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arXiv · 2505.07194

Brightness Characteristics of the Qianfan Satellites and Evidence That Some Are Tumbling

Anthony Mallama·Richard E. Cole·Stephan Hellmich·Roger Spinner·Jeff Warner·Jay Respler
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Abstract

The mean apparent magnitude of the Qianfan satellites is 5.76 +/- 0.04, while the mean of magnitudes adjusted to a distance of 1,000 km is 5.24 +/- 0.04, based on 1,161 observations. Light curves of several spacecraft display rapid periodic fluctuations which indicate that they are tumbling. Nearly all of the non-tumbling satellite observations can be modeled with diffusely reflecting, Earth-facing surfaces. The Qianfan constellation will impact astronomical research and aesthetic appreciation of the night sky unless their brightness is mitigated.

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Anthony Mallama, Richard E. Cole, Stephan Hellmich, Roger Spinner, Jeff Warner, Jay Respler. 2025-05-12. Brightness Characteristics of the Qianfan Satellites and Evidence That Some Are Tumbling. https://arxiv.org/abs/2505.07194

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