Drag the detector line • Space: pause photons • B: best focus

Space Lens Simulator

Pass 07 • long-path bulk-transmission requirement + lab witness gate

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Read it left → right

1Distant source. A star and planet at the far left stand in for an object sending nearly parallel light.

2The lens material bends the rays. They refract once entering and again leaving the sphere.

3The bright region is the useful concentration zone. It is a caustic, not one perfect mathematical point.

4The detector samples the light. Move it near the bright region for the tightest image.

5Observer preview. The small preview window shows a simplified view of what the detector would see.

Material authority

Selected material1000 cSt PDMS-class dimethyl silicone fluid

Why this one: silicone oils at 200, 1000 and 5000 cSt were used to form refractive liquid lenses during published microgravity flight tests. A representative 1000 cSt dimethyl silicone fluid has density ≈970 kg/m³, refractive index ≈1.403 at 25 °C, pour point below −50 °C, and specified volatile matter below 0.5% after 24 h at 150 °C. We use 1000 cSt as a reproducible representative baseline, not as a claimed optimum viscosity.

Scientific boundary: this remains our current liquid engineering candidate for this spherical-lens concept, not a proven astronomical winner. The published PDMS optical study establishes transparency and optical constants in laboratory samples, but it does not validate tens-of-meters astronomical path lengths. Pass 07 therefore calculates the attenuation PDMS would need to achieve and only predicts full-sphere transmission when a real, interface-corrected bulk witness measurement is entered.

2026 update: Fluidic Shaping has now also been demonstrated aboard the ISS with UV-cured centimeter-scale polymer lenses and a 172 mm water lens. That strengthens the in-space manufacturing concept, but it still does not supply the long-path PDMS attenuation measurement needed for this full-sphere design.

Teaching controls

Lens sphere size (schematic) Detector position

Animate photon markers

Show explanation labels

Show observer preview

Physical experiment calculator

Target preset

Sphere diameter (m)

Observation wavelength (nm)

Target diameter (km)

Target distance (ly)

Projected planet-star separation (AU)

Material density

PDMS authority value970 kg/m³

Direct-imaging IWA (λ/D)

The drawn sphere is schematic. “Projected separation” means the sky-plane separation at the time of observation, not automatically the orbital semi-major axis. Diffraction values are ideal lower bounds; biosignature spectroscopy does not require resolving the planetary disk.

Bulk transmission gate

Required aperture-weighted bulk throughput

Lab witness path (m)

Measured bulk transmission (%)

Enter bulk-only transmission after correcting/removing window and interface losses. The extrapolation uses Beer–Lambert attenuation, T = exp(−αL). It assumes homogeneous linear loss and therefore does not model bubbles, particulates, contamination films, radiation damage, wavelength-dependent scattering, or nonlinear degradation.

Scientific model boundary

This is a 2D geometric-optics model of a full spherical refractive element in vacuum. It is not the same geometry as NASA FLUTE’s framed liquid-primary-mirror concept. The observer preview is pedagogical; it is not a diffraction-accurate reconstructed exoplanet image.

Not yet modeled from authoritative telescope-scale measurements: intrinsic PDMS attenuation versus wavelength, radiation aging, contamination, wavefront error, detector noise, photon/SNR exposure time, coronagraph throughput, exozodiacal background, thermal control, rotation/tides, or active shape correction. The witness gate is an extrapolation tool, not a replacement for those measurements.

Material authority references: Luria et al. (npj Microgravity, 2023) formed microgravity refractive lenses using 200, 1000 and 5000 cSt silicone oils; Roychowdhury et al. (Surface Science Spectra, 2018) measured liquid-PDMS optical properties from 191–1688 nm; Luria et al. (npj Microgravity, 2026) demonstrated Fluidic Shaping aboard the ISS; representative 1000 cSt dimethyl-silicone product data give density 0.970 g/mL, n≈1.403, pour point <−50 °C and volatile matter <0.5% after 24 h at 150 °C. Long-path astronomical attenuation is still not guessed.