Unraveling the Ripples in the Sky: How Rocket Launches Disturb the Ionosphere

Scott Thaller, Research Scientist 

Rocket launches are known to unleash spectacular forces, propelling engineering marvels into space while creating shockwaves that ripple through the atmosphere. But did you know these events also send disturbances soaring into the ionosphere, the electrically charged upper layer of Earth’s atmosphere? These disruptions, known as traveling ionospheric disturbances (TIDs), provide a fascinating window into the interplay between rocket launches and the environment above us. 

To better understand this phenomenon, Orion has developed a unique radar instrument called TIDDBIT (TID Detector Built in Texas). This novel tool helps shed light on the invisible waves created during rocket launches and reveals their structure and movement within the ionosphere. 

HOW ROCKET LAUNCHES SHAPE THE IONOSPHERE 

When a rocket launches, it generates two types of waves: atmospheric gravity waves, which are akin to ripples spreading across a pond, and shock acoustic waves, which behave more like sound waves. As these waves propagate upward, they disturb the ionosphere, creating TIDs. These are literally ripples in the sky, caused by vertical motions in the ionosphere’s charged particle layers. 

TIDDBIT, a high-frequency continuous wave sounder, detects these disturbances by bouncing radio signals off the ionosphere. As the waves push the ionosphere’s layers up and down, the reflected radio waves experience a Doppler shift in frequency. By measuring these shifts at multiple reflection points in the ionosphere, scientists can reconstruct the wave patterns. This includes mapping critical parameters such as wavelength, phase speed and propagation direction, as well as determining how these properties vary across three dimensions. 

WHY THIS RESEARCH MATTERS 

Understanding how rocket launches influence the atmosphere and ionosphere is critical not only for advancing space science but also for detecting and tracking an increasing number of human-made activities in space.  

As more satellites are launched and spaceports become busier, these insights help ensure that we can continue to safely navigate and operate in Earth's upper atmosphere. The research also advances our theoretical understanding of wave dynamics in the ionosphere and can inform models used in atmospheric and space weather prediction.

RECONSTRUCTING THE SKY’S RIPPLES 

The TIDDBIT radar operates at two fixed high frequencies to probe different altitudes in the ionosphere. Using cross-spectral analysis, it separates the wave components and estimates parameters like wave period, propagation direction and vertical movement. This innovative technique delivers a detailed view of the structure and movement of TIDs, offering unmatched insight into how rocket launches disturb the upper atmosphere. 

The Florida TIDDBIT sounder was active during numerous rocket launches from Cape Canaveral between 2015 and 2022. Data from these observations reveal that TIDs often emerge about 10 to 20 minutes after a rocket launch, displaying wave periods of approximately 14 minutes. These characteristics align with the expected speeds at which atmospheric gravity waves travel from the launch site to the TIDDBIT detection location, about 200 km northwest of Cape Canaveral. Additionally, the data confirms that the waves propagate directly from Cape Canaveral, providing clear evidence of their origin. 

Rocket launches are not just technological triumphs or milestones in space exploration; they are also drivers of natural phenomena high above us. Using tools like TIDDBIT enables scientists to quantify these atmospheric disturbances and better predict how increasing launch activity may affect ionospheric conditions, radio communications, and navigation systems. 

Click the link below to view the presentation of this work.  

Thaller_AGU_2024_RocketTIDs.pdf

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