SpaceX-owned Starlink is planning a massive reconfiguration of its constellation of over 4,400 satellites orbiting Earth and beaming internet to places. It"s VP of engineering, Michael Nicolls, announced that these 4400 satellites will be shifted from an altitude of 550 km (342 mi) to 480 km (298 mi) over the course of 2026, while working closely with other operators, regulators, and USSPACECOM.
"Lowering the satellites results in condensing Starlink orbits, and will increase space safety in several ways," Nicolls wrote. One of the reasons behind the project is that Solar Minimum is approaching in the late 2020s - it"s an 11-year cycle when the Sun"s activity reaches its minimum.
The Earth"s atmosphere gets thinner at higher altitudes during a Solar Minimum, which results in satellites feeling less drag at higher orbits. The reduced density makes it harder for a failed satellite to burn up, thereby increasing the risk that it could become a space hazard.
Shifting the satellites to lower orbits during solar minimum can cause them to burn up in months instead of years. Nicolls wrote that "as solar mininum approaches, atmospheric density decreases which means the ballistic decay time at any given altitude increases - lowering will mean a >80% reduction in ballistic decay time in solar minimum, or 4+ years reduced to a few months."
This will also reduce the risk of collision as the number of planned satellite constellations and debris objects is "significantly lower below 500 km." Starlink faced a close call recently when nine satellites were deployed from China without any known coordination with other operators.
Nicolls added in his X post that the shifting will further improve Starlink"s safety, particularly when dealing with unknown risks such as uncoordinated maneuvers and launches by other satellite operators. He noted that Starlink has delivered extremely high reliability with only two dead satellites in its fleet of over 9000 operational satellites.