Ars Technica's SpaceX loses up to 40 satellites to geomagnetic storm after Starlink launch explains that a geomagnetic storm heated Earth's upper atmosphere (circa 200 km) so much that the aerodynamic drag due to the higher density was too much for its ion propulsion to overcome.
There are now several Sun observing spacecraft and spacecraft that observe the magnetic fields and solar wind between the Sun and Earth. But it seems there was no warning before launch that this would happen?
Question: Why didn't SpaceX see that geomagnetic storm coming? Was this a fluke or could this happen more frequently in the future?
We're currently between solar maxima, so I wonder if the current scheme only works circa solar minima when the chances of this happening are low?
- R.I.P. 40 lost starlinks = The Starlost
Ars Technica quotes a SpaceX statement:
Unfortunately, the satellites deployed on Thursday were significantly impacted by a geomagnetic storm on Friday. These storms cause the atmosphere to warm and atmospheric density at our low deployment altitudes to increase. In fact, onboard GPS suggests the escalation speed and severity of the storm caused atmospheric drag to increase up to 50 percent higher than during previous launches. The Starlink team commanded the satellites into a safe-mode where they would fly edge-on (like a sheet of paper) to minimize drag—to effectively "take cover from the storm"—and continued to work closely with the Space Force's 18th Space Control Squadron and LeoLabs to provide updates on the satellites based on ground radars.
Preliminary analysis shows the increased drag at the low altitudes prevented the satellites from leaving safe-mode to begin orbit-raising maneuvers, and up to 40 of the satellites will re-enter or already have re-entered the Earth's atmosphere. The deorbiting satellites pose zero collision risk with other satellites and by design demise upon atmospheric re-entry—meaning no orbital debris is created and no satellite parts hit the ground.