Announcement of Opportunity for
Guest Investigators in the Proba-3 mission

Through this Announcement of Opportunity (AO), the European Space Agency (ESA) solicits applications by scientists to augment the scientific return of the ASPIICS instrument of the Proba-3 mission and aims to appoint up to five Guest Investigators (GIs) from ESA Member States for a duration of one year.

Proba-3 is an in-orbit demonstrator of precise formation flying techniques and technologies under the responsibility of ESA’s Directorate of Technical and Quality Management (D/TEC). It is a technology demonstration mission in the PROBA (PRoject for On-Board Autonomy) programme. The Proba-3 mission consists of two spacecraft that were launched on 5 December 2024 into a highly elliptical orbit around the Earth (600×60,530 km, 19.6 hour orbital period, inclination of 59°). For up to 6 hours in each orbit, the two spacecraft maintain a precise formation. One spacecraft carries a coronagraph telescope, while the other carries an external occulter, producing a long baseline solar coronagraph. The primary scientific payload of Proba-3 is the solar coronagraph ASPIICS.

The Proba-3 mission was launched on 5 December 2024. The two satellites flew jointly from launch until their separation on 14 January 2025. Demonstration of the precision formation flying was achieved in early May 2025 and the first artifical solar eclipse was created in early June 2025. The duration of the nominal science operations is two years, currently scheduled until November 2026.

Proposal Documentation

An invitation from the ESA Director of Science to respond to this Announcement of Opportunity can be found in the right-hand menu.

Full details of the appointment requirements and conditions, the required contents and format of the proposal, and the evaluation criteria are given in the Announcement of Opportunity document, available to download from the right-hand menu.

Proposal Submission form

Proposals must be submitted using the online form – see link to the form below.

An acknowledgement of receipt will be sent to the applicant at the email address provided, upon successful submission of the proposal.

Late submissions will not be considered. The submission deadline will be implemented strictly and proposers are invited to submit their proposal well in advance of the deadline.

Schedule

The schedule for this AO is given in the table below:

Privacy notice for this Announcement of Opportunity

Any individual responding to this Announcement of Opportunity (AO) must provide some personal data as part of the submission process. Protection of personal data is of great importance to ESA. This privacy notice describes important aspects of how the data submitted for this AO will be treated. Please read the privacy notice carefully.

By ticking the checkboxes presented to you when submitting your application, you confirm that you agree with the collection and further processing of your personal data. You will not be able to submit your application without providing this consent as it is required to further process your application.

Contact

Last updated: 19 December 2025

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