Increasing Satellite Traffic Threatens Astronomical Observations
The growing number of satellites orbiting Earth is posing a meaningful and escalating challenge to astronomical research,notably impacting telescopes like the Hubble Space Telescope. The issue stems from cheaper launch costs and the rapid expansion of satellite constellations, such as those deployed by Starlink, opening up a complex set of problems for space-based observation.
Between 2018 and 2021, satellite trails – appearing as streaks of light in images – were detected in 4.3 percent of images captured by the Hubble. This problem is intensifying as the total number of satellites in orbit has surged from 5,000 in 2019 to over 15,800 today, according to the European Space Agency. Projections indicate this number could climb to as many as 560,000 within the next decade if planned launches proceed as scheduled.
Recent simulations conducted by researchers suggest the impact on future observations will be substantial. they project the Hubble telescope could inadvertently capture an average of 2.14 satellites per exposure. The upcoming Chinese Space Station Telescope Xuntian, expected to launch next year, is predicted to see an even greater number, averaging 92 satellites per exposure, due to its wider field of view. Fortunately, telescopes like the James Webb Space Telescope, orbiting at a greater distance from Earth, are currently unaffected by this light contamination.
The presence of satellites isn’t merely an aesthetic issue; it directly hinders scientific data collection. Satellites reflect sunlight, moonlight, or Earth’s light, creating brightness that can obscure faint details in images. As researcher Boris Borlaff explains, this can prevent the detection of subtle changes in a star’s brightness, possibly masking the presence of orbiting exoplanets. “You will lose that data because a satellite passed in front of you,” he stated.
Addressing this issue requires proactive solutions. Attempts to create darker, less reflective satellites have encountered challenges, as these designs tend to generate more infrared light due to increased heat.Researchers are also exploring strategies to schedule observations during times and locations with lower satellite traffic, a task becoming increasingly difficult with the growing congestion. Borlaff emphasizes the need for increased coordination between satellite operators, governments, and astronomers, potentially through regulating satellite deployment locations – perhaps placing them in lower orbits – to minimize interference.
“there has to be an optimal way to place constellations and space telescopes … so we can coexist in a sustainable way,” Borlaff concludes, highlighting the urgency of finding a balance between expanding space infrastructure and preserving the integrity of astronomical research.
