A string of about 30 lights travelling in unison have been seen high in the sky from Warkworth to Dargaville to Great Barrier Island this evening. Video / Tina Comrie / Lani Fairbairn / Supplied
They've already had bewildered Kiwis reaching for their phone cameras – and are a sight we can expect to see more of overhead. So what are Starlink satellites? Jamie Morton explains.
First off, what are they, exactly?
If you happen to see a peculiar-looking, chain-like object zipping across the sky at dusk or dawn, it's likely part of Elon Musk's grand vision of offering fibre-speed internet from above.
That's Starlink – a constellation of more than 1700 satellites operated by the tech billionaire's SpaceX, and which deliver internet access to remote spots as they communicate with ground-based transceivers from low Earth orbit.
The reason they first appear as a chain is because that's really what they are: stacks of dozens of flat-panel satellites, weighing just over a quarter of a tonne each.
With the help of krypton-fuelled ion thrusters, the satellites disperse and climb into their operating orbit, at an altitude of around 550km.
A Starlink satellite stack, as seen from space. Photo / Supplied
Most satellite internet services today come from single geostationary satellites that orbit the planet much higher, at about 35,000km.
Starlink began offering its public beta service to New Zealand customers last year, with monthly packages of unlimited data selling at $159 – but only after installing the dish and other hardware, costing an extra $799.
University of Auckland astronomer Professor Richard Easther said the satellites were easily distinguishable from the International Space Station, which could also be regularly spotted over New Zealand.
"While the ISS essentially appears as one bright light, the newly-launched Starlink satellites look like a whole bunch of stars, moving in unison with each other, in a line across the sky."
Once they moved higher up and joined orbit, they became harder to spot.
How often can we see them overhead?
Kiwis keen to spot the satellites have only to log on to one of several websites that track them.
A Starlink chain seen above Dargaville on Northland's west coast. Photo / Supplied
According to findstarlink.com, Aucklanders will be able to spot them moving southwest to northeast for six minutes at 5.37am tomorrow morning, or moving west to north for five minutes from 5.19am on Thursday.
The frequency of these passes, along with their odd appearance, has already caught the attention of many curious Kiwis.
One morning in May last year, Albany man Simon Russell was letting his cats out when he saw the satellites darting across the sky.
"It just looked too uniform to be something alien ... it looked like a satellite formation but then I've never heard of a string of 40 or 50 satellites all in a row."
Nelson-based space scientist Dr Duncan Steel agreed the spectacle created by the orbiting chain was what captivated people.
"I saw one a few nights ago coming over, although anybody throughout New Zealand would have been able to see the chain – it's quite a remarkable thing."
How fast the satellites were moving depended on their altitude at the time.
"But typically, things moving in low-Earth orbit are moving at about seven and a half kilometres a second, or about 27,000km/h."
Will we see more of them?
Steel said Kiwis could expect to see a lot more of the satellites if SpaceX went ahead with plans to expand its constellation.
Eventually, Musk wants to launch as many as 42,000 Starlink satellites – that's 25 times as many currently in orbit – with SpaceX initially focused on sending up around 4,400 into the first five orbital shells.
The latest launch of 49 satellites – via SpaceX's Falcon 9 rocket – took place only days ago.
SpaceX aims to launch more than 40,000 of its Starlink satellites, to bring space-based, high-speed internet service to all corners of the Earth. Photo / Supplied
"It seems they're launching them every couple of weeks now," Steel said.
And SpaceX wasn't the only player in this new space race: other major companies like OneWeb, founded by former Google innovator Greg Wyler, are also developing networks.
"It's almost like a land grab at the moment, with a lot of companies trying to get these constellations deployed, so if there's tighter regulation at some point in the future, they'll kind of be the incumbents," Easther said.
"And because they've got to deploy a lot of these things, you could imagine getting to the point where, if you're out in the bush and look up around dawn or dusk, you'd see a large number of moving points of light in the sky. That would be really weird."
Along with the purely aesthetic issue of more clutter in our skies, astronomers have raised some obvious issues.
They've suggested that the number of visible satellites might come to outnumber visible stars – and that their brightness, on optical and radio wavelengths, could disrupt scientific observations.
An image seemingly of Starlink satellites above Warkworth on Friday night. Photo / Supplied
Some scientists have warned this light pollution – which SpaceX has moved to address - could even affect astronomers searching space for Earth-threatening asteroids.
There have also been concerns the constellations could mess with future space travel, or worsen the already significant risk posed by space debris.
"A lot of the Starlink satellites are in relatively low orbits and aren't expected to remain up there forever - they will re-enter [the atmosphere] and that's a preferable thing to staying up there forever."
The problem was, he said, whether the satellites disintegrated into debris.
Some critics have warned of the risk of satellite collisions, potentially triggering a cascade of more collisions called the Kessler syndrome – and even keeping humans stuck on Earth.
SpaceX has said most of its satellites are launched at lower altitude, with failed satellites expected to deorbit within five years without propulsion.
