Sentinel Convoy: Synergetic Observation by MissionsFlying 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 iceb) landc) atmosphere

SSTL, the University of Leicester and Astrium Ltd areundertaking the second of these studies:

Sentinel Convoy: Synergetic Observation by MissionsFlying 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 small-class 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

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

FOCUS OF THE WORKSHOP

PRELIMINARY DISCUSSION

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

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

1.1 Priority Science Areas

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

• NASA A-train– Combining data sets from instruments gives

better understanding of parameters affecting climate change

• PREMIER (infrared limb sounder & mm-wave 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

2.1 Examples of Synergistic Missions

2013 / 2015

Sentinel 1 – SAR imagingAll weather, day/night applications, interferometryx 2 satellites, 693 km, Dawn dusk orbit

2013 / 2016

Sentinel 2 – Multi-spectral imagingLand applications: urban, forest, agriculture,.. Continuity of Landsat, SPOTx 2 satellites, 786 km, LTDN 10:30 am

2013 / 2017

Sentinel 3 – Ocean and global land monitoringWide-swath ocean color, vegetation, sea/land surface temperature, altimetryx 2 satellites, 814 km, LTDN 10:00 am

2019

Sentinel 4 – Geostationary atmosphericAtmospheric composition monitoring, trans-boundary pollution

2020+

Sentinel 5 – Low-orbit atmosphericAtmospheric composition monitoring(S5 Precursor launch in 2014)

2.2 Sentinel Mission Summary

• 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

2.3 Mission Concept Performance Parameters

• 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.

2.4 Operational Issues

2.5 Definitions of Constellation and Formation Flying

Constellation example:

RapidEye

Formation flying example: Tandem-X