Note: As of December 2025, Evaluation and selection phase has been delayed until Q1/Q2 2026 (Please refer to new dates in Section 3. 'Application Process', below). 

As of 11 September 2025, this Announcement of Opportunity has been updated to (i) reflect the integration of  optional the ESA’s HRE Exploration Biobank as part of the campaign setup, (ii) clarify the eligibility criteria by specifying that proposal teams must not include members of the associated study facility responsible for implementing the core IBRIS protocol, and (iii) specify that all components of the proposal submission must be provided in English.

The Q&A virtual meeting material and link to the recording has been added (18 Sep 2025). 

1. INTRODUCTION

ESA's Exploration Science Programme: Advancing Knowledge, Inspiring Innovation

The European Space Agency's Exploration Science Programme, a cornerstone of its Explore2040 strategy, invites scientists, researchers, and innovators to join us in pushing the boundaries of human knowledge and technological capabilities. Our programme uniquely balances exploration-focused science, essential for enabling future human missions beyond Earth, with exploration-enabled science that leverages our capabilities for groundbreaking research across disciplines.

We support a wide spectrum of scientific investigations, from understanding the impact of spaceflight on astronaut health and developing countermeasures and health monitoring tools for long-duration spaceflight, to exploring fundamental physics in microgravity, prospecting for lunar resources, and searching for signs of past life on Mars. The ESA Exploration Science Programme offers a platform to turn your scientific vision into reality.

To enable this breadth of research, we provide access to a diverse and evolving suite of platforms. These include ground-based analogues of spaceflight conditions, as well as the International Space Station, upcoming commercial low Earth orbit stations, and a range of lunar and deep space exploration initiatives, each offering unique environments and challenges.

Guided by core European values of collaboration, scientific excellence, and responsible exploration, we seek proposals that not only advance our understanding of the universe but also contribute to solving global challenges here on Earth. Our programme emphasises open science, international cooperation, and the inspiration of future generations.

Through this Announcement of Opportunity (AO), we invite proposals for research activities to be implemented within the “AO-2025-IBRIS” campaign. We welcome studies that contribute to advancing our understanding of integrated physiological responses to relevant space stressors.  

Background on Scientific Directions & Areas of Focus

Proposals submitted under this Announcement of Opportunity (AO) are encouraged to align with ESA’s Terrae Novae exploration programme, Europe’s flagship initiative for human exploration of the Solar System. Guided by the long-term vision of the Explore2040 strategy, Terrae Novae seeks to ensure a sustained European presence in low Earth orbit (LEO), enable human exploration of the Moon, and prepare for future missions to Mars. This scientific agenda is strongly informed by the goals of human health, performance, and sustainability across increasingly distant and demanding environments.

In this context, the IBRIS campaign supports these strategic goals by advancing the understanding of human physiological adaptation to simulated microgravity conditions. By combining a short dry immersion (DI) phase offering fast-onset physiological effects with a longer head-down tilt bed rest (HDT) period suitable for extended observation and intervention, IBRIS provides a powerful analogue for investigating health risks relevant to short- and long-duration space exploration missions.

Proposals are particularly encouraged in the following areas, which are key to ESA’s exploration science strategy:

• Crew Health & Performance: Investigating early and progressive markers of physiological deconditioning across the DI and HDT phases, developing and validating targeted countermeasures (e.g., exercise, compression, nutritional, or technological interventions), and improving physiological monitoring strategies to enhance crew health, safety, and performance during and after exposure to simulated microgravity.
    
• Habitation: Testing and validating medical support systems, autonomous health monitoring tools, and compact diagnostic or therapeutic technologies relevant for future space habitats; assessing how human physiological changes under simulated spaceflight conditions may impact interaction with life support systems, mobility aids, and other habitat-enabling infrastructure.

These strategic directions are further supported by ESA’s Exploration Science programme, as reflected in the SciSpacE white papers  and the papers published in "The Future of Science of Space Exploration: a European view", which outline a broad range of life and physical science disciplines relevant to exploration. These resources highlight research areas that address fundamental scientific questions whilst also enabling exploration and contributing to terrestrial applications.

In addition, ESA's ExPeRT (Exploration Preparation, Research and Technology) area coordinates the development of studies and technologies for future missions to low Earth orbit, the Moon, and Mars. This preparatory work is essential for Europe's participation in upcoming international exploration opportunities.

Applicants are encouraged to align their proposals with one or more of the strategic objectives outlined above. Clearly identifying which scientific directions or programme priorities are addressed, and how the proposed research contributes to advancing ESA’s exploration goals, will help ensure the relevance and impact of the submission.

2. DESCRIPTION OF THIS OPPORTUNITY

Rationale and general overview

Building on the success of the VIVALDI study series, particularly the recent VIVALDI III campaign, which combined a 10-day dry immersion phase with a parallel 10-day head-down tilt bed rest study, ESA is launching the next step in ground-based analogue research. Dry immersion has emerged as a promising and complementary analogue to bed rest, effectively simulating key physiological effects of spaceflight such as gravitational unloading, fluid shifts, and musculoskeletal deconditioning.

Building on this momentum, the Immersion and Bed Rest Integrated Study (IBRIS) aims to introduce a novel experimental paradigm combining a short period of dry immersion (DI) followed by a longer period of head-down tilt bed rest (HDT). This integrated approach is designed to facilitate the evaluation of countermeasures and physiological responses relevant to short-duration and longer-duration space missions.

There is a clear need for a fast and adaptable experimental model capable of rapidly assessing countermeasures, nutritional strategies, and environmental conditions using relevant early markers of physiological adaptation. Dry immersion offers a rapid-onset simulation of the effects of microgravity through buoyancy-induced gravitational unloading, triggering immediate physiological responses such as central hypervolemia and reduced postural muscle tone. These changes closely mimic the neuromuscular and sensorimotor adaptations observed in spaceflight. In contrast, the HDT enables longer-duration studies and is particularly suited for a careful evaluating of the efficacy of countermeasures over time.

By combining the two models, IBRIS leverages the complementary strengths of DI and HDT to provide a flexible, scalable, and time-efficient platform for investigating physiological adaptation and selected countermeasure effectiveness.

NOTE: The implementation of this study is subject to formal funding confirmation by the ESA Ministerial Council, scheduled for November 2025. Upon Ministerial Council outcome and budget availability, preparatory activities will commence following proposal selection and approval.

Protocol Structure

The IBRIS protocol is designed to allow multiple experimental groups to be tested in parallel. It integrates both ground-based analogues and consists of four main phases: Baseline Data Collection (BDC), Dry Immersion (DI), Head-Down Tilt Bed Rest (HDT), Recovery (R) and Follow-Up phase. The duration of each phase may be adjusted during the study preparation phase to optimize scientific output and operational feasibility.

• Phase I, Baseline Data Collection (BDC):
  • Duration: 7 days with uninterrupted presence at the facility.
  • Execution of baseline standard measurements, and dedicated measurements from science teams from selected proposals.
• Phase II, Dry Immersion (DI):
  • Duration of 5 days.
  • Objective to induce rapid deconditioning through gravitational unloading, triggering acute physiological responses.
  • No countermeasures will be implemented during this phase.
• Phase III, Head-Down Tilt Bed Rest (HDT):
  • Duration of 16 days.
  • Continuous 6-degree HDT without a pillow.
  • Implementation of dedicated countermeasure (see below).
• Phase IV, Recovery phase (R):
  • Duration: 7 days with uninterrupted presence at the facility.
  • Execution of standard study measurements, and measurements from science teams/proposals.
• Phase V, Follow-Up (R):
  • The study foresees the inclusion of standalone follow-up measurements at R+14 and R+28.

Please note that this call is not soliciting (exercise) countermeasure proposals but focuses on fundamental and applied research into physiological responses and mechanisms using the IBRIS model. If any (exercise) countermeasures shall be implemented, these will be restricted to those proposed by the ESA Space Medicine Team (HRE-HM) as indicated below.

Experimental Design

• Groups:
  • Normo-caloric: control group, caloric intake at 1.2 times the resting metabolic rate, with an additional 10% to account for diet-induced thermogenesis. Protein consumption should stay constant at 1.2 grams per kilogram body mass per day.
  • Hypocaloric: daily caloric intake reduced by 20-25%, protein consumption should stay constant at 1.2 grams per kilogram body mass per day.
  • Hypocaloric + exercise countermeasure

• Exercise Countermeasure during HDT: Flywheel exercise, rowing exercise.
• Number of participants: 10 participants per group.
• Parallel Design:
  • Groups run in parallel without crossover to avoid washout periods and reduce dropout risk.
  • Groups will be matched on sex, height, fat mass and VO2max as much as possible.
• Sex Balance:
  • Equal representation of male and female participants is prioritized (aiming for 50/50 split).
• Age Range:
  • Subjects between the ages of 25 and 45 will be included.

To ensure scientific coherence and operational feasibility, submitted proposals should align with the overarching IBRIS protocol structure. This includes fitting within the defined study phases (BDC/DI/HDT/R (Recovery and Follow-up)), adhering to the proposed timelines, and integrating into the experimental group configurations. Investigators are encouraged to tailor their protocols to leverage the unique characteristics of each study phase, while remaining compatible with the parallel group design and sample size considerations. In doing so, they should refer to the standard measurement overview and timing outlined in Annex 1, and are advised to indicate both their preferred and acceptable time windows for each measurement to facilitate scheduling flexibility. Proposals that demonstrate adaptability to this shared structure will be prioritized for integration into the IBRIS campaign. 

Furthermore, the implementation of the core IBRIS protocol, including all study phases and standard measurements, will take place at a dedicated study facility designated by ESA. This facility will provide the operational framework and infrastructure for the campaign, within which selected science teams will integrate their investigations. 

Scientific Objectives

ESA encourages proposals to leverage the Immersion and Bed Rest Integrated Study (IBRIS) campaign as a novel and accelerated analogue for studying the physiological impacts of spaceflight and evaluating targeted countermeasures.

The overarching aim is to generate actionable insights that improve crew health and performance during future long-duration exploration missions, whilst simultaneously delivering benefits for health and medicine on Earth.

The following targeted scientific objectives may serve as guidance for proposal development.

a. Physiological Deconditioning and Recovery

• Identify early markers of cardiovascular, musculoskeletal, and sensorimotor decline during dry immersion (DI) and head-down tilt bed rest (HDT).
• Characterize the progression of these changes across the combined DI + HDT protocol.

b. Countermeasure Efficacy

• Evaluate and test the effectiveness of selected exercise countermeasures (i.e., flywheel exercise or rowing exercise) in mitigating deconditioning.

c. Sensorimotor and Neuromuscular Function

• Assess the impact of unloading on balance, posture, motor control, and proprioception.
• Investigate targeted interventions to preserve or restore sensorimotor function.

d. Sex-Based Differences

• Examine sex-specific physiological adaptations and countermeasure responses. Tailor countermeasures to ensure efficacy between the sexes.

e. Environmental and Nutritional Influences

• Explore how inactivity, fluid shifts, sensory inputs, and nutritional status (i.e., hypocaloric diet) affect adaptation and/or recovery.

f. Validation and Demonstration of Health Monitoring Technologies

• Validate and demonstrate point-of-care diagnostics, wearable biosensors, imaging technologies, and non-invasive tools for tracking physiological changes and countermeasure outcomes.
• Test novel technologies for real-time vital sign monitoring, autonomous health assessment, and decision-making support under spaceflight-relevant operational constraints.
• Evaluate the integration, performance, and readiness of closed-loop systems for real-time feedback and adaptive countermeasure guidance.
• Assess the usability, accuracy, and maturity of medical AI tools for autonomous triage, diagnostics, and therapeutic recommendations.

g. Translational and Modelling Approaches

• Replicate physiological changes in stem cell or iPSC-derived biomedical models.
• Investigate whether cardiovascular, musculoskeletal, and sensorimotor markers from DI and HDT are reflected in these models.
• Assess sex-based differences in biomedical models.
• Utilise microgravity simulation platforms (e.g., Clinostats, RPMs) to support mechanistic studies.

Note: Depending on the scientific complement and the level of interest in exploration-focused science, non-exploration focused/enabled research not tackling the above priorities but addressing groundbreaking community questions may also be accommodated, subject to available capacity and fit with the overall scientific complement.

Standard Study Measurements and Data Access

A core set of standardized DI and HDT measurements will be collected across all participants in the IBRIS campaign. A preliminary overview of these measurements is provided in Annex 1.

Please not that the final list of standard measurements will be confirmed during the study preparation phase and may be subject to change based on feasibility assessments, potential conflicts between measurements, and resource constraints. To support collaborative research and maximize scientific return, ESA will establish data-sharing agreements that allow science teams access to these datasets.

Applicants must clearly indicate in their proposals which specific standard datasets they intend to use and how these will support their research objectives. This will help ensure appropriate data provisioning and alignment with the study’s operational planning.

3. APPLICATION PROCESS

All components of the proposal submission must be provided in English, including the content of the online submission form and any uploaded attachments or supporting documents. 

Kindly submit your completed proposal template (Annex 2) by clinking on the “Submit Your Idea” button below. Complete all sections of the submission form as per guidelines outlined in the call, respective attachments and in the provided proposal template, and upload any additional information as required.  ESA will organise a Q&A virtual meeting to present the details of the call and the associated facility, and to address any questions from prospective proposers. This session is intended to support interested teams in preparing strong and well-informed proposals.

Whilst preparing their proposals, applicants are required to contact their respective national space agencies to inform them of their intended submission. This step is essential to explore potential national funding procedures, timelines, and likelihood of support, and to identify alternative funding sources if necessary.  (refer to "Who can apply?" section, below).

Note: Any additional measurements proposed by the science teams (e.g., MRI, muscle biopsies) that fall outside the standard protocol (i.e., bedrest standard and/or dry immersion measures) will not be covered by ESA and thus must be fully funded by the proposing teams themselves. Furthermore, the inclusion of such measures is not guaranteed and will depend on both operational feasibility and resource availability within the study framework.

If you have any further technical questions during submission, feel free to contact the Campaign Manager.

Privacy Notice

Please ensure that all team members complete and sign the Privacy Consent Form (Annex 3) and include them as part of the proposal submission.

Schedule

The schedule for this Announcement of Opportunity is as follows (please note dates are tentative):

Launch of Announcement of Opportunity                                       09/07/2025

Letter of Intent (LoI) submission deadline                                       20/08/2025

Q&A virtual meeting:                                                                       12/09/2025 at 14:00-15:00 CEST

Link to Meeting:

Microsoft Teams Need help? 
Join the meeting now 
Meeting ID: 312 836 536 680 3 
Passcode: KR6tP2U3 

Link to Q&A Submission Form (deadline 08/09, 12:00 CEST): https://forms.office.com/e/PjrHBMJ03V

Q&A meeting material: Presentation (link! or see Attachments), Video Recording (link! - request access via link if needed).

Submission deadline for Full proposals:                                          12/10/2025 at 23.59 CEST

Notification of Selection due:                                                               Not before Mid 05/2026

Preparation of the study:                                                                      01/06/2026 - 30/11/2026 (Tentative)

Investigator Working Group meeting #1                                              Q3 2026

Investigator Working Group meeting #2                                              Q1 2027 (Tentative)

Implementation:                                                                                    Not Earlier Than Q2 2027

Letter of Intent (Annex 4): 

Science teams interested to apply are invited to submit a Letter of Intent (LoI), using the template that you can find in the attachments. You can submit the LoI via the submission form and you can then later supplement/update your idea with the full proposal requirements. This LoI allows us to give feedback to your project if needed. Please note that a LoI is non-binding and not mandatory. Even if you submit a LoI, you can deviate from it for your full proposal and even if you do not submit a LoI, you are still eligible to submit a full proposal. 

Please note that you can use also the OSIP platform to ask any questions in case of uncertainties. 

4. IMPLEMENTATION OF THE SELECTED PROPOSALS

Following a positive peer and technical review, the scientific coordinator of each selected proposal will be notified that the project has advanced to the definition phase and will be added to a pool of candidate activities. It is the responsibility of the scientific coordinator to inform the rest of the science team of this preliminary selection. Upon selection, the science team will be required to provide experiment-specific documentation and will be required to support coordination meetings to define the scientific requirements and prepare for experiment implementation. Please note that selection for definition phase does not guarantee implementation. Feasibility issues may arise during the definition process.

Once the notification of selected proposals has been communicated, each selected science team will be required to prepare an Activity Requirements Document (ARD), outlining all aspects of the proposed experiment. Following the completion of the experiment, a Data Blank Book (DBB) must be completed to document all acquired datasets for archiving purposes. Additionally, ethical approval and medical board clearance must be obtained before any experiment can proceed to implementation.

This Announcement of Opportunity provides access solely to the Dry Immersion and Head-Down Tilt Bed Rest study and its volunteer cohort. Science teams are responsible for securing funding to cover all associated costs, including personnel time, travel expenses, required equipment, and any on-site, experiment-specific measurements (e.g., MRI, muscle biopsies, etc), shipment of physical samples from the study facility to the science team's premises or laboratories, as well as other operational needs to support their activities. Applicants are therefore expected to initiate their funding requests in parallel with the preparation of their proposal (see “Who can apply?” section below).

Given logistical and facility considerations, the study may be implemented across two separate campaigns, each comprising the same phases: BDC, Dry Immersion (DI), Head-Down Tilt Bed Rest (HDT), Recovery, and Follow-Up. Due to facility constraints, participants in each campaign will be organized into sub-groups based on the availability of immersion baths and bed rest beds. As a result, data collection will be staggered, and scientific teams conducting complex or time-sensitive measurements should anticipate multiple travel periods to align with the different participant sub-groups. We strongly recommend that applicants reflect this in their funding requests, ensuring adequate resources are allocated for travel and associated logistics.

ESA reserves the right to select only specific components of a submitted proposal if those elements are deemed to have high scientific merit. In such cases, the applicant will be given the option to accept or decline the partial selection. If two or more proposals address similar scientific questions or methodologies, ESA may request that the respective science teams consolidate aspects of their projects into a single collaborative effort.

NOTE: The implementation of this study is subject to formal funding confirmation by the ESA Ministerial Council, scheduled for November 2025. Upon Ministerial Council outcome and budget availability, preparatory activities will commence following proposal selection and approval.

Contribution to ESA’s HRE Exploration Biobank  

ESA is establishing an HRE Exploration Biobank to enable future research opportunities by preserving biological samples collected during exploration-related studies. As part of the campaign setup, science teams submitting proposals for the IBRIS campaign will be asked to formally acknowledge their awareness of the biobank initiative where participation involves making residual sample fractions from their approved investigations available for long-term storage in the ESA HRE Exploration Biobank. The detailed process, including documentation requirements, ethical considerations, and applicable standards, will be communicated at a later stage during the study preparation phase. Formal agreements, where applicable, will also be addressed at that time. Please note that any contribution of residual samples will require participant consent and inclusion in the relevant ethical approvals prior to implementation. 

5. DATA RIGHTS AND DATA MANAGEMENT RESPONSIBILITIES

Please ensure you are familiar with the data rights, data ownership, and the data management responsibilities applicable to the datasets a selected science team will acquire as part of the campaign as outlined in the ESA HRE Data Policy (see Annex 5).

Publications and Acknowledgement

Any publication of the results generated in the context of this research announcement of opportunity shall be provided to ESA and must acknowledge the sponsorship of the study by the European Space Agency. Additionally, the title of the publication shall include the name of the corresponding campaign, i.e., IBRIS.

Example/Reference:

“This research was carried out within the framework of the IBRIS study and was supported by the European Space Agency (ESA). The authors acknowledge the sponsorship of the European Space Agency under the associated Announcement of Opportunity (AO-2025-IBRIS), with reference number [XXXXX].”

Support of Education and Outreach

The activities covered in this research announcement provide an opportunity for the European Space Agency to engage the public and offer opportunities for education and outreach. Science Teams are encouraged to promote and communicate their investigations to a wide audience (general public, colleagues, involvement of students, social media) and to support the European Space Agency in the event of organized press conferences, social media events, educational activities, publications, etc.