Sentinel Convoy: Synergetic Observation by Missions
Flying in Formation with European Operational Missions
Workshop to engage
a wider science community
Dates: 31 October - 1 November 2011
Venue: ESA ESTEC, Noordwijk,
The Netherlands
E-mail (Dr Neil Humpage): nh58@le.ac.uk
Website: www.le.ac.uk/sentinel-convoy-land
Background
ESA are undertaking three studies investigating possible
synergistic satellite missions flying in formation with the
operational GMES and METOP satellites
These three studies are focussed on:a) sea and ice
b) land
c) atmosphere
SSTL, the University of Leicester and Astrium Ltd are
undertaking the second of these studies:
Sentinel Convoy: Synergetic Observation by Missions
Flying in Formation with European Operational
Missions, Focusing on the Land Theme.
Overall Study Objectives
Sentinel Convoy: Synergetic observation by missions
Flying in Formation with European Operational Missions.
To identify and develop, (through thorough systematic
analysis), potential innovative Earth science objectives
and novel applications and services that could be made
possible by flying additional satellites, (possibly of smallclass type), in constellation of formation with one or more
already deployed or firmly planned European operational
missions, with an emphasis on the GMES Sentinels, but
without excluding other possibilities.
In the long-term, the project aims at stimulating the
development of novel, (smaller), mission concepts in
Europe that may exploit new and existing European
operational capacity in order to address in a cost effective
manner new scientific objectives and applications
Overall Study Logic
Step -1 Identification of science gaps that might
be addressed by a “convoy” mission
flying with the Sentinel satellites
Step-2
Identification of candidate mission
concepts that may address the identified
gaps
Step-3
Down-selection of most promising
concepts from list of candidates
Step-4
Detailed technical study of selected
concepts
Step-5
Cost and schedule analysis of selected
concepts
Aims of the Workshop
FOCUS OF THE WORKSHOP
Step -1 Identification of science gaps that might be
addressed by a “convoy” mission flying with
the Sentinel satellites
PRELIMINARY DISCUSSION
Step-2 Identification of candidate mission concepts
that may address the identified gaps
Preparation Material - Contents List
To facilitate the discussions during the workshop, the
following slides provide:Workshop Part 1
1.1 Information on the priority science areas which are
likely to be discussed
1.2 Definition of potential “gaps”
1.3 Parameters relating to the information products
which might be generated from the convoy system
Workshop Part 2
2.1 Examples of some existing and proposed
synergistic missions
2.2 Data on the Sentinel satellites with which the
convoy missions will fly
2.3 Performance parameters which will be relevant to
the mission concepts
2.4 Operational constraints relating to collaboration
with the Sentinel missions
2.5 Definitions of Formation Flying and Constellation
as we shall use the terms in this study
1.1 Priority Science Areas
The following science areas will be highlighted during the
workshop:•
The water cycle
•
The carbon cycle
•
Terrestrial ecosystems
•
Biodiversity
•
Land use and land use cover
•
Human population dynamics
1.2 Gaps
The focus of this workshop is to engage a wider scientific community regarding
the identification science gaps and user needs.
Gaps in capability could include:• The need for data with higher spatial/spectral/radiometric resolution
• The need for more synoptic data collected over a greater percentage of the
Earth’s surface in a given time period
• The need for more frequent observation opportunities over given regions, or
longer time-histories of particular target locations
• The need for observations at novel wavelengths to collect new signatures
1.3 Information Products
Workshop participants are invited to consider the nature of the information
products that would be required to satisfy the identified science gaps
Parameters that will be relevant to the definition and level of the information
products include:
The frequency with which the final product will need to be generated
The frequency or time period over which the individual data sets will be needed
The land area over which the data will need to be collected
The spatial resolution of the data that will be required
The spectral resolution of the data that will be required
The radiometric quality and calibration of the data that will be required
2.1 Examples of Synergistic Missions
•
NASA A-train
– Combining data sets from instruments gives
better understanding of parameters affecting
climate change
•
PREMIER (infrared limb sounder & mmwave limb sounder)
– Earth Explorer 7 Candidate mission will fly
ahead of nadir viewing MetOp satellite.
Synergy of atmospheric observations down to
Earths surface (without cloud)
•
Sentinel-5 Precursor (S5p)
–
•
Will fly with NPP/JPSS Atmospheric
chemistry, with cloud data provided by
NPP/JPSS
Earth Explorer 8 candidates
– FLorescence Explorer (FLEX) and CarbonSat
flying with Sentinel-3
2.2 Sentinel Mission Summary
Sentinel 1 – SAR imaging
All weather, day/night applications, interferometry
x 2 satellites, 693 km, Dawn dusk orbit
2013 / 2015
Sentinel 2 – Multi-spectral imaging
Land applications: urban, forest, agriculture,..
Continuity of Landsat, SPOT
x 2 satellites, 786 km, LTDN 10:30 am
2013 / 2016
Sentinel 3 – Ocean and global land monitoring
Wide-swath ocean color, vegetation, sea/land
surface temperature, altimetry
x 2 satellites, 814 km, LTDN 10:00 am
Sentinel 4 – Geostationary atmospheric
Atmospheric composition monitoring, transboundary pollution
Sentinel 5 – Low-orbit atmospheric
Atmospheric composition monitoring
(S5 Precursor launch in 2014)
2013 / 2017
2019
2020+
2.3 Mission Concept Performance
Parameters
•
The second element of the study will involve the translation of the science requirements
into a satellite mission concept
•
The endpoint of our mission concept work will include specifications for parameters such
as:Mass
Volume
Power
Duty cycle
Data storage requirements
Data downlink requirements
Satellite/sensor orientation during operations
Required pointing accuracy and stability
Thermal control
Radiation shielding
Environmental limits (e.g. Vibration, RF interference, etc.)
Meta-data requirements (e.g. time inputs from GPS)
To get to this point we will need to answer questions relating to system
capacity and operations, as well as defining information products
2.4 Operational Issues
•
Potential areas for discussion include:– Mission/experiment lifetime
• Duration of overlap with Sentinel mission
– Orbit type and orbit maintenance
• Relative position with respect to Sentinel mission
• Relative ground trace with respect to Sentinel mission
• Relative time of coverage with respect to Sentinel mission
– Satellite/experiment orientation during operations
• Pointing relative to Sentinel mission
– Duty cycle relative to Sentinel mission
• Proportion of time spent in “cooperative” modes
– Information required to permit effective convoy operations
• Sentinel orbit data accuracy
• Sentinel mode of operation
• Sentinel station-keeping cycle
• Etc.
2.5 Definitions of Constellation and
Formation Flying
Constellation example:
RapidEye
Formation flying
example: Tandem-X