Starlink satellites reentering Earth’s atmosphere in increasing numbers, creating artificial meteor showers

Starlink satellites are re-entering Earth’s atmosphere in increasing numbers, producing artificial meteor showers visible in the night sky.

In January 2025 alone, at least 120 of them burned up upon reentry, with an estimated 4 to 5 deorbiting and incinerating daily, according to Jonathan McDowell, an astronomer at the Harvard Center for Astrophysics who tracks satellite activity.

This surge in reentries is part of SpaceX’s planned decommissioning of first-generation (Gen1) Starlink satellites to make way for newer models. “More than 500 of the 4 700 Gen1 Starlink satellites have now reentered,” McDowell noted.

Artificial meteor showers

Starlink satellites produce artificial meteor showers when they re-enter Earth’s atmosphere and burn up due to intense friction with the air.

As the satellites descend from orbit, they reach speeds of approximately 27 000 km/h (16 800 mph). Upon hitting the denser layers of the atmosphere, aerodynamic forces cause extreme heating, leading the satellite’s structure to disintegrate and vaporize. This process generates bright streaks of light across the sky, similar to natural meteors burning up upon entry.

The burning debris is often visible for several seconds, depending on the size and composition of the satellite. Some larger fragments may survive longer before vaporizing completely, while metallic byproducts such as aluminum oxide are released into the upper atmosphere.

As the number of Starlink reentries increases, these artificial meteor showers are becoming more frequent, often mistaken for natural celestial events by skywatchers.

Aluminum deposition and ozone depletion risk

Satellites are engineered to disintegrate upon atmospheric reentry, ensuring that most of their mass vaporizes before reaching Earth’s surface. However, recent studies indicate that some metallic compounds, particularly aluminum oxide, are released into the atmosphere during this process.

A typical 250 kg (550 lb) satellite can produce approximately 30 kg (66 lb) of aluminum oxide nanoparticles during reentry. These particles can persist in the atmosphere for decades, potentially affecting atmospheric chemistry.

A 2023 study revealed that about 10% of stratospheric sulfuric acid particles larger than 120 nanometers in diameter contain aluminum and other metals originating from the burn-up of satellites and rocket stages during reentry.

The increasing concentration of aluminum oxide in the atmosphere raises concerns about potential long-term environmental impacts, including ozone depletion. Aluminum oxides can catalyze chlorine activation, which contributes to the breakdown of ozone molecules.

Molecular dynamics simulations of the aluminum oxidation process during satellite reentry have shown that byproducts tend to form clusters of aluminum oxide, especially in oxygen-limited environments. These clusters can remain in the atmosphere for extended periods, further contributing to ozone depletion.

As the number of satellite reentries increases, understanding and mitigating the environmental impacts of aluminum oxide accumulation in the atmosphere become increasingly important.

According to the study, approximately 24 kg (53 lb), or 32%, of the aluminum in a typical 250 kg (550 lb) satellite oxidizes upon reentry, leading to the formation of about 29.8 kg (66 lb) of aluminum oxide.

In 2022, the total amount of aluminum released from all satellites reentering from Low Earth Orbit (LEO) was approximately 41.7 metric tons (46 US tons), exceeding the natural contribution from micrometeoroids by 29.5%. This resulted in the formation of about 16.6 metric tons (18.3 US tons) of aluminum oxide in the mesosphere that year.

Projections indicate that if satellite reentry rates continue to increase, excess aluminum in the upper mesosphere could surpass natural levels by over 640% annually, potentially reaching more than 360 metric tons (397 US tons) of aluminum oxide clusters per year.

When oxygen interacts with aluminum, it forms aluminum oxide clusters, while larger aggregates of unoxidized aluminum may remain intact. These byproducts can take up to 30 years to descend from the mesosphere to the stratospheric ozone layer. At around 40 km (25 miles) altitude, aluminum oxides can catalyze reactions that activate chlorine, contributing to ozone depletion.

This suggests that aluminum oxide accumulation in the mesosphere can increase long before its impact on ozone concentration is observed in the stratosphere, leading to a delayed effect between satellite reentry and measurable ozone depletion.

Currently, there are no international regulations addressing the long-term atmospheric impact of satellite reentries. While agencies such as NASA and ESA track space debris, environmental monitoring of metallic oxides from satellite burn-ups remains limited.

Some researchers suggest that future spacecraft could be designed with biodegradable materials or alloys that fully vaporize without producing persistent aerosols. However, industry-wide adoption of such materials would require significant regulatory and engineering changes.

References:

¹ Potential Ozone Depletion From Satellite Demise During Atmospheric Reentry in the Era of Mega-Constellations – José P. Ferreira,  Ziyu Huang,  Ken-ichi Nomura,  Joseph Wang – Geophysical Research Letters – June 11, 2024 – https://doi.org/10.1029/2024GL109280

² What’s up in space – Spaceweather.com – February 6, 2025