International Conference on Space Optics 2014
Optical Performance Results for the PCW
Space Technology Development Activities
Frederic Grandmont, Ph. D., Ing.,
Technology Management & Development
Space & Defense Applications
On behalf of the PCW team
© ABB Group
October 14, 2014 | Slide 1
PCW Mission Context
The Earth Seen from GEO Orbit
© ABB Group
October 14, 2014 | Slide 3
PCW Mission Context
The Famed Northwest Passage
Map by Marc Minton
© ABB Group
October 14, 2014 | Slide 4
Context
The Polar Communication & Weather Mission


The Polar Communication & Weather Mission aims at:
1. Provide 24h / 24 h reliable communication and
navigation services for the high northern latitudes
2. Provide continuous imaging over the north similar to
future generation of GEO weather satellites (ex. MTG).
3. Provide data for climate and environmental monitoring
of the Canadian North.
Method:
 Two satellites on a highly elliptical orbit with apogee over
the Northern hemisphere.
 Payloads:
1. 2-way communication
2. Meteorological payload (Multi-spectral imager)
3. Space weather payload
4. Opportunity for additional science payload(s)
considered…
© ABB Group
October 14, 2014 | Slide 5
PCW Orbit

Highly elliptical orbit
(Molniya, Tundra or Three Apogee)

12 hrs orbit

8 hrs observation

4 hrs overlapp

Two satellites out of phase by
half an orbital period

Continuous coverage of the high
northern latitudes in nearly
geostationary position
http://www.asc-csa.gc.ca/eng/satellites/pcw/
© ABB Group
October 14, 2014 | Slide 6
Meteorological Payload
High Level Requirements


Objective:

Cloud pattern, sea ice and aerosol progression

Improved weather forecast in support of ground
operation

CND contribution to WMO.
Instrument: Multi-spectral imager

Field of regard: full Earth disk

21 spectral bands from 0.45 to 14.5 µm

0.5 km (VNIR) to 6 km (LWIR) ground sampling
distance (@ reference altitude1.5 h before/after apogee)

Complete disk imagery – no gaps

Full disk refreshed every 20 minutes or less

© ABB Group
October 14, 2014 | Slide 7
Ability to do regional subsets
Meteorological Payload
List of Bands
From Trishchenko & Garand, 2011
© ABB Group
October 14, 2014 | Slide 8
Meteorological Payload Concept
Main Features


© ABB Group
October 14, 2014 | Slide 9
23 cm aperture (spatial resolution driven)
Scanning approach makes FOV delays uniform:
1. Continuous horizontal scans
2. Stepped vertical scan

Spectral bands obtained by strip filters
placed over a 2D detector (striped FOV)
 3 focal planes needed (0.45-14.5 µm)
 VNIR, SWIR, M/LWIR

SNR improved by time delayed
integration when necessary

Post-acquisition correction of
systematic pointing errors
Full disk scanned
in < 15 minutes
Spatial / temporal coverage equivalent
to 23 low-Earth orbit satellites
Meteorological Payload Concept
Block Diagram
Scene
Hatch
Optical Link
Mechanical
Thermal link
Electrical link
Input Optics
Scanning
mirror
Baffle
M/LWIR MSC
OpticalBench
Dichroic 1
Telescope
SWIR MSC
Dichroic 2
SW Calibration
Hatch
Sun
Diffuser
panels
LW Calibration
Blackbody
VNIR
detector
SWIR
detector
MWIR
detector
ROE
ROE
ROE
Star
Trackers
Telemetry
sensors
Blackbody
controller
Control Electronics
Cooler Stage 1
Filters
Heaters
Scanner
controller
Radiator
Structure
Cooler Stage 2
Mech.
coolers
Bus
DC-DC
Panel
controller
Memory
© ABB Group
October 14, 2014 | Slide 10
Filters
Filters
Bus
Deep
Space
VNIR MSC
Control
electronics
Data
formatter
ADC &
acquisition
control
Cooler
controllers
Bus
Meteorological Payload Concept
3 D View
© ABB Group
October 14, 2014 | Slide 11
PCW Predevelopment Activities (2012-2014)
Critical Items Selected for Breadboard Demonstration



TRL 5 for the telescope:

Launch vibrations

Radiation exposure (coated optics)

Thermal cycling and thermal tests
TRL 5 for the spectral separation (strip filters):

Radiation exposure

Thermal cycling and thermal vacuum tests
TRL 4 for the Multi-spectral
camera assembly (MSCA):

© ABB Group
October 14, 2014 | Slide 12
TRL 5: Breadboard testing in
relevant simulated environment
Commercial-grade Sofradir detectors & coolers
did not allow for vibrations & radiations testing
TRL 4: Breadboard testing
in laboratory conditions.
Telescope Breadboard
28.5 kg
Completed Telescope Ass’y
© ABB Group
October 14, 2014 | Slide 13
Multi-Spectral Camera Assembly (MSCA) Breadboard
10.5 kg
Completed MSCA & FPA Ass’y
© ABB Group
October 14, 2014 | Slide 14
Tests Performed
© ABB Group
October 14, 2014 | Slide 15

Environmental tests (TVAC, vibrations, radiations)

Mirrors roughness & WFE:

Before and after mounting

Before and after thermal cycling

Before and after vibration test

Thermal balance and cooling power budget validation

Imaging quality (MTF)

FOV mapping

Distortion mapping

SNR in each implemented bands and matching to model.

Filter transmittance through radiations

Spectral filters mapping on FPA
Optical Tests Results
Mirror Wavefront vs. Temperature
1)
2)
Test case
0) Ambient - no load
1) Operational cold - thermal control OFF
2) Operational hot - thermal control ON
3) Operational cold - thermal control ON
3)
Wavefront
RMS
0.051
Requ. RMS
0.063
0.110
0.055
0.058
0.063
0.063
0.063
Thermal control allows maintaining the wavefront within the requirement
Filter Transmission

14 bands tested

Sufficient to demonstrate
coating approach good
match to design curves.

Other filters have similar
complexity.
SWIR array
© ABB Group
October 14, 2014 | Slide 18
M/LWIR array
Optical tests results
Optical modulation transfer function
VISNIR 760 nm
MTF - 11.2 µm
100
90
80
Contrast (%)
70
60
50
40
Requirements
30
Image taken with
5x smaller pixels
20
10
0
0
2
4
6
8
10
12
Frequency (cycle / mm)
© ABB Group
October 14, 2014 | Slide 19
MTF meets design expectations
and exceeds requirement
14
16
18
Conclusion
© ABB Group
October 14, 2014 | Slide 21

Canada is looking to improve satellite-assisted
operations in the North.

PCW will not only benefit to Canada but many
northern hemisphere countries

PCW will provide geo-like imagery of the high
northern latitudes every 15 minutes 24 h / 24 h.

ABB is currently leading the optical payload
development in Canada.

The critical technology elements of the met payload
were demonstrated at TRL-5 at the exception of
the camera due to available funding.
Context
The Polar Communication & Weather Mission (PCW)
Problematic:
 Communications are problematic at high latitudes
 Difficult for latitudes > 60°
 Impracticable for latitudes > 72°
 A sizeable fraction of the Canadian North is poorly
serviced
 Quality and availability of weather data are problematic at
high latitudes
 Large view angle from geostationary satellites
 Poor spatial resolution and long atmospheric path
 Has an impact on the weather forecasting at high
latitudes
 Has also an impact on weather forecasting everywhere
else since weather patterns are not stationary
© ABB Group
October 14, 2014 | Slide 23
PCW
Program and milestones

Collaboration between the Canadian Space Agency, Environment
Canada and the Department of National Defence

With support from Natural Resources Canada, the Department of Fisheries
and Oceans, the Canadian Cost Guard, Transport Canada, Nav Canada,
the Department of Foreign Affairs and International Trade, the Department
of Indian and Northern Affairs, and Territorial Governments.

Industrial team led by MDA included MDA, Telesat, ABB, COMDEV,
Magellan, Advantech, SED

Meteorological payload concept definition initially by ABB and
COMDEV team

Phase 0:



Phase A:

Started July 2009

MRR: February 2010

End: March 2011
Technology development activities

© ABB Group
October 14, 2014 | Slide 24
Completed Sept. 2008
Started Nov. 2011, ended March 2014
Meteorological Payload Concept
3 D External View
Science Input port
Baffle
Main structure
Star trackers
Telescope structure
© ABB Group
October 14, 2014 | Slide 25
Radiator with
louvers
Meteorological Payload Concept
3 D Exploded View
Shutter
Primary Structure
Calibration input port
Scanner
Star tracker
Telescope input
port
Shutter
SW Calibration
assembly
Telescope
assembly
Solar Baffle
Multi-spectral
camera assembly
© ABB Group
October 14, 2014 | Slide 26
LW
Calibration
blackbody
Radiator and
Coolers assembly
SC Mounts
Science
Input port
PCW Predevelopment Activities (2012-2014)
Critical Items Selected for Breadboard Demonstration
1.
Telescope

2.
3.
© ABB Group
October 14, 2014 | Slide 27
Mirrors and telescope structure
Multi-spectral camera assembly

Camera thermal enclosure

Thermal interfaces to the cooler

Commercial infrared detector arrays

Camera optics
Spectral separation optics

Dichroic beamsplitters

Spectral filter arrays
Imager Breadboard
Tertiary Mirror
320 mm 
Secondary Mirror
37.5 mm 
Primary Mirror
250 mm 
Multispectral
Camera
Assembly
Heaters
Optical Bench (CFRP)
Dichroic #1
© ABB Group
October 14, 2014 | Slide 28
Multi-Spectral Camera Assembly Breadboard
180 K enclosure
Dichroic 1
Folding Mirror
M/LWIR
FPA ass’y
VNIR detector
Folding Mirror
Thermal
Straps
Dichroic 2
SWIR FPA ass‘y
Multi-Spectral Camera Assembly Breadboard
Pictures of the breadboard
Completed FPA Assembly
Completed MSCA
© ABB Group
October 14, 2014 | Slide 30