An NBN Co Internet outage in December was likely caused by a micrometeorite hitting a satellite.
Around 46,500 of NBN Co’s 112,000 satellite users in regional and remote parts of Australia were affected by a six-hour outage on 21 December.
NBN Co’s chief development officer for regional and remote Australia, Gavin Williams, told a Senate estimates hearing this week that the most likely cause was a micrometeorite hitting its Sky Muster satellite and causing the machine to rotate in its orbit.
“It cannot be 100 percent characterized as this, but all the evidence points to a micrometeorite that impacted the satellite,” he said. “It effectively makes [the] satellite’s body rotate while it remains in its orbit. So the satellite is no longer pointing at the appropriate spot on Earth [and] the payload – the transmission system on that satellite – is effectively switched off for that period.”
Sky Muster satellites are two geostationary (GEO) communications satellites built by Maxar-owned SSL and launched in 2015 and 2016 to provide rural connectivity. Weighing around 6.4 tons each, they provide download speeds of up to 25Mbps, and upload speeds of 5Mbps.
On the day of the event Sky Muster manager Optus informed NBN it had an "off-orbit condition of our second satellite," due to a micrometeorite hitting it. The satellite eventually rotated back around into the correct position, and after testing the service was resumed.
A micrometeorite is a micrometeoroid - a small particle of rock in space usually weighing less than a gram - that has survived entry through the Earth's atmosphere. The International Astronomical Union (IAU) defines meteorites as 30 micrometers to 1 meter, with micrometeorites the lower ~submillimeter range of the spectrum
Williams also noted that 573 customers went two weeks without Internet after the incident due to configuration errors in their NBN boxes preventing them from reconnecting to the service.
