The August launch by SpaceX of a communications satellite created the largest rocket shockwave in the atmosphere ever measured.
In the new study, Lin and his colleagues used GPS signals to determine how the FORMOSAT-5 launch affected the upper atmosphere. They found Falcon 9’s vertical trajectory created a circular shock wave above the western United States that had never before been seen from a rocket launch. The only similarly-shaped shock wave Lin had seen was from an eruption of Russia’s Sarychev volcano in June 2009.
Not only was the shock wave circular, it was also the largest one Lin had ever seen – roughly four times the area of California. In the new study, he ran computer simulations of rocket launches and found the momentum from a vertical trajectory would tend to create a much stronger atmospheric disturbance than a curved one, which could explain why the shock wave was so large.
In addition to creating a gigantic shock wave, the launch created a hole in the ionosphere above California. Water vapor in the rocket’s exhaust reacted with the ionosphere’s charged particles to create a hole in the plasma layer that took up to two hours to recover.
The rocket’s vertical trajectory was because the overall payload was light. Heavier payload cause the trajectory to curve more as the rocket rises.