SpaceX engineers, working alongside astronomers—including the scientific director of the Vera C. Rubin Observatory—have conducted a joint study on the impact of Starlink satellites on astronomical observations. The main concern: satellite brightness interfering with telescope imaging during nighttime operations. The findings show that SpaceX has honored its commitment to reduce satellite brightness. The new-generation Version 2 Starlink satellites are equipped with reflective film, painted black, and are significantly dimmer than earlier models—even though they are physically larger.
Modeling shows that even during the first hour of a summer night, only about 1.2 Version 1.5 and 0.93 Version 2 satellites out of 1,000 exceed magnitude 7—the brightness threshold where interference begins to affect telescope imaging. The impact could be further reduced by lowering orbital altitudes from 550 km to 350 km, which would reduce visible interference to about 0.56 satellites per 1,000. These improvements are especially important for the observatory’s decade-long program of nightly sky surveys.
However, the study did not factor in non-functioning satellites, or those in the process of orbit insertion or deorbiting. If the full Starlink constellation expands to 40,000 satellites, such transient objects could number in the dozens each day. Future megaconstellations from other companies may also pose risks—not only to the Rubin Observatory, but to other astronomical facilities including radio telescopes, for which lower orbits could introduce new challenges.
While SpaceX’s mitigation efforts have been positively received, the study concludes that broader, internationally coordinated regulation will be essential to protect ground-based astronomy as a whole from increasing satellite interference—both now and in the era of expanding satellite networks.
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