Stem-cell organoids

Who it is for

• Pharmaceutical and biotech teams that use iPSC-derived organoids in drug discovery for neurodegenerative disease (Parkinson's, multiple sclerosis, Alzheimer's)
• Academic stem-cell and neuroscience labs, and the disease foundations that fund them
• Regenerative-medicine developers working on iPSC-derived cardiomyocytes and other cell products
• Space agencies and human-spaceflight programs that study risks to the central nervous system on long missions
• Organoid and iPSC tool companies that need flight validation of their culture media, cassettes and assays

What earlier flights found

How LELP-1 runs it

Sample. iPSC-derived 3-D organoids made in the customer's lab. The reference case is cortical or dopaminergic neural organoids, with or without matched microglia, as on the 2019 ISS flight. Cardiac progenitor spheres are a second option. One organoid goes in each well, with matched patient and control lines spread across the cassette. Container. LELP-1 large-bay 24-well sealed culture cassette with about 1 mL of medium per well (the heritage flight used 1 mL per sealed cryovial). It connects to the bay fluidics, with reservoirs for medium, 4% paraformaldehyde (PFA) fixative, PBS storage buffer, RNA stabilizer and waste. The bay provides BSL-2 triple containment. Launch. Live organoids in sealed wells with HEPES-buffered medium, loaded late, with the bay held at 37 C and powered through ascent. On the 2019 ISS flight the organoids were shipped at 4 C and flew live in a 37 C incubator. Option for cardiac spheres: launch cryopreserved at -80 C in the passive cassette and thaw automatically in orbit. On the 2020 heritage flight, the thaw was done by hand on board, so an automated thaw has no flight heritage. Light and gas. No light is needed except short LED exposures for imaging. There is no CO2 supply. Wells use HEPES-buffered medium (heritage: DMEM/F-12 with 15 mM HEPES) and a sealed air headspace, with no gas exchange during flight. On the 2019 flight, organoids in sealed 1 mL cryovials showed no signs of hypoxia after 30 days.

1. day -3

   The customer lab finishes the organoids (aggregation, regional differentiation, and microglia added where used). The batch is split evenly between the flight cassette and the ground-control cassette.

2. day -2

   Organoids are shipped at 4 C to the integration site. The 2019 heritage team shipped to Kennedy Space Center at 4 C.

3. day -1

   One organoid is loaded into each well with 1 mL of HEPES-buffered medium. The cassette is sealed and installed in the bay at a 37 C setpoint, and the bay stays powered from here on. Spare organoids from the batch are fixed on the ground as the launch baseline.

4. day 0

   RUPAK launch with the bay held at 37 C. Logging of acceleration, temperature and radiation dose starts.

5. day 1

   In-orbit checkout: seal and pressure check, then a brightfield image of every well as the in-orbit baseline.

6. day 2

   Daily brightfield imaging of all live wells for organoid size and shape, timed outside robotic-arm moves. Fluorescence images are taken if the customer uses reporter lines.

7. day 3

   Early time point: in 4 wells, the medium is pumped to waste and replaced with RNA stabilizer. The 2020 cardiac flight fixed samples in RNAProtect at day 3.

8. day 7

   Optional half-medium exchange (0.5 mL) in the live wells from the medium reservoir. Skip it to match the no-exchange heritage protocol. The arm carries the bay to the central 40x microscope for high-resolution images of 2 to 4 wells.

9. day 12

   Last full imaging round of all live wells.

10. day 13

    End of culture. In 8 wells the medium is replaced with 4% PFA for histology. In 6 wells it is replaced with RNA stabilizer. 6 wells stay live in their own medium for return, and that medium carries the secreted proteins.

11. day 13.2

    After about 4 hours of fixation, the PFA in the 8 histology wells is pumped to waste and replaced with PBS storage buffer to avoid over-fixation during the trip home.

12. day 13.5

    The bay setpoint is ramped from 37 C to 4 C and held. Imaging and pumping stop during the ramp so power stays under the peak limit.

13. day 14

    Deorbit and splashdown, with the bay held at 4 C on battery. The cassette goes to the customer's courier about 20 minutes after splashdown and reaches the lab at 4 C within 1 to 2 days.

The payload module, in CAD

Every item in the module sheet, drawn and packed into the large bay deck by deck. The back face mates with the bay: blind-mate connector, and a cold wall against the bay's thermoelectric block. The front face carries Dexter-L's grapple fixture, and the fluid lines run down a channel just behind it. What you load before launch is marked blue in the configurator's payload guide.

CAD generated by cad/build_modules.py (CadQuery, OpenCascade kernel) from the catalog's module items: concept geometry, not a released design. Standard parts keep their real formats; the rest are sized from their catalog mass. The front panel and grapple fixture are left off in the 3-D view and are in the STEP.

• The XY stage travels 96.5 x 57.9 mm, so every one of the 24 wells reaches the objective; with the stage the imaging stack is 232 x 151 mm, which sets the module's depth budget.
• Reagent volumes the catalog does not state are split evenly from 75 % of the reservoir item's mass. The waste bag holds the spent medium and washes; fixatives and stabilisers stay in the wells and come home.
• Fluid pack: 4 reagent bags in 2 layers (167 x 122 x 46 mm), every port on a front edge.
• The waste bag lies under the reagent bags and fills the room they free: they hold 701 mL, it needs 351 mL.
• The catalog gives 0.90 kg for structure and containment; as an aluminium box that is a 0.34 mm skin on 0.40 kg of posts and shelves. Thin: the bay rails have to carry the launch loads, or the module needs more structure mass.
• The grapple fixture stands 26 mm proud of the front panel, into the bay opening; everything else is inside the bay envelope.

Ground control

An identical flight-spare large-bay module and 24-well cassette, filled from the same organoid batch on the same day and kept at 37 C in the customer's or the integrator's lab. It runs the same fluidics timeline: RNA stabilization on day 3, an optional exchange on day 7, PFA fixation and RNA stabilization on day 13, the swap from PFA to PBS, and the cool-down to 4 C. It runs a few hours behind the flight so it can replay the flight bay's temperature log, and it goes through the same 4 C hold and courier trip. Launch-baseline organoids fixed on day -1 show the starting state. The standard bay has no in-orbit 1 g centrifuge, so the only microgravity control is on the ground. Launch vibration, radiation and 1 g are not matched; the dosimeter and accelerometer logs are used to account for them.

Coming home

The organoids are fixed or RNA-stabilized in orbit on day 13, before deorbit, so re-entry and the 1 g trip home do not change the end-point. Fixed organoids are moved from PFA to PBS after about 4 hours to avoid over-fixation. Live-return wells are cooled to 4 C, the temperature the heritage team used to ship live organoids before launch. The 72-hour window from preservation to the lab is our planning value: about 1 day in orbit, about 20 minutes to handover, then 1 to 2 days by courier. In the 2019 heritage flight, the CubeLab was opened six days after undocking.

Limits of this flight

• LELP-1 runs at most 14 days. The neural-organoid heritage flights lasted about 30 days, so changes seen after a month may be smaller or missing at 14 days. The 3-day cardiac data suggest that early gene changes can be measured.
• The standard bay has no in-orbit 1 g centrifuge. Microgravity effects cannot be separated from launch, radiation and hardware effects as cleanly as with the centrifuge control in the ISS MVP.
• Mature brain organoids launch live, not frozen, which needs a powered late load and a short pad timeline. We did not find a flight-proven method to cryopreserve whole mature neural organoids and thaw them automatically. The cryopreserved option has flight heritage only for cardiac progenitor spheres, and that thaw was done by hand on the ISS.
• There is no crew on board. Bubbles, a blocked line or a leaking well cannot be fixed by hand, so the protocol depends on the automated fluidics working the first time.
• The bay has no CO2 supply. The culture relies on HEPES buffering in sealed wells, which limits how long and how dense the culture can be before pH and oxygen drift. Without the optional sensors, pH and oxygen are not measured in flight.
• With 24 wells and one organoid per well, groups are small once lines, microglia conditions and time points are split. The heritage authors said their protein data lacked statistical power.
• Live-return organoids spend up to about 3 days at 4 C after the flight. Cold storage changes gene expression, so only organoids fixed or RNA-stabilized in orbit give a clean flight end-point.
• Electrophysiology (multi-electrode arrays) and single-cell sequencing happen only after return. The bay cannot record neural activity in flight.
• Each robotic-arm move raises the g level to about 1e-4 to 1e-3 g, so imaging at the central microscope slightly disturbs the microgravity condition.
• The BOARDS (Muotri) results quoted here come from ISS National Lab reports. We did not find a peer-reviewed flight paper for them.