A peer-reviewed study led by the European Southern Observatory (ESO) and published in Astronomy & Astrophysics calculates that more than 1.7 million satellites proposed by commercial and state actors would raise night-sky background brightness to levels that cause “devastating consequences” for ground-based optical astronomy. The research, the first to quantify the cumulative photometric impact of mega-constellations, finds that the total number of satellites in low Earth orbit must not exceed roughly 100,000 and that each must remain fainter than naked-eye visibility (magnitude 7) to keep observatories viable. Currently, about 14,000 active satellites are aloft, dominated by SpaceX’s Starlink network; the company alone has filed for up to one million additional spacecraft for orbital data centres.

Satellite trails already streak across images from ESO’s Very Large Telescope in Chile, causing field-of-view losses of up to 28% during twilight hours. The study singles out Reflect Orbital, a U.S. start-up planning 50,000 large mirror-like satellites to beam sunlight to Earth at night, as a particular threat: even outside a direct beam, each would appear as bright as Venus, transforming pristine dark-sky sites into suburban-grade skies. Wide-field survey telescopes, such as the Vera C. Rubin Observatory, are especially vulnerable because a single bright trail can saturate detectors and render entire exposures unusable.

While ground-based astronomy confronts this orbital crowding, space-based instruments continue to deliver results unhindered by atmospheric or photometric interference. In a separate study published in Nature, researchers using the James Webb Space Telescope (JWST) performed transmission spectroscopy on WD 1856 b, a Jupiter-sized planet orbiting a white dwarf 80 light-years away. The single-planet sample revealed an atmosphere rich in methane and aerosols, with a temperature of 390–412 kelvin—more than double the expected 160 kelvin. The excess heat, the authors conclude, is residual energy from a migration event that occurred billions of years after the host star’s death, supporting the hypothesis that gas giants can survive the red-giant phase and later spiral inward through gravitational perturbations in multi-star systems.

Viewed from Washington, NASA is simultaneously laying the groundwork for a permanent lunar presence that could, in the long term, host far-side observatories shielded from Earth’s radio and optical noise. The agency has awarded $590 million in contracts to Astrobotic, Firefly, and Intuitive Machines for cargo and science deliveries to the surface, with a first phase of a Moon base targeted for 2028 at a cost of $10 billion. Later phases envision pressurised habitats and power generation in the 2030s. The programme, part of the Artemis architecture, has been reshaped by the cancellation of the lunar Gateway station, redirecting funds toward surface infrastructure.

The immediate regulatory milestone falls to the U.S. Federal Communications Commission, which is reviewing applications from SpaceX and Reflect Orbital. ESO, together with the Royal Astronomical Society and the International Astronomical Union, has submitted formal comments urging the FCC to adopt the 100,000-satellite ceiling and a brightness cap. A decision on those dossiers will signal whether the U.S. regulator intends to treat optical astronomy as a protected interest alongside telecommunications and national security.