A team of researchers from the US military’s Defense Advanced Research Projects Agency (DARPA) made an unexpected discovery while monitoring the atmosphere using their AtmoSense program. The team was tracking sound waves created by controlled explosions in New Mexico when they noticed a significant drop in total electron content, which puzzled them.
Analysing further, the team discovered that this phenomenon is caused by objects reentering Earth’s atmosphere, such as a SpaceX Falcon 9 rocket plummeting towards its landing site. DARPA hopes to use this technique to detect underground explosions or other national security threats using signals detected from the atmosphere.
The discovery has significant implications for tracking reentering objects and could potentially be used to monitor future launches. The researchers behind AtmoSense will share their findings in an upcoming virtual workshop starting April 15, where they plan to showcase a new technique for identifying objects reentering the atmosphere.
Source: https://gizmodo.com/darpa-unintentionally-invents-new-rocket-radar-thanks-to-spacex-2000584008