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Internal Research Fellow (PostDoc) in NGGM Project GNC Performance and Simulation

Job Requisition ID: 20277

Date Posted: 2 February 2026

Closing Date: 23 February 2026 23:59 CET/CEST

Publication: External Only

Type of Appointment : Internal Research Fellow

Directorate: Earth Observation Programmes

Workplace:

Noordwijk, NL

Location

ESTEC, Noordwijk, Netherlands

Our team and mission

Gravity is a well-established observable, and has been integral to Earth observation from space since the beginning, as shown, for example, by the measurement of Earth's oblateness in 1958. Measuring the gravity field reveals Earth's state of mass distribution and its dynamics. It also provides the geoid as a reference for sea level, global ocean circulation and height systems. In addition, the temporal variations of gravity and the geoid help to measure mass exchange processes in the Earth system. Knowledge about the time-varying gravity field contributes to all Earth observation science applications, including hydrology, cryosphere, solid Earth, oceanography, atmosphere, geodesy and climate research.

The measurement principle of the Next Generation Gravity Mission (NGGM) will rely on the high-accuracy measurement of the variation in inter-satellite distance due to the time-varying gravity field via a laser tracking instrument and accelerometers to measure the non-gravitational accelerations acting on each satellite, which, in the data processing, will be separated from those caused by the gravity signal. NGGM will make it possible to measure and monitor Earth's time-varying gravity field and its trends at sub-weekly, monthly to seasonal, and long-term timescales in regions up to 70 North/South at a high resolution in time (down to 5 days) and space (down to 100 km).

NGGM is set to launch in 2032.

You will become an integral part of the NGGM Project System Section within the broader ESA NGGM Project Team, which consists of highly specialised engineers from various engineering disciplines.

The Section currently has nine members who work together closely and take pride in being part of an ambitious and motivated team. You will have the opportunity to contribute to a real project implementation, and your work will provide essential inputs for one of the most challenging and complex ESA Earth observation missions in the near future.

Specifically, your research will provide critical insight for NGGM performance assessment and predictions.

You are encouraged to visit the ESA website: https://www.esa.int/

Field(s) of activity/research for the traineeship

The Next Generation Gravity Mission consists of a pair of satellites providing two types of measurement to map Earth's gravity field. The first measurement is the variation of inter-satellite distance, measured by a laser interferometer. The second is the non-gravitational acceleration at the centre of mass of each satellite, obtained from ultra-sensitive accelerometers on board each platform. This translates into tight control requirements of the fine relative pointing accuracy between the two satellites and the linear and angular accelerations sensed by the accelerometers. These objectives are achieved via a Drag-Free Attitude and Orbit Control System (DFAOCS) to provide each spacecraft with a drag-free environment and fine pointing capabilities. The control performance of the DFAOCS must then be assessed by means of a high-fidelity end-to-end simulator. The current design of the NGGM DFAOCS could benefit from the latest advances in control theory and the use of a robust control framework in which system design, parametric sensitivity and worse-case analysis can be rigorously performed using state of-the-art tools.

The goal of the proposed research is to explore the use of advanced control design and verification techniques for the design of the Drag-Free Attitude and Orbit Control System of the Next Generation Gravity Mission. To achieve this goal, four different objectives must be fulfilled:

• Set up a high-fidelity end-to-end simulator for the Drag-Free Attitude and Orbit Control System.
• Set up a linear modelling framework for frequency domain design and verification using linear fractional representations.
• Prototype and implement advanced control methodologies to meet the DFAOCS performance and stability objectives.
• Demonstrate the end-to-end stability and performance capabilities of the DFAOCS with parametric sensitivity and worst-case analysis.

To fulfil the above objectives, the proposed programme of work for the Research Fellowship is the following:

• Year 1: Detailed problem formulation, setup of the simulation environment and models, and preliminary control methodology.
  • Development of a high-fidelity simulation environment capturing the relevant dynamics, DFAOCS sensors and actuators and including all relevant payload elements used in the science-mode control loop;
  • From the high-fidelity simulator, perform the derivation of adequate analysis and synthesis models that capture model uncertainties using linear fractional representations;
  • Model identification, validation and uncertainty quantification;
  • Set up the performance and stability analysis frameworks to verify the DFAOCS performance and stability, using a combination of well-established and robust analysis tools (e.g. mu-analysis) and Monte-Carlo time domain non-linear simulations, including variations in all the uncertainties expected in the modelling of the systems involved in the DFAOCS;
  • Propose a baseline robust controller synthesis for drag compensation and fine pointing.

• Year 2: Detailed trade-off and implementation of selected control methodologies, advanced controller synthesis, performance and stability assessment.
  • Trade-off, prototyping and selection of advanced DFAOCS control methodologies: minimum set to be explored: model predictive control schemes, embedded-model control, data-driven approaches and robust controller synthesis;
  • Implementation of the selected control methodologies in the high-fidelity end-to-end DFAOCS simulator;
  • Model-in-the-loop performance and stability verification of the proposed design and control methodologies;
  • Design iterations.

Technical competencies

Knowledge relevant to the field of research

Research/publication record

Ability to conduct research autonomously

Breadth of exposure coming from past and/or current research/activities

Ability to gather and share relevant information

General interest in space and space research

Behavioural competencies

Result Orientation

Operational Efficiency

Fostering Cooperation

Relationship Management

Continuous Improvement

Forward Thinking

Education

You should have recently completed, or be close to completion of a PhD in a related technical or scientific discipline. Preference will be given to applications submitted by candidates within five years of receiving their PhD. In particular for this position, the following is required:

PhD in control engineering, preferably applied to space systems AOCS/GNC.

Additional requirements

In addition to your CV and your motivation letter, please prepare a research proposal of no more than 5 pages. This proposal should be uploaded to the "additional documents" field of the "application information" section.

You should also have good interpersonal and communication skills and should be able to work in a multi-cultural environment, both independently and as part of a team. Your motivation, overall professional perspective and career goals will also be explored during the later stages of the selection process.

Diversity, Equity and Inclusiveness

ESA is an equal opportunity employer, committed to achieving diversity within the workforce and creating an inclusive working environment. We therefore welcome applications from all qualified candidates irrespective of gender, sexual orientation, ethnicity, religious beliefs, age, disability or other characteristics.

At the Agency we value diversity, and we welcome people with disabilities. Whenever possible, we seek to accommodate individuals with disabilities by providing the necessary support at the workplace. The Human Resources Department can also provide assistance during the recruitment process. If you would like to discuss this further, please contact us via email at .

Applicants must be eligible to access information, technology, and hardware which is subject to European or US export control and sanctions regulations.

During the recruitment process, the Agency may request applicants to undergo selection tests. Additionally, successful candidates will need to undergo basic screening before appointment, which will be conducted by an external background screening service, in compliance with the European Space Agency's security procedures.

The information published on ESA's careers website regarding working conditions is correct at the time of publication. It is not intended to be exhaustive and may not address all questions you would have.

The working languages of the Agency are English and French. A good knowledge of one of these is required. Knowledge of another Member State language would be an asset.