As approval deadlines loom, astronomers are working diligently to assess the environmental implications of SpaceX’s request to launch up to 1 million satellites.

On January 30, SpaceX revealed its application to the US Federal Communications Commission (FCC) to deploy a vast constellation aimed at serving as an orbital data center for artificial intelligence, as stated by CEO Elon Musk.

This proposed number of satellites far exceeds the current total in orbit, which stands at only 14,500 active satellites. At present, the FCC is not mandated to evaluate the potential environmental consequences of launching such a significant number of satellites, especially regarding their impact on Earth’s atmosphere and nighttime visibility.

“We have serious concerns,” remarked Ruskin Hartley, CEO of DarkSky International. “We support satellite use, but it must be conducted responsibly.”

Following satellite applications, the FCC allows public comments. This process occurred shortly after SpaceX’s proposal, which is swift compared to typical timelines. The deadline for submissions is March 6, after which the FCC might take several months to decide on the application.

More than 350 comments have been submitted thus far, with many astronomers voicing their apprehensions about the implications for astronomy and Earth’s atmosphere. “The idea of a million satellites is incredibly alarming,” noted Samantha Lawler from the University of Regina, Canada.

SpaceX has not disclosed extensive details about the proposed satellites, specifically regarding their sizes and altitudes. This lack of information prevents astronomers from fully understanding the potential impacts of the constellations. “We are hurrying to gather crucial data to submit to the FCC,” Lawler added.

In a worst-case scenario, Lawler suggests that tens of thousands of satellites could be visible to the naked eye simultaneously, greatly obstructing observations from telescopes both on Earth and in space. Furthermore, it would necessitate continual satellite replenishment, likely every five years, similar to SpaceX’s Starlink system. Consequently, an average of one satellite would launch and another would re-enter Earth’s atmosphere every three minutes—significantly more than the current rate of a few re-entries daily.

This frequent re-entry poses serious risks to Earth’s atmosphere, as burning satellites produce aluminum oxide, a substance harmful to the ozone layer. “We’re discussing Teragrams [1 trillion grams]. This could lead to substantial ozone depletion and alter stratospheric temperatures,” Lawler warned.

The FCC currently lacks the obligation to evaluate the environmental impacts of satellite usage at such a comprehensive scale, due to exemptions under the U.S. National Environmental Policy Act. Should significant concerns arise during the public comment period, the application may face closer scrutiny; however, the likelihood of this remains uncertain, according to Kevin Bell from the Free Information Group in Washington, D.C.

“Ideally, the FCC would conduct assessments, but they often lack the scientific capacity to fully evaluate atmospheric impacts,” Bell explained.

Neither the FCC nor SpaceX has responded to requests for comment.