Starlink and light pollution: Concerns for Kenya’s Astronomy Community

Starlink is a satellite-based internet project developed by SpaceX, the aerospace company founded by Elon Musk. The initiative aims to provide high-speed, low-latency internet across the globe, particularly focusing on remote and underserved regions where traditional internet infrastructure (such as fiber optics or cell towers) is difficult to deploy.

Kenya’s Astronomy Community

Kenya has been making significant strides in space science and astronomy over the past few decades. With the establishment of institutions such as the Kenya Space Agency (KSA) and partnerships with international space organizations, Kenya has positioned itself as a growing player in the field of space exploration and research.

Light Pollution from Starlink Satellites

One of the major concerns raised by the astronomy community regarding Starlink’s satellite constellation is the issue of light pollution. While the benefits of Starlink’s satellite-based internet service are undeniable, these satellites also create consequences that could hamper ground-based astronomical research.

1. Reflection and Brightness Each Starlink satellite, as it orbits the Earth, reflects sunlight, especially  during twilight and dawn hours, when the sun is below the horizon but the satellites are still illuminated. This reflection makes the satellites visible to the naked eye, appearing as bright streaks moving across the night sky. For casual stargazers, this may seem like an interesting phenomenon. However, for astronomers who rely on clear, dark skies to observe distant celestial objects, these bright streaks pose a serious problem.

Even though these satellites are small, their sheer number makes them highly visible from Earth. With plans for more than 10,000 satellites in Starlink’s final constellation, the cumulative effect could drastically increase the number of bright objects in the sky, disrupting long-exposure astronomical photography and making it difficult to study faint celestial bodies.

2. Interference with Astronomical Observations Astronomers, particularly those using ground-based telescopes, often rely on long exposure times to capture images of distant stars, galaxies, and other celestial objects. These exposures are vulnerable to any bright objects that pass through the telescope’s field of view. When a Starlink satellite crosses this field, it creates a streak of light that can obscure the data being collected. This interference forces astronomers to discard valuable observation time or apply complex image processing to remove the streaks, which is not always effective.

In Kenya, where astronomy is still an emerging field, this disruption is particularly concerning. With the development of local observatories and increased collaboration with international astronomical research efforts, the ability to collect uninterrupted data is essential for advancing the country’s space science capabilities. Unfortunately, the growing presence of Starlink satellites in the night sky means that Kenyan astronomers could face increasing challenges in their efforts to observe deep space phenomena and conduct meaningful research.

3. Specific Concerns for Kenya Kenya’s geographical location near the equator offers a unique vantage point for observing both the northern and southern hemispheres of the sky, making it an important region for global astronomical research. However, the influx of satellite constellations like Starlink could disproportionately affect Kenya’s astronomy community, as the satellites tend to be more visible during certain periods due to their lower orbital altitudes.

The Kenya Space Agency (KSA) and local institutions such as the University of Nairobi’s Department of Astronomy have expressed concerns that these satellites could hinder the country’s ability to fully participate in global astronomical projects, especially in fields like astrophotography, astrometry, and observational cosmology.

Efforts to Mitigate Light Pollution

Recognizing the concerns raised by the astronomy community worldwide, SpaceX has made attempts to address the issue of light pollution caused by its Starlink satellites. Several mitigation efforts have been proposed and implemented, though their effectiveness remains a topic of ongoing debate in the scientific community.

1. Technological Adjustments by SpaceX

To reduce the brightness of Starlink satellites and minimize their interference with astronomical observations, SpaceX has introduced several technological innovations:

DarkSat: In early deployments, SpaceX introduced DarkSat, a version of the Starlink satellite coated with a darker material to reduce its reflectivity. This modification aimed to make the satellites less visible to the naked eye and to ground-based telescopes. While DarkSat showed some improvement in reducing brightness, it did not fully solve the problem. Astronomers continued to report interference from these satellites, particularly in the early morning and late evening skies.

VisorSat: Following the limited success of DarkSat, SpaceX developed VisorSat, a new design where the satellites are equipped with sunshades, or visors, to block sunlight from reflecting off their surfaces. VisorSat has been more effective than DarkSat, reducing the brightness of the satellites by up to 50%. However, this reduction is still not enough to eliminate the problem entirely, as many satellites remain visible in the night sky and can still interfere with astronomical observations.

2. Astronomy Advocacy and Global Collaboration

The global astronomy community, including organizations such as the International Astronomical Union (IAU), has been actively engaging with SpaceX and other satellite operators to find long-term solutions to the light pollution problem. One of the key goals of these discussions is to establish regulatory standards that satellite operators must follow to minimize their impact on astronomy.

In Kenya, local astronomers and institutions have been part of these global discussions, advocating for stricter regulations and more robust measures to ensure that the country’s night skies remain clear for scientific research. The Kenya Space Agency (KSA), along with international partners, has been working to ensure that satellite operators, including SpaceX, consider the needs of developing nations whose scientific growth may be hindered by light pollution.

3. The Role of Governments and International Bodies

Governments and international regulatory bodies have a crucial role to play in mitigating the impact of satellite constellations like Starlink. There are ongoing discussions about establishing international guidelines for the brightness and positioning of satellites in orbit. These guidelines would help ensure that satellite operators take steps to minimize their impact on scientific research.

Conclusion

The deployment of Starlink satellites offers significant benefits, such as improving internet access in underserved regions like Kenya. However, the light pollution caused by these satellites poses a serious challenge to astronomy, particularly for ground-based telescopes. Despite efforts by SpaceX to reduce satellite brightness, such as through DarkSat and VisorSat, the growing number of satellites still threatens astronomical research. For Kenya, a country with a promising space research community, it is crucial to balance the need for global internet coverage with the preservation of clear skies for scientific advancement. Ensuring that technological progress does not hinder space research will be key to Kenya’s continued growth in space science.