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Rensselaer Polytechnic Institute — Ring-Sheared Drop (RSD)

Last updated: Session 79, 2026-04-07

Summary

The Ring-Sheared Drop is a 4-FO-project, 8-year arc (2015–2023) that developed a containerless biochemical reactor through iterative parabolic flight testing, leading to ISS deployment in July 2019. The RSD is now an ISS National Lab facility in the Microgravity Science Glovebox (MSG), supporting research on amyloid diseases (Alzheimer's, Parkinson's) and pharmaceutical bioprocessing. This is one of FO's clearest "parabolic flight → ISS facility" transitions.

FO Projects (4)

ID Title Period TRL Role
91350 Droplet Pinning in Microgravity Testing 2015-04 → 2017-08 4→5 First RSD parabolic flights; design parameter determination
94137 Protein-Drop Pinning in Microgravity 2017-02 → 2019-02 5→6 Continued parameter testing; protein interface studies
106625 Adapting RSD as a Bioreactor 2019-01 → 2021-12 4→6 Bioreactor adaptation (separate application from amyloid)
106698 Fluid Dispensing Tube Performance (D-tube) 2020-02 → 2023-02 4→5 MSFC-led; droplet delivery engineering for ISS RSD

Total FO arc: 8 years, 4 projects, TRL 4→6

Key People

  • Amir H. Hirsa — PI (RPI). All 3 Hirsa-led FO projects. Professor of Mechanical, Aerospace, and Nuclear Engineering
  • Joe A. Adam — Research Scientist (RPI). University Payload Director of the RSD module. 2025 ISSRDC presenter
  • Sridhar Gorti — PI on [106698] (MSFC). Engineering development for ISS flight experiment
  • James Young — Co-I on bioreactor project [106625]
  • Richard Bonocora — Co-I on bioreactor project [106625]

Technology

Concept: A containerless biochemical reactor that uses surface tension to contain a centimeter-scale liquid drop in microgravity. Mixing is achieved by rotating a ring at the equator, creating shear flow through surface viscosity — no container walls needed. This eliminates wall effects that contaminate Earth-based experiments.

Why microgravity: On Earth, buoyancy-driven convection disrupts the delicate interfacial flows being studied. Only in microgravity can researchers isolate surface-tension-driven phenomena at centimeter scales.

Two application tracks: 1. Amyloid research (original): Study formation of amyloid fibrils at fluid interfaces — relevant to Alzheimer's, Parkinson's, type 2 diabetes, and prion diseases. Human insulin used as model protein 2. Bioreactor ([106625]): Adapting RSD as a space-based bioreactor with advantages over membrane-based designs: scalable, no fouling, efficient gas exchange, energy-efficient mixing, low weight

FO→ISS Transition

The FO parabolic flights were explicitly designed to develop and validate RSD hardware for ISS deployment:

FO [91350] (2015-2017): First parabolic flights, design parameters for ISS LMM
    ↓
FO [94137] (2017-2019): Continued testing, protein interface validation
    ↓
ISS Deployment: July 2019 (amyloid study in MSG)
    ↓
FO [106625] (2019-2021): Parallel bioreactor adaptation (separate use case)
    ↓
FO [106698] (2020-2023): MSFC engineering for D-tube delivery to ISS
    ↓
ISS Campaigns: Amyloid study + IBP (Interfacial Bioprocessing of Pharmaceuticals)
    ↓
2025 ISSRDC: Joe Adam presents "Surface Science in Microgravity"

Downstream Impact

Category Details Confidence
ISS facility RSD deployed July 2019; now ISS National Lab facility in MSG Confirmed
ISS campaign: Amyloid Insulin amyloidogenesis studies in microgravity Confirmed
ISS campaign: IBP Interfacial Bioprocessing of Pharmaceuticals Confirmed
Bioreactor [106625] adapted RSD for pharmaceutical/bioprocessing Confirmed
Continuing ISS science 2025 ISSRDC presentation; facility still operational Confirmed
Commercial No commercial outcomes — pure research facility N/A

Publications

  1. "Non-Newtonian Interfacial Modeling of Protein Drops Sheared in Microgravity" — Fluids 2025, 10(3), 58. Computational/modeling paper (Adam, Riley, Lopez, Underhill, Hirsa)
  2. "Amyloidogenesis via interfacial shear in a containerless biochemical reactor aboard the International Space Station" — npj Microgravity 8, 41 (2022). Key ISS results paper
  3. "Simulated microgravity in the ring-sheared drop" — npj Microgravity (2019). Ground-based simulation methods
  4. "Ring-Sheared Drop (RSD): Microgravity Module for Containerless Flow Studies" — Microgravity Science and Technology 29, 81 (2017). Hardware design paper
  5. "Amyloid Fibril Formation in Microgravity via Ring-Sheared Drop" — NASA Task Book entry (linked from TechPort)
  6. PSI data release: PSI-160 (RSD-IBP-I), DOI: 10.60555/smat-bb74 (June 2025)

Financial Tracking

No USASpending search needed — RPI is an academic institution receiving NASA grants. The 4 FO projects represent ~$1-2M in FO funding (typical for academic FO projects). ISS operations costs are separate (MSFC/ISS program funding).

Archetype

"FO Parabolic → ISS Facility" — FO provided the iterative parabolic flight testing environment that allowed progressive hardware development and validation before ISS deployment. This is the canonical version of the FO→ISS escalation archetype: - Parabolic flights (20-25 seconds of microgravity) → prove concept works - Iterate hardware design through multiple FO campaigns - Deploy proven hardware to ISS for long-duration science - Technology becomes a facility serving multiple investigation campaigns

This mirrors the NJIT EHD pattern (FO→ISS grant) but goes further: RSD became a named ISS National Lab facility, not just a single ISS experiment.

Timeline

Date Event
2015-04 FO [91350] starts: first RSD parabolic flights
2017-02 FO [94137] starts: protein interface validation
2017 Microgravity Sci & Tech hardware paper published
2019-01 FO [106625] starts: bioreactor adaptation
2019-07 RSD module launches to ISS (amyloid study in MSG)
2019 npj Microgravity: simulated microgravity paper
2020-02 FO [106698] starts: D-tube engineering (MSFC)
2022 npj Microgravity: ISS amyloid results paper
2023-02 FO [106698] completed (last FO project)
2023-04 SpX-27 launches RSD hardware update (Teledyne Brown Engineering critical science equipment)
2025-07 2025 ISSRDC: Joe Adam presents "Surface Science in Microgravity — Fluid Geometry in the Ring-Sheared Drop"
2025 PSI data release: IBP-I and AFF campaign data published in NASA Physical Sciences Informatics database
2025 2025 ISS campaign: New multi-geometry rheometry experiments conducted on ISS
2026 Additional RSD data planned for PSI release

Session 51 update — ISS facility still active with new campaigns: - The RSD is still operational on ISS as of 2025 — not just maintaining but conducting new experimental campaigns. Joe Adam presented preliminary findings from a 2025 campaign at the 2025 ISSRDC, including multi-geometry rheometry results that offer "deeper insight into the viscoelastic behavior of proteins under shear." This extends the RSD's operational life to 6+ years on ISS (July 2019 – present). - PSI data release: Experiment data from two RSD campaigns — Interfacial Bioprocessing of Pharmaceuticals (IBP-I) and Amyloid Fibril Formation (AFF) — are now accessible in NASA's Physical Sciences Informatics database. IBP-I studied non-Newtonian interfacial hydrodynamics of bovine serum albumin (BSA) and human serum albumin (HSA) in microgravity. Additional RSD data planned for release in 2026. - The 2025 campaign represents at least the third distinct experimental campaign on the RSD facility (after AFF and IBP-I), confirming the facility's value as a multi-use ISS National Lab asset — exactly the trajectory FO parabolic testing was designed to enable. - Assessment unchanged: This remains one of FO's clearest "parabolic flight → ISS facility" transitions, and the continued active use strengthens the case. The 2025 campaign data and 2026 PSI releases will further demonstrate the FO→ISS return on investment.

Session 79 update — New CRS-32 campaign + PSI dataset + publication: - New ISS campaign launched April 21, 2025 (SpaceX CRS-32): NSF-funded campaign (not NASA — via ISS National Lab/CASIS partnership) with expanded protein set: Immunoglobulin G (IgG), Insulin, and Human Serum Albumin (HSA). This is a significant expansion from IBP-I (BSA and HSA only). Conducted in partnership with Tec-Masters, Inc. (Jim McClellan, facility manager). - NSF funding: $452,847 / 3 years (August 2023 start): Hirsa and Patrick Underhill (CBE, RPI) received NSF grant for "protein association, aggregation, and gelation in systems with high protein concentration in the presence of free surfaces." This underpins the CRS-32 campaign and expanded protein set. - PSI-160 dataset published (June 2025): RSD-IBP-I data now publicly available at DOI: 10.60555/smat-bb74. Adam presented this at the PSI User Group Meeting (May 2025). Additional datasets (AFF + 2025 campaign) planned for 2026 release. - New publication: Adam, Riley, Lopez, Underhill, Hirsa. "Non-Newtonian Interfacial Modeling of Protein Drops Sheared in Microgravity." Fluids 2025, 10(3), 58. DOI: 10.3390/fluids10030058. Computational/modeling paper assessing flow in the RSD. - Multi-geometry rheometry journal paper not yet published — results remain preliminary from ISSRDC September 2025 presentation. - RSD confirmed still operational and accepting new users via ISS National Lab. This is now 7+ years of ISS operations (July 2019 – present) across 4+ experimental campaigns (AFF, IBP-I, 2025 multi-geometry, CRS-32 protein expansion). - Assessment: The NSF co-funding (alongside NASA FO origin) demonstrates that the RSD facility has become a multi-agency ISS asset. The expansion from amyloid-specific studies to general protein biophysics broadens the scientific impact. The FO investment in iterative parabolic flight testing (2015–2023) continues to pay dividends through sustained ISS facility usage.

Cross-References