SpaceX’s Falcon 9 rocket launch delivering Taiwan’s FORMOSAT-5 satellite to orbit back in August, 2017, ripped a huge hole in the Earth’s ionosphere according to a new study. The unusual trajectory of the rocket during the launch created an atmospheric shockwave 4 times bigger than the state of California, potentially disturbing global positioning and navigation systems.

While all rocket launches create shock acoustic waves (SAWs) - atmospheric disturbances traveling faster than the speed of sound – the SpaceX launch created the largest rocket-induced SAW on record. The shockwave is also significant because of its shape – rocket launches usually create V-shaped shockwaves; however Falcon 9 generated the first recorded circular shape.

The unusual SAW shape is a result of a unusual trajectory of the Falcon 9 launch. Contrary to popular belief, most of the time when spacecraft takes off, it does not ascend vertically to the Earth’s surface. Usually, shortly after the launch, rockets turn into the downgrade direction, nearly parallel to the Earth’s surface to limit gravity’s drag and stress on the spacecraft.

In contrast, Falcon 9 took off and continued to ascend vertically to the Earth’s surface, without turning horizontally. The rocket was able to go up straight into space, without maneuvering because of the unusually light payload. The Taiwanese satellite weighed only 75kg and bound for an orbit 720km above the Earth's surface, according to ARS Technica.

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Because of the uncommon trajectory of the ascent, maintaining nearly vertical direction all the way up through the Earth's ionosphere ranging from 60km to 1,000km the rocket created an unusual SAW shape. The Falcon 9 also punched a temporary, 900-km-wide hole into the plasma of the ionosphere.

"We've seen many cases of a rocket-produced disturbance, but there’s never been something that perfectly circular and with that large area," said study lead author Charles Lin, a geophysicist at the National Cheng Kung University in Taiwan.

 

  

The gigantic hole was a result of the interaction of water vapor in the Falcon 9's exhaust with charged particles in the ionosphere above California. These ionospheric disturbances can disrupt GPS signals and according to the research may have caused navigation errors of up to 1 meter for an hour or two after the launch. However the disruption remains a hypothesis as the scientists did not actually measure the correlation between signal accuracy and the launch.

While the navigational systems can usually adjust to such disturbances in the atmosphere, Lin claims that these may be more significant when it comes to autonomous driving systems with integrated GPS navigation results. According to the researcher, these inconsistencies are becoming more important, especially with the increasing launches of spacecraft.

“Humans are developing more powerful rockets to send cargoes to other planets. These two factors will gradually affect the middle and upper atmosphere more, and that is worthwhile to pay some attention to," Lin noted.