If you look at the sky near Jupiter just after sunset, you might notice a bright new star, travelling fast across the sky.
This star is no planet or far-flung galaxy – it’s the largest commercial communications satellite in low-Earth orbit, the BlueWalker 3 satellite which has now unfurled its solar panels.
The apartment-sized satellite is a prototype from American company AST SpaceMobile, whose goal is to create a space-based mobile broadband network. This is only one of multiple satellites planned for the SpaceMobile constellation – some of which will be even bigger than BlueWalker 3.
Amateur astronomers have been reporting sightings of BlueWalker 3 over the last few weeks, many with an approximate brightness of 2nd or 3rd magnitude. This is moderately bright, but not as bright as Sirius – the brightest star in the night sky.
This means that some astronomers prediction that it “could outshine all stars and planets in the night sky” hasn’t come to pass.
However, a magnitude of 2 would put it in the rank of top 50 brightest stars.
If you wanted to track it for yourself, website Heavens Above has just created a new tool to track the satellite. You can also use In The Sky and note your location. Note that it can only be seen just after the Sun has gone down, as the Sun from below the horizon reflects onto the satellite, and makes it bright.
The goal with AST SpaceMobile is to create cellular broadband anywhere on the globe. Similar to Space X’s Starlink, many satellites are required to create full coverage around the world.
Astronomers and satellite operators are currently at odds over these satellite constellations. The more there, the more interference is likely for both optical and radio astronomy.
Read more: The largest commercial communications array ever has just launched. Expect to see it – it’s huge and bright
There’s also the question of what we – as humans – are comfortable with. Having 100s of these satellites in the sky at any one time would mean that when we look up, many of the bright lights in the sky would not be stars but satellites instead.
There’s also potentially issues about collisions in orbit making our skies unsafe.
There’s currently discussions happening between astronomers, satellite operators and the United Nations Committee on Peaceful Uses of Outer Space (COPUOS) about what is reasonable for satellites to be able to do in the night sky. The next meeting will occur in 2023.
“States are generally supportive, and we succeeded in ensuring that the radio and optical interference effects of large satellite constellations on astronomy are considered by the subcommittee,” Head of Assurance at the SKAO, Tim Stevenson said after the last meeting in February.
“We are looking forward to preparing and sustaining our case in COPUOS, which is the paramount forum in the world to deal with this issue.”
Originally published by Cosmos as Huge satellite BlueWalker-3 has now unfurled – and yes it’s very bright
Jacinta Bowler
Jacinta Bowler is a science journalist at Cosmos.
They were published in the Best Australian Science Writing 2023.
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