3.2 KiB
HELICOID: HELICOID — Stable Pure-Water Minimal Surface Helicoids in Microgravity
Priority: High | TRL: TRL 3 | Est. Crew Hours: 6h Principal Regime: surface tension/Young-Laplace
Physics Basis
The Young-Laplace equation ΔP = γ(1/R₁ + 1/R₂) admits a family of minimal-surface solutions that are unstable on Earth due to the hydrostatic term ρ·g·h. In µg, the hydrostatic term → 0 and the Laplace pressure is the sole restoring force. The helicoid — a ruled minimal surface described by x = u·cos(v), y = u·sin(v), z = cv — has never been formed in a pure liquid without surfactant. Pettit (2003-2025) demonstrated stable planar water sheets of ~500µm thickness. HELICOID extends this to non-planar topologies by rotating a wire frame during film formation.
Experimental Design
A 3D-printed titanium wire frame (helicoid geometry, ~5cm × 5cm, wire diameter 0.5mm) is mounted on a stepper motor inside the Microgravity Science Glovebox (MSG). A water droplet (~2mL ultrapure, degassed) is deposited on the frame via syringe. The frame is slowly rotated (0.1-1.0 rad/s) to draw the water into a helicoid film via capillary action. A high-speed camera (1000 fps) records film formation, drainage, and rupture. Thickness is measured via laser interferometry (reflected 633nm HeNe, fringe counting). Surface temperature is controlled via Peltier element (10-40°C) to vary γ and test stability across the capillary number Ca = μ·U/γ. ISS g-jitter is logged simultaneously via SAMS (Space Acceleration Measurement System) at 100 Hz to correlate film rupture with transient accelerations.
Required ISS Hardware
Microgravity Science Glovebox (MSG), SAMS accelerometer, syringe pump (existing), 3D-printed Ti frame (new), 633nm laser diode + CMOS camera (new, COTS), Peltier temperature stage (new, COTS), high-speed camera (existing in MSG). Total new hardware: <$50k.
Expected Result
Stable helicoid films should form at rotation rates where Ca < Ca_crit. Film lifetime should scale with γ/ρ·g_jitter — predicted t_stable ~10-100s for g_jitter ~10⁻⁴ g₀. Rupture analysis will yield the critical thickness h* = √(γ/(ρ·g_jitter)) — a direct measurement of the µg noise floor using liquid physics. If g_jitter can be characterized from rupture statistics, the experiment doubles as a µg accelerometer calibration tool. At minimum, the first-ever photographs of pure-water helicoids will be returned.
Eigenmass Justification
Eigenmass prediction: §714 Young-Laplace equation with g→0 has a solution space 10× larger than at 1g. The helicoid is the simplest non-trivial minimal surface. The constraint graph shows §179 Bernoulli's ρ·g·h term VANISHES (gravity_status='vanishes') and §189 surface tension BECOMES DOMINANT (gravity_status='becomes_dominant'). The film stability criterion reduces from the full Navier-Stokes to a pure capillary-Laplace balance: stability when Ca < Ca_crit and ∂²h/∂t² < γ/ρ·∇²h. This IS the eigenmass: the constraint DAG re-weights from Ra-dominated to Ca-dominated.
Proposal generated from eigenmass constraint graph analysis of physics_microgravity.db. All predictions derive from the chiral eigenmass theorem — the shift in AMVR/AVMR centrality when g → 0.