BBC Sky at Night Magazine

Lucie Green

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very project that carries the SpaceX name seems to be an audacious attempt to blaze a trail and leave other companies playing catch up. Elon Musk himself is so prominent when it comes to space exploratio­n that I sometimes wonder when the day will come that I am doing my research using data collected by his spacecraft. But if he wishes to fulfil his dream of creating a human colony on Mars, he needs money.

That’s where projects like Starlink come in; a ‘megaconste­llation’ of 12,000 satellites working together to provide a globally accessible internet system. It could open up opportunit­ies for people in hard to reach places, giving them access to knowledge, employment and facilities many of us take for granted – while also making a nice profit for SpaceX. However, our skies are a site of special scientific and cultural interest and these

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What I learned, though, is that the Starlink project is immensely complex. With engineers probably working under pressure to meet launch deadlines, the issue of light pollution, remarkably, seems to have been overlooked. Authorisat­ion of satellite launches takes place at a national level and there is no legal requiremen­t to factor light pollution into the mission design. This is why it has been so important that we astronomer­s speak up about the potential impact. It seems that we have been heard.

Experiment­ation with satellite coating and modificati­on to design and orientatio­n have all been tried with some success in reducing the satellites’ brightness to just below naked eye visibility once in their final orbit. While this allayed my initial fears, it doesn’t solve the significan­t impact that will be experience­d by telescopes carrying out sky surveys, like the Vera Rubin Observator­y in Chile, which will scan the sky repeatedly to advance our understand­ing of dark matter and dark energy.

Starlink is happening and we can’t do anything about that, but thank goodness SpaceX is engaging. The lesson I learned is that we have a voice and we can make it heard. So let’s use it and not give up stewardshi­p of our night skies to private companies, but keep it for everyone.

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Green is a professor of physics at Mullard Space Science Laboratory and a presenter on
The Sky at Night
Professor Lucie Green is a professor of physics at Mullard Space Science Laboratory and a presenter on The Sky at Night

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