SpaceX safely de-orbits Starlink satellites

 From Tesmanian

SpaceX demonstrated on-orbit debris mitigation after a geomagnetic storm destroyed 40 Starlink satellites on February 4th. The satellites were launched to Low Earth Orbit (LEO) by a Falcon 9 rocket on February 3rd. Geomagnetic storms are a major disturbance of Earth’s magnetosphere that is caused when there is an exchange of high energy that comes from Solar wind into the space environment surrounding Earth. The geomagnetic disturbance caused the density of Earth's atmosphere to increase. The higher atmospheric drag in LEO caused 40 out of the 49 newly launched Starlink satellites to fall back to Earth. The satellites are designed to completely burn up in the atmosphere when they’re no longer operational to avoid creating space junk in orbit. Some of the satellites affected by the magnetic storm already burned up.

Sociedad de Astronomia del Caribe, a Puerto Rico astronomy non-profit organization, shared on February 7 that it captured a video of some of the brand new satellites burning upon atmospheric reentry, shown below. SpaceX intentionally deploys its satellites into lower orbits between 210 and 240 kilometers “so that in the very rare case any satellite does not pass initial system checkouts it will quickly be deorbited by atmospheric drag,” the company said. “While the low deployment altitude requires more capable satellites at a considerable cost to us, it’s the right thing to do to maintain a sustainable space environment.”

The company assured that the “deorbiting satellites pose zero collision risk with other satellites and by design demise upon atmospheric reentry—meaning no orbital debris is created and no satellite parts hit the ground. This unique situation demonstrates the great lengths the Starlink team has gone to ensure the system is on the leading edge of on-orbit debris mitigation,” said SpaceX.

For every mission, the company communicates with each newly launched Starlink satellite to see if it is working properly. If the satellites do not work they intentionally deorbit it to completely burn up in the atmosphere. If everything is working well, each satellite uses onboard Krypton-powered ion thrusters to slowly raise into an operational orbit of around 550-kilometers. The satellites in higher altitudes are unaffected by the atmospheric drag caused by geomagnetic disturbances.

SpaceX said that the recent geomagnetic storm “significantly impacted” the newly launched Starlink satellites. –“[…]  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,” the company shared in a press release. “Preliminary analysis show 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 reenter or already have reentered the Earth’s atmosphere.”

Source: Sociedad de Astronomia del Caribe