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Nearly 4,400 Starlink satellites, currently orbiting at an altitude of approximately 550 kilometers (342 miles), will gradually descend to 480 kilometers (298 miles) during 2026. This maneuver affects a significant portion of SpaceX's operational fleet, which currently numbers nearly 9,400 spacecraft. The announcement was made by a company executive via the social network X.
A stack of Starlink satellites before their deployment in Earth orbit.
Credit: SpaceX
This decision is linked to the approach of a solar minimum period, expected around 2030. The Sun follows an activity cycle of approximately 11 years, and we have just passed the maximum of the current cycle. When solar activity is low, Earth's atmosphere contracts, which reduces atmospheric drag on satellites. By descending to a lower altitude, the spacecraft regain a potential for faster deorbiting in case of failure.
The reduction in deorbiting time goes from over four years to a few months, thereby improving the safety of circumterrestrial space. Michael Nicolls, vice president of Starlink engineering, explained on X that this measure reduces the risk of collision with other objects. The area below 500 kilometers (311 miles) has less debris and planned satellites, limiting potential dangers.
Earth's low orbit is becoming increasingly crowded, with Starlink representing about two-thirds of operational satellites. Other projects, such as Chinese internet constellations, plan to launch thousands of additional craft. This densification makes proactive trajectory management essential to avoid accidents.
The Starlink fleet is recognized for its reliability, with only two satellites currently out of service in orbit. Nevertheless, SpaceX wants to ensure rapid deorbiting in case of failure, especially in the face of uncoordinated maneuvers by other operators. These actions help maintain a safe space environment for all activities.
In the long term, this adaptation could serve as a model for other constellations, as low orbit exploitation intensifies. The lessons learned from this migration may help design sustainable strategies for the future of space.
The solar cycle and its effects on Earth's atmosphere
The Sun experiences regular variations in its activity, with a cycle lasting about 11 years. During maximum phases, it emits more radiation and particles, which warms and densifies the upper layers of Earth's atmosphere. Conversely, during minimums, the atmosphere cools and thins, altering orbital conditions.
These atmospheric changes have a direct impact on satellites in low orbit. A thicker atmosphere increases drag, slowing spacecraft and accelerating their descent toward Earth. Conversely, a rarefied atmosphere extends their orbital lifespan, sometimes requiring adjustments to ensure controlled deorbiting.
Satellite operators closely monitor these cycles to optimize missions. By anticipating periods of low solar activity, they can plan maneuvers like Starlink's, aimed at maintaining stable and safe orbits. This scientific understanding helps prevent risks related to space debris.
Beyond satellites, the solar cycle also influences communications and space weather. Studies conducted by institutions like NASA or ESA allow for better prediction of these phenomena, essential for modern space-dependent technologies.