A small asteroid burned over the sky of Ontario, Canada, one week ago. No known damages were caused, as is often the case with such small objects – but the event was a perfect testing ground for NASA’s Scout impact hazard assessment system. Asteroid 2022 WJ1 was discovered on the evening of November 18, and burned through the atmosphere just a few hours later.
Detection and tracking are crucial aspects of planetary defense, and the efforts are focused on dangerous asteroids. However, it is always good to test systems in a real-life scenario. Posing no threat, 2022 WJ1 was just one meter across (three feet). It was observed only 3.5 hours before impact, but NASA was able to track it and predict where it was going to burn.
“The planetary defense community really demonstrated their skill and readiness with their response to this short-warning event,” Kelly Fast, Near-Earth Object Observations program manager for the Planetary Defense Coordination Office (PDCO) at NASA Headquarters in Washington, said in a statement. “Such harmless impacts become spontaneous real-world exercises and give us confidence that NASA’s planetary defense systems are capable of informing the response to the potential for a serious impact by a larger object.”
The NASA-funded Catalina Sky Survey discovered the asteroid. Seven minutes later, Scout knew that there was one chance in four that it would impact somewhere between Mexico and the Atlantic Ocean off the coast of North America.
More observations were soon conducted, including by a group of amateur astronomers in Kansas at Fairpoint Observatory which provided critical observations. A total of 46 observations were conducted.
That data allowed scout to confirm that the small rock was going to hit Earth and from where its bolide was going to be visible with two hours to spare. This allowed researchers around Lake Ontario to prepare for the event and even track small meteorites released as the cosmic body broke apart.
“Small objects such as this one can only be detected when they are very close to Earth, so if they are headed for an impact, time is of the essence to collect as many observations as possible,” said Shantanu Naidu, navigation engineer and Scout operator at JPL. “This object was discovered early enough that the planetary defense community could provide more observations, which Scout then used to confirm the impact and predict where and when the asteroid was going to hit.”
The discovery bodes well for more serious threats. This is only the sixth asteroid that has been tracked in space before hitting Earth.