Free Astronomy Magazine September-October 2026

9 ASTRO PUBLISHING eral thousand, similar to the number of stars seen with the naked eye in good conditions. Other planned satellite constellations such as E- Space’s Cinnamon and China’s CTC-1 and 2 would add hundreds of thou- sands more satellites into orbit, com- pounding the problem. Reflect Orbital, a US start-up, aims to launch a constellation of very large mirror-like satellites to provide sunlight at night, with reflected beams that span at least five kilome- tres on Earth’s surface. They intend to start with a prototype satellite in orbit this year and plan to increase their satellite population to 50,000 by 2035. These satellites would be the brightest ever in orbit, with damaging consequences for dark skies on Earth. Hainaut’s calculations show that the full constellation would fill the night sky with hun- dreds of very brightly visible satel- lites. Seen from within a reflected beam, the satellite delivering sun- light would appear four times brighter than the full Moon. Even if no satellite points its beam direct- ly at an observer, each would be as bright as the planet Venus, the ‘morning star’. From a light-polluted city, like Munich, Germany, these hundreds of satellites would be the only ‘stars’ visible in the night sky. These proposals, combined with others considered in the study, would dramatically brighten the night sky, hindering humankind’s ability to observe faint cosmic tar- SEPTEMBER-OCTOBER 2026 SpaceX plans to send one million more satellites into orbit, for space- based data centres, which would sig- nificantly alter the appearance of the sky. The new study shows that, for a large fraction of each night, hundreds of satellites would be visi- ble and, at certain times, up to sev- T his image shows satellites cross- ing the night sky above the northern Atacama Desert in Chile, over a period of just one hour. It is a stack of a time-lapse video taken on 15 October 2025 about two hours after sunset. A few streaks are caused by planes, and can be easily identified by their blinking- coloured lights, but most trails are due to satellites. In the foreground we see the dome of ESO’s Extreme- ly Large Telescope (ELT), the world’s largest optical/infrared telescope, currently under construction atop Cerro Armazones. Behind it we see the lasers of ESO’s Very Large Tele- scope (VLT) at Paranal Observatory, 22 km away from the ELT. [F. Kam- phues, ESO/M. Kornmesser]