A geomagnetic storm triggered by a large burst of radiation from the Sun has disabled at least 40 of the 49 satellites newly launched by SpaceX as part of its Starlink internet communications network.
The incident was believed to mark the largest collective loss of satellites stemming from a single geomagnetic event, and was unique in the way it unfolded, Harvard-Smithsonian astrophysicist Jonathan McDowell said.
SpaceX said the satellites were hit last Friday, February 4, a day after being launched into a preliminary "low-deployment" orbit about 210 kilometres above Earth.
Elon Musk's company said it routinely put satellites into low orbits in order to be able to crash them back to Earth and incinerate them on re-entry if malfunctions were detected during initial system checks.
But it was not clear if the company had anticipated the severity of the extreme space weather conditions it faced.
Weather alert in space before launch
The Thursday launch by a SpaceX Falcon 9 rocket flown from the Kennedy Space Center in Florida roughly coincided with a "geomagnetic storm watch" posted for last Wednesday and Thursday by the US Space Weather Prediction Center.
The alert warned that solar flare activity from a "full halo coronal mass ejection" — a large blast of solar plasma and electromagnetic radiation from the Sun's surface — was detected on January 29, and was likely to reach Earth as early as February 1.
The alert also said resulting geomagnetic storm conditions on Earth were "likely to persist" into February 3 "at weakening levels."
According to SpaceX, the speed and severity of the solar storm drastically increased atmospheric density at the satellites' low-orbit altitude, creating intense friction or drag that knocked out at least 40 of them.
Starlink operators tried commanding the satellites into a "safe mode" orbital configuration, allowing them to fly edge-on to minimise drag.
But those efforts failed for most of the satellites, forcing them into lower levels of the atmosphere where they burned up on re-entry, SpaceX said.
He said he believed it marked the single greatest loss of satellites from a solar storm, and the first mass satellite failure caused by an increase in atmospheric density, as opposed to bombardment of charged particles and electromagnetic radiation itself.
Dr McDowell said the incident raised questions of whether the elevated orbital drag caused by the storm exceeded design limits or whether SpaceX believed incorrectly that the satellites could handle so much density.
He said that if "they weren't expecting to have to handle that much density … it sounds like they weren't paying attention to the space weather reports".
SpaceX did not immediately respond to a request for comment.
The Los Angeles area-based rocket company, founded by billionaire entrepreneur Elon Musk, has launched hundreds of small satellites into orbit since 2019 as part of his Starlink service for broadband internet.
In a January 15 tweet, Musk said the network consisted of 1,469 active satellites, with 272 moving to operational orbits.
ABC/wires
