Note: The presentation of the Community Briefing, as well as the FAQs have been added as an annex to this Announcement of Opportunity. Both annexes (4 & 5) can be found and downloaded at the bottom of the page. 

1. INTRODUCTION

After graduating from ESA’s basic training in April 2024, Marco Sieber has become Switzerland’s second astronaut. A medical doctor, he is now a member of the ESA astronaut corps and currently undergoing advanced training. Marco Sieber will be the first Swiss national to fly a mission to the International Space Station (ISS). Although the date of his first flight has not yet been set, it is expected to take place between 2027 and 2029. The duration and timing of the flight is subject to change, and ESA and the Swiss Delegation reserve the right to manage the results of this Announcement of Opportunity (AO) accordingly. 

During their missions on board the ISS, ESA astronauts can dedicate some resources to experiments proposed by Participating States in ESA’s Human and Robotic Exploration Programme. Preference is given to experiments proposed by the country of origin of the ESA astronaut. In this context, and Switzerland being one of the Participating States in the Programme, there is now a window of opportunity for Switzerland to promote experiments that could be flown on board the ISS during Marco Sieber’s mission.

The ISS with ESA’s Columbus module has been a critical platform for conducting scientific research in microgravity. The ISS has hosted numerous experiments in a wide range of fields, including biology, physics, and materials science. The unique microgravity environment of the ISS allows researchers to study phenomena that are impossible to observe on Earth. Moreover, the location of ISS in Low Earth Orbit and the ability to easily communicate with ground control makes ISS an attractive location for testing new technologies and conducting scientific investigations to advance European space exploration.

In a first step, the Swiss Delegation to ESA, part of the State Secretariat of Education, Research and Innovation SERI, has called upon stakeholders in Switzerland to express their interest in providing potential experiments. Taking into account the outcome of this Call for Interest, the Swiss Delegation and ESA now invite stakeholders from Switzerland to submit proposals in response to this AO.

2. OBJECTIVE OF THE OPPORTUNITY

The objective of this AO is to solicit for proposals from Swiss entities for experiments that could fly to the ISS during the first mission of Marco Sieber. The experiments shall be in line with the Swiss Space Policy as well as ESA’s Explore2040 Strategy. 

The selected proposals will be eligible to receive funding to support the development of hardware or software products that are needed to perform the experiments. The rules of the corresponding ESA Programme that will be used for this support (PRODEX or GSTP) will apply. The Swiss Delegation to ESA has allocated a total budget of 5 Mio. Euro for experiments selected through this AO. Between 5 and 10 experiments are planned to be implemented.

3. APPLICATION PROCESS

Submit your proposal by clicking “Submit Your Idea” and filling in all sections of the submission form and uploading supplementary information where indicated. Check the eligibility conditions and guidelines of the respective ESA Programme (PRODEX or GSTP) before submitting a proposal. Only complete proposals will be considered for evaluation.

You can use the OSIP platform to ask questions as needed, or reach out to the following campaign managers:

• For questions related to Physical Sciences activities, please contact Dr. Brice Saint-Michel (brice.saint-michel@ext.esa.int).
• For questions related to Life Sciences activities, please contact Dr. Nolan Herssens (nolan.herssens@ext.esa.int).
  
  

4. TIMELINE

• Briefing to community and Q&A session: 28 October 2025, 15:00-16:00 CET
• Deadline for submission: 5 January 2026 at 23:59 CET  
• Feedback to proposers: April 2026

4.1 Briefing to Community and Q&A Session

ESA and the Swiss Delegation will jointly organize an online briefing to the community with a Q&A session on 28 October 2025, 15:00 – 16:00 CET. This session aims to present the details of the AO and to address any questions that prospective proposers may have. The briefing is designed to assist interested teams in preparing comprehensive full proposals.

You may register for the community briefing and Q&A session here.

5. GUIDELINES

In your proposal (Annex 1), please consider the following:

1. Experiments can include scientific payloads or technological demonstrator payloads (hardware or software). These must be able to be performed on board the ISS.
   
   
2. Experiments shall be in conformity with the objectives of the Swiss Space Policy and ESA’s Explore2040 Strategy.
   
   
3. Experiments shall aim to promote scientific excellence or state-of-the-art technology demonstrations. This AO is specifically targeting payloads and experiments focused on:
   • the understanding and improvement of human and astronaut health;
   • innovative space life sciences;
   • advancing robotics and the use of virtual reality (VR) in space;
   • understanding planetary processes (granular and fluid physics).
     
     
4. The following restrictions apply:
   • The cumulative mass of all payloads to be uploaded to the ISS cannot be heavier than 15 kg.
   • Proposed experiments that require the installation of hardware outside of the ISS cannot be considered.
     
     
5. The cumulative crew time available will depend on the actual mission duration, which is still to be confirmed. Please clearly indicate the experiment’s requirements in the corresponding section of the proposal template (Annex 1).  
   
   
6. The preparation and implementation of the proposed payloads (hardware and software) and experiments need to be realistically completed within a timeframe of 1-2 years after project kick-off.
   
   
7. Transportation to and from the ISS, on-board resources and crew time will be provided by ESA. ESA experts will support the preparation and integration of the experiment on the ISS, in particular with regard to safety aspects.