances, scattered light, other
unknown unknowns
Synthetic
Retrievals
Atmospheric
inversion model
Inferred fluxes
“End to End” Simulator
Level 2 Req’ts
Instrument Performance Model
Level 1 Req’tsMission Objectives
Simulated
Spectra
Level 3/4 Req’ts
Radiance:
� = � ∗ � �⁄
Solar
Zenith Angle(SZA)
Satellite
Zenith Angle(ZA)
�
� = � cos � � � ∗ �
� = 1
cos � � �+
1
cos � �� = aerosol optical depth
ℎ�
�
W/m2/sr/µm
Photons/sec/m2/sr/µm
AW etendue
Photons/sec/µm/pixel
Instrument Line Shape
Photons/sec/pixel
Throughput à
component efficiencies
Individual exposure time
12 co-added exposures (Nf)
à Gain in SNR
Photons/pixel
Warm optics à
thermal emission
� � � =�
� + � ∗ �
N0 à read noise
and thermal background
N1 à instrument response
12
Simulation Strategy (cont)
• Retrieval results are then– Quality filtered using the same techniques that are applied for OCO-2/3
operational products– Bias corrected using the same techniques that are applied for OCO-2/3
operational products (assume known truth for all available soundings -optimistic)
• The quality filtered, bias corrected products are the best representation of the data that 90% of the science community will use (and hence the right data set to look at for this purpose)
• Perform this for 1) no scene inhomogeneity, and scene inhomogeneity included and 2) including a slit homogenizer or 3) not including a slit homogenizer
• Metrics– Number of good quality soundings– Error scatter of good quality soundings– Observational coverage – Regional scale biases – these have been shown to be the main driver of
accuracy of flux estimates
• Not included: instrument calibration uncertainties, spectroscopy errors, systematic errors from scattered light and other instrument sources beyond the scene inhomogeneity effects
Summary: Slit Homogenizer
• Global statistics tell us the throughput and errors are better
with the slit homogenizer
• These differences occur in the regions that are tied to key
mission hypotheses – Amazonia
• Excluding concerns about schedule, implementation,
calibration, and characterization, we recommend keeping the
slit homogenizer in the design
• Further potential research items– Would including an ILS fit parameter in the L2 retrieval alleviate
some of the trace gas retrieval errors in the absence of a slit
homogenizer?
– How does the instrumental polarization knowledge requirement
play into our understanding of these errors?
– How do these errors average down spatially?
• Cloud-free limited area experiments near Lamont and Manaus
indicate significantly better results with spatial averaging.
Solar-induced chlorophyll fluorescence (SIF)
• Retrieval validation (physical only)
– For clear-sky scenes on land (no
aerosols, no clouds), the true bottom-
of-atmosphere (BOA) SIF is fully
recovered by the algorithm
– Retrieval errors in simulations due to
clouds and aerosols are well-
understood
– After cloud-screening, SIF
errors are small up to
moderate aerosol loadings
(AOD ⪅ 0.2), consistent
with literature
Instrument Simulator Development
OCO-3 Observations per 5x5deg Area - 201406
OCO-2 Observations per 5x5deg Area - 201406 GeoCarb Observations per 5x5deg Area - 201406
Advances in instrument simulators allow for more direct comparisons of OCO and GeoCarb data. Here, we show observation counts aggregated over a single month for OCO-2, OCO-3 and GeoCarb. Note the difference in color scale between the GeoCarb and OCO plots. As a result of its ability to scan more than once per day, GeoCarb obtains more than 60x more observations than OCO over the Americas