Mission

Why thrombosis, why microgravity

Spaceflight makes dangerous blood clots more likely, and nobody has ever checked whether the treatment for them still works up there.

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? Right now, nobody knows — because thrombolysis has never been tested in microgravity. CLOT-LESS exists to produce that first measurement.

This is the first study to investigate thrombolysis kinetics in vitro within a reduced-gravity environment.

Test Equipment Data Package, Rev B

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

Objectives

Four questions this flight has to answer

Each objective traces from a science question down to the instrument that answers it, with the measurable criteria that decide whether it was met.

  • 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

  • Evaluate flow-dependent differences

    At identical, pump-controlled infusion rates in 0 g and 1 g, determine whether microgravity alters clot lysis time by changing how long the drug actually resides at the clot interface.

    Holding the pump rate identical in both gravity conditions isolates the variable of interest. If lysis still differs, the cause is not how fast fluid is being driven through — it is how gravity changes the local behaviour of that fluid at the clot face, and therefore how long the drug is in contact with it.

    Three measures are computed for each run: time to a 25% and 50% pressure drop (T₂₅ and T₅₀), the area under the ΔP(t) curve, and a clot lysis rate constant normalised against the no-drug controls.

    Flow setpoints
    2.5 and 5.0 mL/min
    Flow stability
    ±5%
    Primary endpoints
    T₂₅, T₅₀ and AUC
    Resolution
    ≥5% ΔP in 20 s

  • Validate system reliability

    Confirm that the integrated fluidic, sensing and logging system behaves consistently across repeated parabolas — because an unreliable instrument cannot answer the first two questions.

    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

Seven phases from procurement through to knowledge translation.

  1. Phase 0

    In progress

    Material procurement

    All mechanical and electrical components, IV tubing and fluids secured. Porcine blood procurement remains in progress.

  2. Phase 1

    In progress

    Ground development and prototyping

    Mechanical assembly under way on the baseplate. Pumps, pinch valves, relay modules, the Raspberry Pi, IP65 enclosures and the camera mount are installed; microchannels, tubing, pulsation dampeners and the wiring harness are in progress. Control software — GUI, pump and valve control, pressure sensing, temperature control and flow logging — is largely complete.

  3. Phase 2

    Upcoming

    Optimization, calibration and testing

    Sensor calibration, flow-rate verification against the setpoints, thermal characterisation of the 37 °C fluid heating loop, and end-to-end system testing ahead of ground studies.

  4. Phase 3

    Upcoming

    Ground studies

    Full experimental runs at 1 g, producing the matched baseline dataset every microgravity measurement is compared against.

  5. Phase 4

    Upcoming

    Parabolic flight campaign

    Twelve parabolas across two flight days aboard the research aircraft, each delivering roughly twenty seconds of microgravity.

  6. Phase 5

    Upcoming

    Data analysis and reporting

    Reduction of the pressure and imaging data, computation of T₂₅, T₅₀ and lysis rate constants, and preparation of the manuscript.

  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

Objective four is not decoration. A result that stays inside the team does not advance the field.

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 once flight data has been compiled.

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.