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Issue 105

08 Flash Archive · Members Only

Observers Report on Qianfan Impact to Astronomy

26 Aug: Report in Sky & Telescope by Anthony Mallama provides initial observations of the 18 Qianfan (2024-140) satellites China launched on 6 Aug 2024 (this was the LM-6A that generated ~700 pieces of debris). Per the article, amateur astronomers have shown that the satellites are bright enough to be seen with the…

Author Greg Gillinger Published July 25, 2025
  • 26 Aug: Report in Sky & Telescope by Anthony Mallama provides initial observations of the 18 Qianfan (2024-140) satellites China launched on 6 Aug 2024 (this was the LM-6A that generated ~700 pieces of debris). Per the article, amateur astronomers have shown that the satellites are bright enough to be seen with the naked-eye. While SpaceX/Starlink have engaged with the Astronomical community to lessen the impact of the Starlink satellites to terrestrial astronomy, it is unknown if China intends to make the same effort. Excerpts below. Watch Video.

– Qianfan means Thousand Sails and it will add 14,000 new communication satellites to the already crowded space in low-Earth orbit. Two more Chinese mega-constellations are planned to follow Qianfan.

– The Thousand Sails spacecraft are in polar orbits inclined 89° to Earth’s equator at altitudes near 800 kilometers (500 miles). That height is above the Starlink satellites, operated by SpaceX, and below those of the OneWeb constellation from Eutelsat.

– Experienced visual satellite observers began recording brightness once the ephemeris data became available. One observer in southwestern UK noted that the spacecraft were apparent magnitude 4.6 on August 15th. Another observer measured visual magnitude of 6.1 and 5.1 on successive passes over northern Belgium on August 16th. From Bowie, Maryland the satellites appeared to be magnitude 5.2 a few hours later and then at 5.8 on August 21st.

-The data indicate brighter magnitudes at greater heights and suggest that the spacecraft shine at about magnitude 4 near zenith. That brightness compares to the magnitude 4.3 from a video recorded as the satellites passed almost straight overhead.

– Besides the Thousand Sails project, two other large Chinese satellite constellations are under development. The China National Network Group is planning for 13,000 spacecraft in their Guowang (also referred to as SatNet) constellation. And commercial manufacturer Landray Hongqing is building the Crane-3 constellation, which will field an anticipated 10,000 more satellites according to the company’s filings. Altogether, the three constellations would tally up to 37,000 spacecraft.

The Thousand Sails spacecraft at their current brightness would seriously interfere with astronomical research as well as aesthetic appreciation of the night sky. In the U.S., SpaceX is working with astronomers to address the problem of bright spacecraft, and Starlink has succeeded in reducing the brightness of its satellites by 90%. There are, however, no regulations in place as yet that govern satellite brightness.