15th CASI Conference on Astronautics - ASTRO 2010
4 - 6 May 2010, Toronto, Ont. Canada
PLATFORM FOR THE OBSERVATION OF THE EARTH AND FOR INORBIT TECHNOLOGY EXPERIMENTS (POETE) MISSION CONCEPT
Jean de Lafontaine (a), Jean-François Hamel (a), Alain Royer (b), François Châteauneuf (c),
Christian Proulx (c), Perry Edmundson (d), Brian Moffat (d)
(a) NGC Aerospace Ltd, Sherbrooke, QC, ngc@ngcaerospace.com
(b) CARTEL, Université de Sherbrooke, Sherbrooke, QC
(c) Institut National d’Optique (INO),Québec, QC
(d) COM DEV, Cambridge, ON
Abstract
For the Canadian community, forest fires pose both a scientific challenge – how they impact our climate
and environment – and a socio-economic challenge – how they affect our quality of life, health, economy
and means to fight them. In an effort to help overcome these challenges, the Platform for the Observation
of the Earth and for in-orbit Technology Experiments (POETE) mission concept is proposed. POETE is a
tandem Low-Earth Orbit microsatellite mission concept which has as objectives to provide a reliable and
affordable platform for forest fire detection and monitoring, for complementary scientific experiments on
climate change and global warming and for the demonstration of new space technologies. The POETE
mission would also provide educational institutions with free and open access to the data for the purpose
of space education and awareness on climate change and global warming. The paper presents an
overview of the proposed POETE mission objectives, design and capabilities.
Introduction
On average, about 9,000 fires annually burn 2 million hectares of Canadian forest, mostly in the boreal
zone. They release a wide range of chemical species, including large quantities of greenhouse gases,
smoke aerosol, atmospheric mercury, ozone precursors and particulate matter. Continued warming and
drying of the boreal region will very likely exacerbate this trend1. For the Canadian community, they pose
both a scientific challenge – how they impact our climate and environment – and a socio-economic
challenge – how they affect our quality of life, health, economy and means to fight them. Currently, there
is no system in orbit dedicated to fire detection and monitoring.
The Platform for the Observation of the Earth and for in-orbit Technology Experiments (POETE) concept
is a tandem microsatellite mission proposed to help overcome these challenges. The POETE mission aims
at:
 performing remote sensing of fires and land surface thermal anomalies
 validating a new infrared sensor and system dedicated to fire detection and monitoring from space
 demonstrating new micro-satellite technologies in space
The primary scientific objective of the POETE mission is to provide a reliable and affordable platform for
forest fire detection and monitoring. In this context, the main scientific innovation of the POETE mission,
compared to similar existing and planned missions, consists in an increased spatial resolution and revisit
frequency. The POETE mission would rely on a new generation of highly autonomous and agile
microsatellites which would make it possible to detect, track and quantitatively assess boreal forest fires
and to assist civil authorities in better fighting them.
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The main technological goal of the POETE mission consists in providing a platform through which new
space technologies can be demonstrated in space. One of the technology demonstrations focuses on the
development and validation of innovative sensor and satellite design. The proposed new infrared detector
is a microbolometer-based pushbroom radiometer. Another technology-demonstration experiment would
validate in space an innovative navigation system that relies on the Sun and the Earth magnetic field for
position determination.
Figure 1: POETE Constellation
In addition, the POETE mission concept would provide a platform for complementary scientific
experiments, such as monitoring burnt areas and land cover change and detecting other thermal
anomalies: urban heat island, coal seam fires, burning oil spills or natural phenomena such as volcanoes.
The POETE mission also intends to provide educational institutions (schools, museums, science
exhibition centres, etc.) with free and open access to the data for the purpose of space education and
awareness on climate change and global warming. Finally, the POETE mission would demonstrate
Canadian leadership and capabilities in the realisation of low-cost microsatellites for Earth observation
and security monitoring.
The paper first reviews the POETE mission objectives, which have been put together to answer the needs
of the Canadian forest fire community. Subsequently, the mission design which is proposed to meet the
objectives is presented. The feasibility analysis shows the mission is technically feasible using Canadian
sensor and microsatellite platform technologies.
Mission Objectives
POETE is a space platform and mission concept aimed at conducting Earth-observation scientific
missions with payloads at the Technology Readiness Level (TRL) of 7 to 9 and at demonstrating, in a
relevant environment, innovative technologies at TRL 4-6, in support to future Earth-observation
missions. There are two types of mission elements: scientific mission elements and technological
demonstration elements.
The proposed scientific elements include the following:
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


Detection, monitoring and prediction of greenhouse gases and air pollutant emissions from forest
fires
Monitoring of thermal anomalies and land surface temperature
Education, outreach and awareness in Earth Observation (EO) missions
The value of the scientific mission elements is augmented by the innovative use of several Canadian
enabling technologies, already at TRL 8-9:
 highly agile spacecraft guidance and control techniques allowing across-track scanning and
tracking capabilities
 on-board real-time autonomous detection of hot spots for controlling the satellite tracking system
 highly-autonomous orbit determination and attitude control software
 improved IR microbolometer technology
In addition, it is proposed to simultaneously perform an in-orbit demonstration of low-cost magneticfield-based attitude and orbit determination for small satellites. This technology demonstration mission
relies on components already existing on-board the spacecraft.
Forest Fire Monitoring & Modeling
The POETE mission first aims at preparing a new generation of space-based observation systems by
increasing both the spatial and temporal resolution of the data and by advancing the ground-based
analysis tools that will extract from the data an assessment of greenhouse gases and pollutants emissions.
Therefore, future evolution of the fires and their plumes will be better predicted. The more accurate
assessment of the quantitative parameters derived from the proposed mission will provide reference
validation data for the existing low-resolution (GOES type) and moderate-resolution imager (MODIS
type).
Figure 2: High Resolution Monitoring of the Temperature of the Fire Front
The proposed Forest Fire Monitoring & Modeling mission element thus has three main objectives:
 to deploy a new generation of space-based observatories, characterized by the use of highly
autonomous and agile microsatellites and by the improved spatial and temporal resolution of the
data they will generate, with the objective of detecting, tracking and quantitatively assessing
boreal forest fires and to assist civil authorities in better fighting them
 to support the improvement of ground-based modelling and data analysis for the estimation and
prediction of the emitted greenhouse gases and air pollutants, with the objective of assessing their
long-term impact on the environment, the climate and the health of Canadians
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
to demonstrate Canadian leadership and capabilities in the realisation of a microsatellite bus and a
thermal infrared radiometer using a microbolometer-based pushbroom radiometer.
To meet these objectives, the POETE mission will acquire data from sensors with the following
characteristics:
 at least 6 spectral bands:
o red (VIS) and near-infrared (NIR) bands to estimate fuel types (vegetation index)
o Middle-Wave Infrared (MWIR) to identify forest fires
o three Thermal Infrared (TIR) bands to retrieve skin temperature and anomalies
 high spatial resolution in all bands (≤ 400 m) to resolve spatial characteristics of fires, with
similar swath for all bands
 high temporal resolution to ensure accurate estimation of rate of fire spread
 global coverage of the Canadian territory to provide fire detection capabilities in the uninhabited
Northern regions.
Even if there are strong international efforts for fire detection and monitoring development systems 1, the
spectral, spatial and temporal resolutions of current satellite platforms do not adequately meet the need for
real time detection and monitoring of wildland fires. As described in Table 1, the POETE mission will
provide a substantial improvement over the two most commonly-used space-based systems in forest fire
monitoring: GOES and MODIS. GOES has an almost continuous coverage of the Canadian ground, but
has a poor resolution at the Canadian latitudes. MODIS has a slightly better resolution than GOES, but
has a much larger revisit time. The proposed POETE mission proposes to provide simultaneously a high
revisit time and small ground sampling distance.
Table 1: Comparison of the GOES, MODIS and POETE Capabilities
GOES-12 (East)
MODIS
POETE
MWIR: 3.4 – 4.0
MWIR: 3.93 – 3.99
TIR1: 8.3 – 9.3
MWIR: 3.80 - 4.00 TIR: 10.8 – 11.3
TIR2: 10.0 – 11.0
Spectral channel for fire
TIR: 10.20 - 11.20
TIR: 11.8 – 12.3
TIR3: 11.5 – 12.5
detection (µm)
TIR: 11.50 - 12.50
SWIR: 2.11 – 2.16
SWIR: 1.6 or 2.2 (option)
VIS: 0.55 - 0.75
NIR: 0.84 – 0.88
NIR: 0.84 – 0.90
VIS: 0.62 – 0.67
VIS: 0.60 – 0.67
Channel saturation
MWIR: 337 K
MWIR: 450 K
MWIR and TIR (8.8 µm): 700 K
MWIR 4 km
1 km
400 m
Ground Sampling
NIR
-500m
200 m
Distance
1 km
250 m
200 m
VIS
Swath width
Full Earth disk
2330 km
200 km
Revisit time
30 min
4 times a day
3 to 7 times a day
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2
Smallest Detectable 800 K Fire
2100 m
230 m
50 m2
800 K Fire Area at Pixel
No saturation
11 000 m2
66 400 m2
Saturation
Sensor
In addition, the POETE thermal sensors are designed to have large channel saturation levels, which allow
accurate monitoring of High Temperature Events (HTEs) with a small ground sampling distance.
Thermal Anomalies & Climate Applications
The sensor suite embarked on POETE for forest fire monitoring also enables monitoring of thermal
anomalies and various climate applications:
 detection of pollution events from thermal anomalies that have a major impact on air quality and
the environment (Figure 3)
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
detection of surface temperature for meteorology, hydrology, ecology/agriculture and climate
applications
The proposed mission would regularly provide data on surface temperature of Canadian land mass, inland
waters and adjacent oceans.
Systems providing this type of information with sub-kilometric ground sampling distance at revisit times
of less than three days currently do not exist. POETE would thus greatly contribute to the quality of
available scientific data with a high resolution (400 m) monitoring of the surface temperature at a high
rate.
Figure 3: Monitoring of High Temperature Event from Space – Chiliques Volcano (Courtesy of NASA)
Educational Outreach
The outreach mission element consists in using the POETE mission itself, and the data it will generate, to
foster public interest in space missions, space science and space technology, and contribute to the public
awareness of climate change, global warming and environmental changes as seen from space.
The POETE mission proposes an approach to instil fascination and interest by allowing a direct
participation of the public in a space mission. This strategy is successfully implemented in the Belgian
EduPROBA programme, using the Earth-observation satellite PROBA-1.
Figure 4: Use of Satellite Data in Support to Teachers
Students from primary and secondary schools propose projects related to geography, natural sciences,
history or other subjects in which the acquisition of space-based images (polluted rivers, chains of
mountains, historical monuments, etc.) is required to support or illustrate the arguments. The images are
then commanded to the highly-autonomous and agile POETE spacecraft and delivered to the students. In
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the process, the students learn about space technology and the related fundamental disciplines
(mathematics, physics, etc).
Technological Demonstration
Technology demonstration element consists in the demonstration in flight of low-cost attitude and orbit
determination navigation technology. It aims at validating novel and innovative Canadian technology up
to TRL 6. The main objectives of technology demonstration element are:
 to demonstrate Canadian-developed low-cost attitude and orbit determination module with the
objective of maintaining medium-accuracy attitude and orbit knowledge using measurements of
the magnetic field and Sun presence only4,5
 to advance Canadian expertise in autonomous and low-cost attitude/orbit determination for
microsats and smallsats
 to ensure technology mission element does not drive the design or the cost of the primary
scientific mission by reusing existing sensors on-board the spacecraft.
Mission Design
In order to meet the mission objectives, three mission strategies were investigated. The first strategy,
Strategy A, consists of 2 agile, off-nadir-pointing micro-satellites launched together in the same orbital
plane into a Formation-Flight Configuration. After a 6 month-period in this Formation-Flight
Configuration, the orbital planes of the two spacecraft are separated by propulsive means to reach a
drifting configuration that makes use of the oblateness of the Earth to naturally separate the orbital planes
over a period of 1 year. Once the desired separation is reached, the spacecraft perform a second small
manoeuvre to stop the relative drift and enter the nominal science mission phase.
The second strategy, Strategy B, is made of two spacecraft launched separately and simultaneously
directly on the nominal science orbit. This strategy avoids the need for a propulsion system to perform the
plane separation, but does not allow for a formation flying technological demonstration experiment, as
does Strategy A.
Strategy C consists of a single spacecraft launched on its nominal orbit. This mission concept is obviously
a minimum-cost solution but the achievable revisit time, critical in forest fire monitoring, is greatly
affected by the presence of only one spacecraft.
Figure 5: POETE Constellation Orbits
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In order to select the appropriate strategy, a first mission conceptual design exercise was conducted for
each of the mission strategy, based on a set of user and system requirements established to guarantee the
achievement of the mission objectives.
Based on the performed trade-off analysis, Strategy B (Figure 5) was baselined. With an agreement on the
baseline strategy, the design consolidation activities were conducted for the four main mission
components: the MWIR-TIR payload, the VIS-NIR payload, the constellation orbit and the spacecraft
bus.
MWIR-TIR Payload
The MWIR-TIR payload instrument is a pushbroom scanner that consists in a four-channel filter
radiometer with on-board radiometric calibration capabilities (Figure 6).
Figure 6: MWIR-TIR Instrument Concept
The instrument comprises a Scene Selection Module (SSM) that is used to scan between the internal
calibration blackbody module and the external scene. In addition to the internal blackbody (a cavity-type
device that can be actively controlled to up to ~350 K), the radiometric calibration of the instrument is
ensured by a view to deep space. The optical signal is relayed from the scene to the detectors by an allreflective three-mirror optical system used in combination with dichroics and filtering optical elements.
This anamorphic system delivers a ground sampling distance of 400 m at an altitude of 700 km.
The optical signal is split four ways and filtered to provide the four spectral bands to the detectors: MWIR
(3.4 to 4.0 µm), TIR1 (8.3 to 9.3 µm), TIR2 (10.0 to 11.0 µm) and TIR3 (11.5 to 12.5 µm). One detector
assembly is used for each band. The detector assemblies are based on the use of the INO IRL256
uncooled bolometer linear Focal Plane Array (FPA). Two FPAs are used for each assembly to provide for
a swath of 204 km at an altitude of 700 km. The detector assemblies include proximity electronics for
temperature control and basic filtering of signal in order to ensure optimal performance.
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The instrument includes an electronics module that receives and applies operational parameters from the
spacecraft platform. The electronics module also controls and monitors other instrument’s module
(blackbody temperature control and monitoring, pointing mirror motor control, detector temperature
control, bolometer pixels biasing and reading, data transmission to the spacecraft). The instrument finally
comprises an optical bench that interfaces with the spacecraft platform as well as the other instrument
module. The opto-mechanical approach combines aluminum diamond-turned optics with an aluminum
optical bench for optimal thermal stability.
VIS-NIR Payload
The POETE VIS/NIR Imager is a dual band pushbroom imager that is packaged into two modules: the
camera assembly and the electronics assembly (Figure 7).
Figure 7: VIS-NIR Instrument Concept
The camera assembly has a common fore optics and baffle, and uses dual linear Charge-Coupled Devices
(CCDs) that are combined in a dichroic manner. The CCDs are actively cooled to the required
temperatures. The readout electronics board is housed within the camera assembly to enhance
performance.
The electronics assembly contains the power conditioning electronics and the instrument controller
electronics. Heat from both assemblies is conducted into the spacecraft.
The VIS/NIR Imager has a ground resolution of 200 m, and a signal to noise ratio in excess of 125. The
VIS/NIR Imager has a mass less of than 5 kg, a power of less than 7 W, and a volume of less than 4 litres.
Orbit Design
The constellation is made of two spacecraft launched on 700-km altitude Sun-synchronous orbits with
12:30 Local Time of Ascending Node (LTAN) and 16:00 LTAN (Figure 5). These orientations are
selected to optimize the coverage of Canadian forest fires during the peak of their activity in the
afternoon3.
Considering the agility of the spacecraft, any target located within the coverage area (Canadian territory
between 45 deg latitude and 70 deg latitude) can be monitored between 3 and 7 times per day.
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In the search and detection mode, with the spacecraft pointing nadir not tracking a specific target, the
average revisit time varies between 1 and 2 days depending on the latitude of the target. Based on the
polar nature of the Sun-synchronous orbits, the Northern targets get a better coverage than Southern
latitude targets.
Spacecraft Design
The POETE spacecraft are based on the COM DEV Multi-Mission Microsatellite Bus platform. The
spacecraft dimensions are 60 x 60 x 80 cm and they weigh approximately 95 kg each. They are sized to fit
within the secondary payload envelope of most available launch vehicles from American, European,
Russian and Indian launch providers. This allows the spacecraft to be launched in the most economical
way possible. An image of the POETE spacecraft concept is shown in Figure 8.
The MWIR-TIR and VIS-NIR imaging payloads are shown in the payload bay of the spacecraft, which is
on the +Y face of the spacecraft (top of image). The volume, mass, power and pointing requirements of
the two payloads are compatible with the spacecraft bus capabilities. The Payload Attachment Fitting, or
PAF, which is used to attach the spacecraft to the launch vehicle, is the ring-type structure that is visible
on the –X face (left side of image).
Figure 8: POETE Spacecraft Concept
The spacecraft will fly in a Sun-synchronous Earth orbit with the –Z face pointing in the Nadir (Earthfacing) direction, providing a continuous Earth view for the imaging payloads. The exterior panels of the
spacecraft are covered with solar cells which provide adequate power generation capability for the
payloads and spacecraft systems. The spacecraft has several S-band antennas for command and telemetry,
as well as for downloading the payload data. Alternatively, if a large amount of payload data is to be
collected on a daily basis, the spacecraft can be equipped with an optional high-speed data downlink,
which would allow the entire payload data collected each day to be downloaded to a single ground
station.
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Other Investigated Options
In addition to the baseline design, the POETE project investigated additional ways to improve the
mission, namely the addition of a Short-Wave Infrared (SWIR) channel and the addition of a propulsion
system on both spacecraft.
The main advantage for a SWIR band is the possibility to accurately detect the burnt areas (fire impact
analysis), to distinguish live biomass from dead biomass and soil, e.g. for burn scars mapping, and to
discriminate clouds. The SWIR band allows the flaming ratio estimation, the land cover detection through
smoke plumes (minimum aerosol scattering effect) and the vegetation moisture assessment.
Equipped with an on-board propulsion system, both spacecraft can be launched together on the same
rocket, and then make use of the perturbations induced by Earth oblateness and slowly drift to reach their
nominal scientific mission orbit (Strategy A). The three main advantages of this strategy are (1) a cost
reduction due to the management of only one launch interface, (2) the possibility to cross-calibrate the
spacecraft payloads (both spacecraft looking at the same target at the same time) and (3) the capability to
perform formation flying technological demonstration manoeuvres right after launch, while the spacecraft
are still flying in formation.
While both improvements were investigated, it was found that given the requirements of the primary
science payloads, the capabilities of the considered microsatellite platform and the large design margins
that have to be carried at this phase of the mission, the SWIR channel and the propulsion system could
not be embarked. However, if platform requirements were to change during subsequent mission phases,
the trade-off to include any of these options could be reopened.
Conclusion
The POETE mission concept is proposed in an effort to answer the needs of the forest fire detection and
monitoring community. The unique features of the POETE measurements are their improved spatial
resolution, 400 m without saturation, which will make it possible to detect fires as small as 50 m2 as well
as to retrieve quantitative parameters of fires (effective temperature, area and radiative energy release).
Moreover, the agility and innovative orbit-control capabilities of the POETE mission will significantly
improve the required revisit frequency of a given geographical site, up to seven observations per day,
using an optimal tandem configuration of two microsatellites. In addition, the POETE imaging payload
will include an autonomous forest fire detection system which is a considerable issue for northern regions
of Canada where ground-based or airborne fire detection is lacking or expensive.
The mission design exercise has proven that the mission is technically feasible with Canadian
microsatellite platforms and Canadian sensor technologies. The performance of the mission, based on
affordable technologies, would prove to be a significant improvement compared with the current and
planned missions.
While the mission design is optimized for the latitude of the Canadian boreal forest, it could also prove to
be useful for other countries. In future development phases, partnerships with other countries or agencies,
also concerned with forest fire monitoring should be investigated.
Acknowledgments
The authors would like to acknowledge the support from José Sobrino and Yves Julien, from Universitat
de València, and Françoise Nerry, from Université Louis Pasteur, who contributed in the definition of the
requirements for the mission.
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This study was funded by the Canadian Space Agency through the Space Technology Development
Program. The authors would like to acknowledge the great contribution and support from Martin
Bergeron and Capt. Érik Tremblay from the Canadian Space Agency, who acted as scientific and project
authorities for the study.
References
1
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2
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4
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