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\n SpaceX wants to launch many more satellites<\/p>\n Charles Boyer \/ Alamy Stock Photo<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n Astronomers are scrambling to work out the environmental impact of a SpaceX application to launch 1 million satellites, as the deadline for its approval fast approaches.<\/p>\n On 30 January, SpaceX announced it had applied to send a vast mega-constellation of 1 million satellites into space with the Federal Communications Commission (FCC) in the US, which CEO Elon Musk said would act as orbital data centres for artificial intelligence.<\/p>\n The satellites would vastly outnumber anything else in orbit, with only 14,500 active satellites in space today. Currently, the FCC has no requirement to assess the potential environmental impact of launching so many satellites, including the effects on Earth\u2019s atmosphere or the changes to the night sky it would cause.<\/p>\n <\/p>\n \u201cWe\u2019re deeply concerned,\u201d says Ruskin Hartley, CEO of DarkSky International. \u201cWe\u2019re not opposed to satellites, but we believe it needs to be done in a responsible manner.\u201d<\/p>\n Following satellite applications, the FCC allows members of the public to comment, which it did for SpaceX\u2019s proposal less than a week after it was submitted \u2013 extremely fast compared with the typical months for other applications. The deadline for comments is 6 March, after which the FCC may spend months deciding whether to approve all, some or none of SpaceX\u2019s satellites.<\/p>\n So far, more than 350 comments have been submitted, with many astronomers raising concerns about the impacts on astronomy and Earth\u2019s atmosphere. \u201cA million satellites is completely terrifying,\u201d says Samantha Lawler at the University of Regina in Canada.<\/p>\n SpaceX hasn\u2019t revealed many details of the planned satellites, including their size or altitude. That has left astronomers like Lawler unable to work out exactly what the impact of the constellation would be. \u201cWe are scrambling to gather up the information that we need to write to the FCC,\u201d she says.<\/p>\n In a worst-case scenario, tens of thousands of satellites would be visible to the naked eye all night long, she says, and many times more would obscure the views of telescopes on Earth and in space. The satellites would also need to be continuously replenished, potentially every five years like SpaceX\u2019s Starlink satellites, meaning that, on average, one satellite would be launching and another would be re-entering the atmosphere every 3 minutes. Currently, only a handful of satellites re-enter Earth\u2019s atmosphere every day.<\/p>\n This could be hugely harmful to the planet\u2019s atmosphere. When satellites and rockets burn up, they produce aluminium oxide, or alumina, a substance that destroys ozone. \u201cWe\u2019re talking teragrams [1 trillion grams] of alumina,\u201d says Lawler. \u201cThis would cause massive ozone depletion and possibly change the temperature of the stratosphere.\u201d<\/p>\n The reason why the FCC isn\u2019t currently required to assess the environmental impact of any satellite application, even something of this scale, is because its space activities are exempt from the National Environmental Policy Act in the US. If a significant issue is raised in the comment process, that can trigger closer scrutiny of an application, but it isn\u2019t clear if that will happen, says Kevin Bell at the Free Information Group in Washington DC.<\/p>\n \u201cIn an ideal world, [the FCC] would study it,\u201d says Bell, but \u201cthey don\u2019t necessarily have the in-house scientific capacity to judge atmospheric impacts\u201d.<\/p>\n