In a startling event, a SpaceX rocket explosion last year caused an unexpected and rare disturbance in Earth’s upper atmosphere. This incident is the first time scientists have observed a human-made explosion creating such an effect in the ionosphere, a part of our atmosphere that is crucial for radio communication and satellite operations.
The Unplanned Explosion and Its Impact
On November 18, 2023, SpaceX launched its massive Starship rocket from its facility in Boca Chica, Texas. The rocket, which is the largest and most powerful ever built, was on its second test flight. Everything seemed to be going as planned until about four minutes after liftoff when the rocket’s first stage, the large lower part containing the main engines, detached as expected. However, instead of landing back on Earth as intended, the first stage unexpectedly exploded.
Just four minutes after that, the upper part of the rocket, which had continued its journey, also met a fiery end. A fire broke out due to the rocket venting liquid oxygen, and soon after, the rocket exploded in what engineers describe as a “rapid unscheduled disassembly” at a height of about 93 miles (150 kilometers) above the Earth’s surface. This explosion was so powerful that it temporarily ripped a hole in the ionosphere, a layer of our atmosphere filled with ionized gases.
A Rare Atmospheric Disturbance
The ionosphere is a region of the Earth’s atmosphere that stretches between 50 and 400 miles (80 and 650 kilometers) above the Earth’s surface. It is crucial because it contains gases that have been ionized, meaning they have been stripped of electrons and turned into plasma. This layer is essential for radio communications and is also where auroras occur.
A sizable, transient hole in the ionosphere was caused by this explosion, according to a recent research by Russian scientists. Such holes are usually formed by chemical reactions from rocket fuel, but this was the first time a hole was caused by the shock wave of an explosion. The disturbance, observed by multiple satellites and ground-based stations around the world, lasted for 30 to 40 minutes before the ionosphere returned to normal.
The Science Behind the Ionospheric Hole
Human-made holes in the ionosphere are not entirely new. The fact that molecules from rocket fuel, such carbon dioxide and water vapor, can react with ionized oxygen atoms in the ionosphere and cause these atoms to recombine into ordinary oxygen has long been known to scientists. This reaction temporarily creates a gap, or hole, in the plasma that fills this atmospheric layer.
SpaceX’s Falcon 9 rockets have been known to create such holes, especially when they separate their stages or dump fuel during reentry. These events sometimes create stunning red auroras in the sky, known as “SpaceX auroras.” However, the hole created by the Starship explosion was different. It was caused by the shock wave of the explosion scattering the free electrons in the ionosphere, disrupting the plasma in that region. Unlike the chemical-induced holes, this disturbance did not result in a visible aurora.
Although the implications of such ionospheric holes are not well understood, the researchers stressed that they present a unique opportunity to investigate this important component of the environment. Events like this help scientists learn more about the structure and behavior of the ionosphere, which is important for understanding how it influences communication systems and other technologies that rely on this layer of the atmosphere.
This was the second time that one of SpaceX’s 400-foot-tall (120 meters) rockets exploded during a test flight. The first explosion occurred on April 20, 2023, when the rocket spun out of control just four minutes after liftoff and had to be destroyed at an altitude of about 18 miles (29 kilometers). Unlike the November incident, the April explosion did not cause an ionospheric hole because it happened at a much lower altitude, where the shock waves could not reach the ionosphere.
In the aftermath of these two explosions, SpaceX continued its testing, and on March 14, 2024, the Starship rocket finally made it to orbit in one piece. The rocket was last seen above the Indian Ocean, but it was lost during reentry.
This rare atmospheric event caused by the Starship explosion is a reminder of how powerful human-made technologies can interact with our planet’s delicate systems. It also highlights the importance of continuing to study and understand these interactions, as they can have significant effects on our environment and the technologies we rely on every day.
