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Starshade Edge Coatings
ZeCoat founder David Sheikh developed an ultra-black coating of layered thin metal and glass films that traps light in nanoscale cavities; it is extremely thin and durable, roughly 100 times thinner than earlier coatings tested for starshades. In JPL tests on starshade edge prototypes, the coating reduced reflected light by about a factor of 20, enough to help a telescope image exoplanets.
- Reflectance Goal: Avg. R <1.5% and max R <2.4% from 450–850 nm
Publications
Reflectance by Band
| Band | Avg. Reflectance | Max Reflectance |
|---|---|---|
| 400-450 nm | 1.0% | 2.4% |
| 450-500 nm | 0.3% | 0.4% |
| 500-550 nm | 0.7% | 0.9% |
| 550-600 nm | 1.1% | 1.3% |
| 600-650 nm | 1.4% | 1.5% |
| 650-700 nm | 1.5% | 1.5% |
| 700-750 nm | 1.3% | 1.4% |
| 750-800 nm | 1.0% | 1.2% |
| 800-850 nm | 0.7% | 1.0% |
Environmental Durability
| Test | Specification | Description |
|---|---|---|
| Adhesion | MIL-PRF-13830B | Slow-pull, 90-deg |
| Abrasion | MIL-PRF-13830B | Moderate cheesecloth, 50 strokes |
| 24-hr Humidity | MIL-PRF-13830B | 50C/95%/24-hr |
| Thermal Cycle | ZeCoat Modified 13830B B.4.4.4 | +100 C / -85 C |