SpaceX explains how it is reducing the brightness of Starlink satellites.

According to SpaceX, the collaboration allowed it to pinpoint and address the main factors contributing to satellite brightness. In order to make the satellites undetectable to the human eye when they are at their normal operational height, the company is working on this.

Observers on earth may be able to see satellites if they are backlit by the sun at night. Any satellite's visibility, however, is influenced by the materials that were utilised to construct its surfaces.

Since satellites don't produce any light of their own, the brightness comes from sunlight reflecting off their surfaces and down to earth. Specular or diffuse scattering are the two possible types of light scattering.

Specular surfaces are a focus for SpaceX. Similar to a mirror, specular light only reflects at one angle. Diffuse light reflects in numerous directions. The illustration above demonstrates how diffuse and specular light disperse differently.

Not all materials are extremely reflective; some can absorb light or make the light that is reflected appear significantly less bright, according to SpaceX.

There are two ways to see SpaceX's satellites from the ground.

SpaceX created sun visors for the first-generation satellites that prevent sunlight from striking the chassis's bottom side (body of the satellite.) Engineers created materials for their creation that are radio frequency invisible. The laser links that SpaceX uses to extend coverage to far-off parts of the earth were, however, obstructed by the sun visors. The satellites experienced severe drag as a result of the visors. So, SpaceX came to the conclusion that the sun visors weren't a practical long-term fix.

Sun visors were replaced by RF-transparent mirror sheets, which SpaceX created. Most of the sunlight is scattered away from the Earth by the coating. According to SpaceX, it has been enhancing its mirror sheets to reduce light scattering back to earth. It intends to use its next-generation satellites to broadcast an updated version of the movie.

SpaceX stated that their next-generation satellite will increase the Starlink network's capacity and connect more people in more locations.

I'll focus on one of the three cutting-edge brightness approaches that the second-generation satellites will employ: Dielectric Mirror film.

The satellites' undersides will be covered with a second-generation dielectric mirror film by SpaceX. By employing a Bi-Directional Reflectance Distribution Function (BRDF) metric, this version reduces the observed brightness ten times better than the first-generation film.

The chart below illustrates how the BRDF affects visibility.