The asteroid, which was
once thought to be a risk to Earth in 2029, was the perfect test subject during its recent close approach.
A test of asteroid
defense systems successfully "rediscovered" the infamous asteroid 99942 Apophis
For this asteroid defense
exercise, all previous data on Apophis were made inaccessibleinfamous asteroid 99942 Apophis
This meant that astronomers
had to start afresh during the asteroid's close approach, which began in December 2020 and culminated in March 2021.
Many asteroid-hunting surveys
, which routinely scan the sky for potentially hazardous asteroids, were involved in the project
During the test, Apophis
was spotted first by the Catalina Sky Survey in Arizona, with subsequent detections from the Asteroid Terrestrial-impact Last Alert System (ATLAS)