In recent years, the rapid proliferation of low-Earth orbit satellites has led to increasingly crowded orbital pathways, bringing the issue of space safety into sharp focus. In the early hours of the morning Beijing time, Elon Musk's SpaceX announced it will lower the orbital altitude of thousands of its Starlink satellites to mitigate collision risks. Michael Nichols, Vice President of the Starlink project, stated the company is "initiating a major constellation reorganization plan" to move all satellites currently operating at approximately 550 kilometers (342 miles) down to an orbit of about 480 kilometers (298 miles). This maneuver aims to relocate the satellites to a less congested orbital shell, thereby reducing collision risks and enabling faster deorbiting and atmospheric burn-up for any satellites that malfunction or fail, which would subsequently decrease space debris generation. According to Nichols, approximately 4,400 Starlink satellites will participate in this orbital descent within the year.

Beyond creating a relatively safer and more controlled operational environment for the satellites, Nichols pointed out that this adjustment is also closely tied to the solar activity cycle. Solar activity, which follows an approximately 11-year cycle, directly influences the density of Earth's upper atmosphere. The next solar minimum is predicted for the early 2030s; as it approaches, the density of the upper atmosphere will decrease. This means the natural orbital decay time for satellites at the same altitude will lengthen. By lowering their orbital altitude, the decay time—which could otherwise extend beyond four years during the solar minimum—can be shortened to just a few months, increasing the orbital decay rate by over 80%.

Additionally, lowering the satellite orbits could theoretically reduce signal latency. However, since not all latency is attributable to satellite distance, the improvement from a 70-kilometer altitude change is expected to be minimal. It is noteworthy that this decision to lower orbits comes amidst a contentious backdrop. As reported, on December 29th local time, a Chinese representative stated at a UN Security Council Arria-formula meeting on low-Earth orbit satellites that the unchecked expansion of commercial satellite constellations by certain countries, lacking effective regulation, poses significant safety challenges.

Citing the Starlink project under Musk's company as an example, the representative noted that Starlink has over 10,000 satellites in orbit, which have reportedly necessitated two emergency collision-avoidance maneuvers by the Chinese space station. Recently, the disintegration of one satellite generated more than 100 fragments, severely threatening spacecraft from developing nations that lack orbital control capabilities. Previously, SpaceX confirmed an anomaly with one of its Starlink satellites, potentially caused by an internal minor explosion leading to a propellant tank leak, a rapid decay in its semi-major axis of about 4 kilometers (2.5 miles), and the release of debris.

Overall data indicates that low-Earth orbit is becoming unprecedentedly crowded. Last year alone, SpaceX added over 3,000 new satellites through 121 launch missions, averaging nearly one new satellite launch every three days. According to a 2024 World Economic Forum report, the number of low-Earth orbit satellites is projected to grow by 190% over the next decade. A collision or explosion involving satellites could generate vast amounts of debris scattered throughout the orbital environment. This space junk increases the risk of subsequent collisions, threatening active satellites and future space missions, and potentially triggering a "Kessler Syndrome" scenario.

The "Kessler Syndrome" is a theory proposed by a NASA scientist, suggesting that once space debris reaches a critical density, collisions could trigger a chain reaction. This cascade would generate even more fragments, potentially rendering certain orbital regions unusable.