A new report has revealed that the prototype BlueWalker 3 satellite in Low Earth Orbit (LEO), which was launched by AST SpaceMobile to provide 4G and 5G mobile (broadband) coverage to regular handsets on the ground, is so big that it outshines 99% of the stars visible from a dark location on Earth – that’s a problem.
The issue itself shouldn’t come as a surprise, as concerns have been raised before, due to the satellite’s design. The 1.5-ton BlueWalker 3 – orbiting at an altitude of a little over 500km – features a huge 693-square-foot (64.4-square-meter) phased array antenna (here). This makes the unfolded platform much bigger than other communication satellites, which creates a large and highly reflective surface.
The spacecraft needs an antenna that big because it’s been specifically designed for sending and receiving 4G and 5G mobile signals between the space-based platform and regular mobile handsets on the ground (early tests have gone well). Just one of these satellites has a Field of View (FoV) of over 300,000 square miles across the surface of the Earth.
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However, as we’ve already seen with the complaints raised by astronomers against SpaceX’s mass of significantly smaller Starlink platforms (something they’ve moved to tackle – here), highly reflective satellites can disrupt observational sciences (e.g. imaging/studying stars, planets and looking for dangerous asteroids etc.).
According to Nature, a group of professional and amateur astronomers recently embarked on an international observation campaign, ultimately spotting the BW3 satellite and recording its shine on the magnitude scale from locations in Chile, the United States, Mexico, New Zealand, the Netherlands and Morocco.
Extract from Nature’s Report
On 10 November 2022, the satellite unfurled its array of antennas, causing it to brighten to magnitude +0.4. If it were a star, it would have been one of the ten brightest in the sky. But its apparent brightness changes as the satellite rotates, and by late December, it had dimmed to a magnitude of +6. It then brightened again, reaching magnitude +0.4 once more on 3 April 2023.
The International Astronomical Union recommends that satellites in Low Earth Orbit (LEO) should have a maximum brightness of magnitude +7. BlueWalker 3 can be hundreds of times brighter, the authors found.
The real trouble here isn’t so much BW3 as the commercial satellites that are expected to follow. AST has plans to launch 5 commercial BlueBird satellites in the first quarter of 2024 (these will initially be of a similar size to the experimental BW3). But the company also holds an aspiration toward launching a total of up to 100 satellites, with future models being even larger and more capable.
The good news is that AST, much like Starlink before them, appears to be amenable to dimming its satellites and their next-generation ones are thus due to adopt anti-reflective materials, as well as using certain flight manoeuvres to reduce the crafts’ apparent magnitude. Only time will tell how effective this is. But whether other companies and countries will show a similar regard for these concerns remains to be seen.
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You really do need to wonder if these things are needed at all. Not only does it cause issues with protecting the planet and astronomy, it’s also a waste of resources getting these things into space.
It is already possible using satellite phones to make calls from almost anywhere on the planet for those explorers or emergency services that find themselves otherwise out of range, do we really need to expand that to 4G/5G everywhere so a dozen school children in some far flung village can get onto Facebook or watch cat videos on YouTube, which lets face it, doesn’t improve life for anyone but is rotting peoples brains.
Ultimately, these companies wouldn’t be investing if there wasn’t the demand for more effective global roaming solutions, and one way or another the market will resolve itself if there isn’t.
Phil Said:
>or watch cat videos on YouTube, which lets face it, doesn’t >improve life for anyone but is rotting peoples brains.
A bit uncalled for I think.
There are millions of unconnected people that can afford a low end 4G device but not a conventional satellite phone. Don’t assume that this is solving a first world problem.
“these companies wouldn’t be investing if there wasn’t the demand for more effective global roaming solutions, and one way or another the market will resolve itself if there isn’t”
It’ll be interesting to see what happens when even more businesses have used a lack of regulation to fill earth orbits with many thousands of satellites, the less successful businesses have gone bust, the larger numbers have resulted in a few impact losses and debris, and suddenly the space junk problem becomes very real.
Will those who paid to put all this stuff into orbit have paid into a clean up fund? No, I didn’t think so either.
There’s what we want and what we need. Some people can’t tell the difference. The bloke ahead of me in the queue wanted to watch footy on his phone. When I were a lad it would have been a pocket radio and an earphone.
Low orbit satellited can be useful for providing mobile coverage in low density and hilly areas
Somebody needs to give Anish Kapoor a call for a tub of Vantablack.
There is another interesting report were people are complaining about poles being put up in there street and these things are huge
My understanding is telephone poles are exempt from planning but not wireless masts do these may have been put up without consent
The poles were put up in Rochdale for IX wireless
How many of these LEO networks are there going to be?
This was a new one until I saw this news item.
Isn’t this a good case for having a just a few shared LEO networks rather then dozens all with hundreds of expensive satellites?
Dave G how well will a few shared leo networks keep prices down for the end user, any more than one shared copper wire network kept prices down?