This thesis addresses a recurring challenge in life science conducted aboard the International Space Station (ISS): despite decades of successful biological research in orbit, many mission teams still encounter and are limited by the same issues and bottlenecks. This is due to the practical knowledge being scattered across publications and inaccessible internal mission documentation, as well as because scientists and engineers often work from different assumptions about constraints and requirements. This thesis therefore aims to bridge this gap by distilling actionable insights and practical recommendations from past ISS experiments, specifically those executed in ESA’s KUBIK and Biolab, and by showing how these insights can directly support the design of a new experiment. The first part of the thesis defines the context ‘around' life science experiments by outlying the space environment relevant to biological payloads. These environmental factors include microgravity and its variability, altered fluid and gas behaviour, ionising radiation sources and shielding effects, and launch/re-entry loads. Next to this, the typical ESA experiment life-cycle, from ‘Announcement of Opportunity' to post-flight reporting, is explained.


To highlight the scientific diversity and the variety of technical challenges, this thesis reviews previously conducted life science experiments in space. The considered experiments are grouped into broad categories: mammalian cells, microorganisms, microscopic animals, and plants. The review performed shows that different biological systems come with distinct technical and scientific requirements, such as growth conditions, handling sensitivities, and analysis needs. Yet, across categories, similar constraints/limitations are found to cause inherent difficulties of conducting life science experiments beyond Earth. In general, limited crew time and availability in orbit pushes experiments towards automation, while limited onboard analytical capability means that detailed analyses are often performed post-flight. Moreover, limited flight opportunities and the added complexity of accounting for space-specific environmental factors contribute to longer preparation timelines. Next to this, it is shown that the space environment can influence the flown biological samples directly and/or indirectly via factors such as: changes in surrounding fluid and gas transport, temperature differences throughout the mission, and pre-flight stresses.

The life science experiments discussed in this thesis are not performed on astronauts themselves, but are instead carried out on biological samples that are packaged into dedicated experiment units/cartridges and operated inside specialised ISS research facilities. These specialised ISS facilities are able to provide controlled conditions and data/power interfaces. Within the scope of this work, several ISS biology-relevant facilities are introduced. These include two of the platforms that ESA has conducted most of their life science research on: KUBIK and Biolab.


Building on this foundation, the second part of the thesis focuses on identifying and presenting factors ‘within' the mission that most strongly shape the success of the experiment. Through both literature research and direct discussions with scientists and engineers at ESA, as well as outside of ESA, fifteen key experiment ‘Design Drivers' are identified. These design drivers are important factors that influence the development and implementation of life science experiments in space, and in a way drive the design of both the mission and the experiment as a whole. Together, these drivers are meant to inform payload design across the full mission flow: from the moment the samples and hardware are brought to the launch site, all the way to when the samples are returned to the science team for analysis. The defined design drivers not only cover parameters that can be chosen by the science team to meet their research objectives, but also include factors that are constrained by mission architecture, safety standards, and operational limitations.

The design drivers introduced within this thesis are the following:
- Sample under Study
- Cleaning and Sterilisation
- Upload Conditions
- Time
- Temperature
- Number of Samples
- Sensors
- Reagents and Fixatives
- Gas Requirements
- Fluid Handling
- Toxicity Constraints
- Biocompatibility
- Mechanisms
- Data Requirements
- Sample Return


For each design driver, the thesis provides a general overview of what role the topic plays in the design and execution of a life science mission. Next to this, actionable insights and practical recommendations are given based on the internal and public documentation of past KUBIK or Biolab experiments. The insights presented highlight the diverse set of problems that teams in the past have dealt with, and emphasises key recurring lessons such as: testing biological and hardware limits under representative (including off-nominal) scenarios, explicitly defining tolerances for time/temperature constraints, designing for microgravity-specific fluid/gas behaviour, and aligning interpretations of requirements across teams to prevent avoidable late-stage changes.



Finally, this thesis demonstrates how the created design-driver-based guidelines can be applied directly to a future mission by considering a relevant case study: the University of Twente Organ-on-a-Chip (OoC) experiment proposal planned to be flown to the ISS. The experiment plans to study the effects of chronic space radiation on human tissue constructs. OoC technology is introduced as a miniaturised microfluidic approach to grow human cells in a controlled environment. This way, the technology is being used for drug research and studying effects on three-dimensional tissues. Through outlining how the University of Twente currently performs these experiments in the lab, and how similar approaches are envisioned for space, insights are given into how the Twente team is designing the space experiment.

By mapping the general design drivers to the proposal of the University of Twente, this thesis highlights where the experiment proposal already anticipates known constraints, and where lessons form past experiments could positively inform the design of the upcoming mission. Emphasising, for example, the need to explicitly test sample robustness under anticipated upload conditions (such as limited power, uncertain stowage, and potential launch delays), to ensure sterilisation and material compatibility across teams working on the mission, to consider different sampling strategies, and to define telemetry and data needs early if real-time monitoring or parallel ground references are envisioned. In this way, the University of Twente mission is used as a practical demonstration that the general recommendations defined in this thesis can inform design choices and planning decisions early on to meaningfully influence mission development.

Overall, the thesis demonstrates how using ESA’s accumulated mission experience can help reduce repeated mistakes, improve communication and shared understanding between scientists and engineers, and support more realistic experiment proposals and implementations. This ultimately strengthens how missions are designed, executed and interpreted, increasing the likelihood of successful future life science experiments in space.

This work presents a kinetic Monte Carlo model to simulate noble gas retention in amorphous solid H2₂O–CO2₂ ice mixtures under varying thermal conditions. Calibrated with experimental temperature-programmed desorption data and temperature–density relations, the model enables long-term simulations in small (~150 nm) ice grains. It shows efficient noble gas retention at ≤30 K, with significant loss near 40 K. Krypton fractionation occurs mainly in ices formed at these warmer temperatures. Using protosolar gas abundances, the model reproduces the noble gas composition measured in comet 67P/Churyumov–Gerasimenko. Results suggest the comet’s bulk formed near 40 K, while its icy grains may trace back to colder (~10 K) presolar reservoirs, preserving signatures of both local and interstellar environments.

Many interplanetary missions with the goal of finding extraterrestrial life have been conducted in the past and more are planned for the future. However, a key gap remains: no long-duration mission has yet explored the clouds of Venus, despite this environment being a promising location to search for signs of life.