Commercial Satellite Threatens Astronomers’ Night Sky Observations
A super bright commercial satellite has been causing problems for astronomers trying to collect data on the night sky. Located about 330 miles above the Earth’s surface, the satellite is outshining most stars and posing a threat to astronomers’ research. The situation is expected to worsen as more companies plan to launch thousands of satellites into space without any regulations on their brightness.
In 2022, the Texas-based AST SpaceMobile company launched the BlueWalker 3 satellite into space with the goal of providing cellphone service across continents. However, the satellite turned out to be so brilliantly bright that it ranked among the top 10 brightest objects in the sky, according to a recent study.
Siegfried Eggl, a co-author of the study, expressed his astonishment, saying, “The satellite would be ranging among the top 10 brightest objects if you count the stars and the sun. It’s just incredible.” He believes that this is a consequence of the lack of consideration given to environmental factors when launching satellites.
The brightness of the BlueWalker 3 satellite was measured over a period of 130 days. Astronomers from various countries recorded its overpasses and evaluated its glow on a magnitude scale. The researchers found that the satellite registered at a brightness level of plus-0.4, which is significantly brighter than most objects in the night sky.
The main issue with the BlueWalker 3 satellite is its size. Its antenna array, which is as large as a squash court, reflects a significant amount of light back to Earth, making it appear so bright in the sky. Brad Young, an amateur astronomer, explained that once the satellite unfurled its antenna, it became 100 times brighter due to the increased area of the antenna reflecting light back.
The excessive brightness of the satellite has several implications, including the interference with data collection for astronomers. Streaks of satellites passing through the field of view could obstruct the visibility of objects such as asteroids. Additionally, the light pollution caused by these satellites affects radio astronomy and disrupts circadian rhythms and migratory patterns for animals.
SpaceX’s Starlink telecommunication satellites, which already pose a challenge for astronomers, will be further compounded by the brightness of the BlueWalker satellite. Each individual Starlink satellite is already 10 times brighter than desired by the astronomy community. SpaceX plans to launch 40,000 satellites, and the BlueWalker satellite’s prototype demonstrates that conditions are likely to worsen if regulatory measures are not implemented.
Several experts have called for stricter regulations to address this issue. Aparna Venkatesan, a cosmologist from the University of San Francisco, emphasized the need for operators to share specifications and employ tactics to darken their satellites. Astronomer Fabio Falchi, from the Light Pollution Science and Technology Institute, even called for a ban on bright satellites.
In his commentary, Falchi pointed out that the night sky is a cultural heritage that should not be spoiled. He highlighted the urgent need for action to preserve the experience of stargazing without the intrusion of satellites. As the number of satellites in space continues to increase, astronomers hope that companies will come together under a regulatory umbrella to prevent further light pollution and protect the night sky.