A simulated image representing predicted satellite contamination in a future space telescope image.
NASA/Borlaff, Marcum, Howell
Every third image taken Hubble Space Telescope could be destroyed if space companies' plans to launch hundreds of thousands of satellites go ahead.
More than three-quarters of the nearly 14,000 satellites currently in orbit around Earth were launched in the past five years, many of them part of so-called megaconstellations such as Starlink, Elon Musk's satellite internet company. But those numbers could be dwarfed if space companies' proposals come to fruition, with plans to launch up to half a million satellites by the late 2030s, according to FCC filings.
Astronomers have already raised the alarm about how these satellites could affect telescopes on Earth, but now Alejandro Borlaff from NASA's Ames Research Center in California and his colleagues found that they could also seriously compromise space telescopes.
“When you put a telescope in space, it's usually a very pristine environment. There's no atmosphere, no city lights,” Borlaff says. “Now for the first time you have man-made objects that are somehow contaminating the images – it was very striking.”
Borlaff and his team used FCC and International Telecommunication Union documents to predict how many satellites could be launched in the next decade and their planned orbits. They then modeled how they might interfere with observations from four space observatories, including the Hubble and China's Xuntian telescopes, as well as the ARRAKHIS dark matter telescope, scheduled to launch in 2030, and the SPHEREx galaxy telescope, launched this year.
The team found that if 560,000 satellites were launched as planned, there could be an average of two satellite tracks for each Hubble photograph and about 90 for each Xuntian photograph due to the larger field of view and orbital altitude.
They tested their models, predicting that with the current number of satellites 4 percent Hubble images are affected by satellite tracksand this coincided with the analysis of real images.
Those predictions could come true if planned satellite launches go ahead, he says. John Barentine from Dark Sky Consulting, a company based in Tucson, Arizona, but it is unclear how many satellites will actually be launched. “Many experts believe that the number of satellites actually orbiting the Earth over the next 15 years will reach a steady state of around 50,000 to 100,000.”
If the actual number of satellites is only a tenth of what was planned, the impact on space telescopes will be much less severe, Barentyne says. “The number of traces per image will be only a few times higher than now for ARRAKHIS and Xuntian, and will remain virtually unchanged for SPHEREx and HST.”
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