Advisory Committee for Earth Observation. The Advisory Committee for Earth Observation (ACEO) is the senior advisory body to the European Space Agency's (ESA's) Director of Earth Observation (EO) Programmes. The Advisory Committee acts as the representative of the Director General of the European Space Agency on all matters concerning Earth observation-based Earth Sciences in the Earth Observation Programmes of ESA.

Role 
ACEO is the main interpreter of the views and needs of the European scientific community as regards access to space experimentation and EO data exploitation in the Earth science community.  Its main tasks are to advise and/or make recommendations on:

 the needs of the scientific community for remote observations of Earth;
 scientific activities during the development, implementation and exploitation of the approved projects of ESA's Earth Observation programmes
 the formulation and updating of medium and long-term Earth Observation Science Strategy in Europe in regard to the interests of the scientific community;
 the priorities of the scientific community in the selection (and extension) and formulation of future Earth Observation missions, and the associated Calls for Proposals for new mission ideas;
 the science aspects in relation to the evolution of operational Earth Observation missions in terms of the space segment (planning, succession, Long-Term Scenario), the operational services and the impact of operational missions on EO Science;
 the contribution of ESA EO missions to address major societal issues;
 ESA's EO system architect role, considering EO missions developed at National level;
 the impact of NewSpace on ESA EO programmes; 
 the scientific studies and activities required to lay the foundations for future missions; 
 the selection of new scientific projects.

The ACEO has the highest-level advisory capacity, through the Director of Earth Observation Programmes (D/EOP), for matters to be treated at the level of the Programme Board for Earth Observation (PB-EO), which may also request advice on particular issues of a scientific nature.

Membership 
ACEO is composed of invited members who are senior European scientific experts and ex-officio representatives of relevant stakeholder bodies, and is managed by the ACEO Secretariat in the Earth and Mission Science Division. ACEO members are selected ESA Executive to achieve diversity and balance in scientific expertise across the relevant Earth science disciplines, from within ESA Member States, and Canada, Latvia, Lithuania, Slovenia, or Slovakia.

Membership appointments are for a period of three years with the possibility to extend to a maximum of five years. The tenure of the chair is for three years, independent of previous normal membership, with the possibility of a one-year extension.

The Chair of the PB-EO is invited, ex officio, to attend the meetings of the ACEO. Furthermore, representatives of other ESA Directorates’ Science Advisory Committees may be invited to attend.

Representatives of scientific or professional organisations with a stake in Earth Observation (e.g. European Space Sciences Committee (ESSC) of the European Science Foundation, whose expertise may be required by ACEO to properly fulfil its functions can also be invited, ex-officio and Ad Personam, to attend the meetings.

Operating Procedure 
The Committee meets at dates and places jointly agreed between the chair and the Director of Earth Observation Programmes.

ACEO provides advice and/or makes recommendations on the items referred to it by the Director of Earth Observation Programmes. Members of the Committee may however raise issues they wish to discuss.

The Chair of the ACEO reports on the committee's recommendations at the meetings of the PB-EO. The Chair of PB-EO can make a request to the Director of Earth Observation Programmes for ACEO to carry out specific actions in the framework of its mandate.

The ACEO Secretariat is managed by ESA's Earth and Mission Science Division.

Past Chairpersons 

 2023–present:  Prof. R. Forsberg
 2020-2023:       Dr. F. Rabier
 2018-2021:       Prof. M. Visbeck
 2014-2018:       Prof. W. Mauser
 2010-2014:       Prof. A. O'Neill
 2007-2010:       Prof. J. Johannessen
 2003-2007:       Prof. H. Graßl
 1999-2003:       Prof. L. Bengtsson
 1996-1999:       Prof. G. Mégie

History 
The ACEO was established in 2018  to replace the former Earth Science Advisory Committee (ESAC) as the senior advisory body to the Director of Earth Observation.

The former Earth Science Advisory Committee had been in place operating as the main science advisory body from the inception of the ESA Living Planet Programme in 1996 until 2018. Prior to that the Earth Observation Advisory Committee (EOAC), created in 1981, had been the senior scientific advisory body to the Application Satellites Directorate on programmes, projects, studies and application of this field.

References 

European Space Agency
Satellite imaging sensors
Satellite imagery
Space agencies
European space programmes
European Space Agency programmes