‘Cosmic Fireflies’ Spotted From the ISS Turn Out to Be a Total Buzzkill

A NASA astronaut captured brilliant specks of light floating above Earth’s horizon, dancing around in space. But rather than this being a celestial wonder, it’s actually a human-made phenomenon taking over Earth’s orbit.

Earlier this week, astronaut Don Pettit shared a video he had captured while on board the International Space Station (ISS). The video showed a group of flickering objects flying 250 miles (400 kilometers) above Earth’s surface. Pettit referred to the breathtaking scene as “cosmic fireflies” before giving us a reality check of what those glimmering lights are. “Actually, these are Starlink satellites momentarily flashing sunlight towards the [ISS],” Pettit wrote.

Cosmic fireflies. Actually, these are Starlink satellites momentarily flashing sunlight towards @Space_Station. pic.twitter.com/rOKUdLlP3f

— Don Pettit (@astro_Pettit) December 1, 2024

Bummer, right? The video that initially inspires cosmic wonder is actually a reflection of the reality of low Earth orbit today, littered with human-made objects that interfere with its natural beauty.

SpaceX first started launching its Starlink satellites in 2019 as a way to beam connectivity to remote areas or areas where internet connection is not reliable. There are more than 6,700 Starlinks currently in orbit, and that number is only increasing as SpaceX uses its Falcon 9 rocket to launch batches of the satellites to low Earth orbit.

The orbiting satellites have astronomers worried as they add a lot of noise to images captured by ground-based observatories, which they do by reflecting sunlight the same way that appears in Pettit’s video. The satellites mess with scientific data, appearing as bright streaks in astronomical images.

This is only the beginning as SpaceX wants to launch upwards of 42,000 of its internet satellites to orbit, although so far the Federal Aviation Administration has granted the company approval to launch 12,000 Starlinks. And that’s not to speak of other pending megaconstellations, including China’s “Thousand Sails” initiative, which could include upwards of 13,000 satellites.

Earlier this year, SpaceX began launching direct-to-cell (DTC) Starlink satellites, which are five times brighter than the rest of the broadband constellation, a recent study found. The DTC satellites, according to the study, may appear brighter due to their lower altitude. Regular Starlink satellites orbit at an altitude of 340 miles (550 kilometers) above Earth’s surface, while their DTC equipped counterparts orbit at a much closer distance of 217 miles (350 kilometers). Satellites in low Earth orbit circle the planet once every 90 minutes, and appear wider, or out of focus, when seen through telescopes, which further dilutes their light.

SpaceX is working with the International Astronomical Union and other astronomy groups on ways to mitigate Starlink’s interference with observations of the cosmos by reducing their reflectivity either by changing the orientation of the solar panels or installing a “sunshade” on the satellites. Those ideas are still in progress, and SpaceX isn’t slowing down on building its megaconstellation in the meantime.