These equations check scale and internal consistency. They do not establish flight safety or medical benefit.
For water density rho, covered area A, and average thickness t:
m = rho A t and sigma = rho t.
Using rho = 1000 kg/m^3:
| Thickness | Areal density | Water mass over 10 m² |
|---|---|---|
| 0.05 m | 50 kg/m² (5 g/cm²) | 500 kg |
| 0.10 m | 100 kg/m² (10 g/cm²) | 1,000 kg |
| 0.20 m | 200 kg/m² (20 g/cm²) | 2,000 kg |
The table is a mass calculation, not a dose-reduction prediction.
A cylindrical water volume of radius 1.5 m and length 3.0 m contains
pi r^2 L = 21.2 m^3, or about 21,200 kg of water. Dedicated launch mass at
that scale is not credible for an early demonstrator. AquaShield therefore uses
existing mission water where possible, a smaller elastic cell, and partial
filling rather than assuming a permanently flooded room.
A first-order drag estimate is
F = 0.5 rho Cd Ap v^2,
where Cd is drag coefficient, Ap projected area, and v relative water
speed. For Cd=1, Ap=0.10 m²:
| Water speed | Estimated force |
|---|---|
| 0.25 m/s | 3.1 N |
| 0.50 m/s | 12.5 N |
| 1.00 m/s | 50.0 N |
Actual limb loading is unsteady and posture-dependent; calibrated force sensors must replace this estimate in testing.
Ideal hydraulic power is P_h = delta_p Q; electrical input is
P_e = delta_p Q / eta. At 40 kPa, 0.010 m³/s, and 60% efficiency, estimated
electrical power is 667 W before thermal-control overhead.
Drain time is T = V/Q. Draining 0.50 m³ at 0.025 m³/s takes 20 seconds in the
ideal volume-balance calculation. Real plumbing losses, deformation, trapped
water, valve time, and loss of power must be tested.