Mission

Why thrombosis, why microgravity

CLOT-LESS investigated clot dissolution in reduced gravity during the CAN-RGX flight campaign.

The problem

Thrombosis is the formation of a blood clot inside a vessel. It is driven by Virchow's triad: altered blood flow, injury to the vessel lining, and a blood chemistry that clots too readily. Change any one of the three and risk goes up.

Spaceflight changes the first. Without gravity pulling blood toward the feet, fluid redistributes toward the head, venous blood velocity changes, and flow in some vessels has been observed to reverse outright. Those are precisely the conditions that raise the risk of a clinically significant clot — deep vein thrombosis, and from there pulmonary embolism or cerebral sinus thrombosis.

Why it matters more the further you go

In low Earth orbit, a serious medical event can be met with ground expertise in real time and, in the worst case, a return. On a mission to Mars neither is available. Communication delays run to tens of minutes each way, the pharmacy is whatever was packed, and the crew has to act alone.

That makes one question unavoidable: when an astronaut is given a clot-dissolving drug in microgravity, does it work the way it does on Earth? CLOT-LESS was designed to investigate this question. The team has now completed the CAN-RGX flight campaign, bringing the experimental platform from the bench into reduced gravity.

This study investigated thrombolysis kinetics in vitro within a reduced-gravity environment.

Programme
CAN-RGX 2025–26
Agent
Tenecteplase (TNKase)
Model
Porcine blood clots, in vitro
Biosafety
Level 1 / Risk Group 1
Flight days
Two

Project goals

  • Develop a testable platform for zero-g research

    Develop an experimental platform for testing thrombolysis and other hematologic research questions in zero gravity, with ground testing to support repeatable experiments.

    Bring fluid delivery, pressure sensing, imaging and data acquisition together in an experimental platform that can be tested on the ground and operated during reduced-gravity flight.

    Thrombolysis is the first application. The broader goal is to support future hematologic research in zero gravity by adapting the platform to new experimental questions and validating each setup before flight.

  • Quantify microgravity effects on thrombolysis

    Measure the differential pressure change across a clot-containing microchannel during tenecteplase perfusion, in microgravity and at 1 g, over matched twenty-second analysis windows.

    A clot lodged in a channel raises the pressure needed to push fluid through it. As the clot dissolves, that resistance falls. Tracking differential pressure — ΔP — across the channel therefore gives a continuous, quantitative readout of lysis in progress, without having to see inside the vessel.

    The comparison is made against control-normalised kinetics within the twenty-second microgravity window of each parabola, matched against an identical window on the ground.

    Pressure range
    ±100 mbar (±1.45 psi)
    Detection threshold
    ≥10% ΔP in 20 s
    Sampling rate
    ≥50 Hz
    Absolute accuracy
    ≤ ±0.03 psi

  • Validate system reliability

    Confirm that the integrated fluidic, sensing and logging system behaves consistently across repeated parabolas — to support repeatable hematologic experiments in reduced gravity.

    Each parabola subjects the payload to roughly 2 g on the pull-up, then near-zero g, then 2 g again on the pull-out. Pumps, valves, sensors and the logging chain all have to behave identically on the twelfth repetition as on the first.

    Reproducibility of the control channels is the test: if signals from the saline loops drift across parabolas, any difference measured in the drug channels cannot be attributed to gravity with confidence.

    Parabolas
    12 across two flight days
    Coefficient of variation
    ≤5% on control loops
    Data loss
    <5% per flight day
    Measurement latency
    <0.2 s end to end

  • Deliver scholarly and educational impact

    Translate the findings into peer-reviewed output and into classrooms — because a result that stays inside the team does not advance the field or the next generation working in it.

    An abstract has been accepted to the 77th International Astronautical Congress in Türkiye, covering the experimental design and the case for the research. Results will follow in future papers once flight data has been compiled.

    Three age-appropriate STEM modules are in development for elementary and high school audiences, aimed at both the science and at showing students that space research is something university students can actually do.

    Conference abstract
    Accepted — IAC 77
    Manuscript
    ≥1 in preparation
    STEM modules
    3 in development
    Target sessions
    6–8 classroom visits

Programme

Where the project stands

The flight campaign is complete. Post-flight work focuses on reviewing the data and sharing the findings.

  1. Phase 0

    Complete

    Material procurement

    Materials were secured for the flight campaign.

  2. Phase 1

    Complete

    Ground development and prototyping

    The experimental platform was assembled and prepared for ground testing and flight.

  3. Phase 2

    Complete

    Optimization, calibration and testing

    Pre-flight system checks and preparation were completed ahead of the campaign.

  4. Phase 3

    Complete

    Ground studies

    Ground testing supported preparation of the experimental platform for flight.

  5. Phase 4

    Complete

    Parabolic flight campaign

    The team completed the CAN-RGX parabolic flight campaign.

  6. Phase 5

    In progress

    Data analysis and reporting

    Post-flight work focuses on reviewing the pressure and imaging data and preparing reports.

  7. Phase 6

    Upcoming

    Outreach and knowledge translation

    Delivery of the three STEM modules to elementary and high school classes, and presentation of results at university and at the International Astronautical Congress.

Outreach

Beyond the flight

Sharing the research through publications, presentations and classroom activities.

Accepted

77th International Astronautical Congress

Thrombolytic Pharmacodynamics in Microgravity: Implications for Autonomous Medical Care in Deep Space — an oral presentation of the experimental design and the case for the research. Results will follow in future papers after analysis of the flight data.

Paper
IAC-26,A1,3,9,x113307
Session
6 October 2026, 16:20 · Hall 7
Location
Türkiye
In development

Three STEM modules

Built for elementary (Grade 7) and high school (Grades 10–12) audiences, targeting six to eight classroom sessions.

  • Zero Gravity and the Human Body What weightlessness does to bone, muscle, balance and circulation.
  • Medicine in Microgravity Why drug delivery, wound healing, surgery and imaging all get harder without gravity.
  • Our CAN-RGX Journey What a student-led research project actually looks like — including the parts that go wrong.