Share the QR code < / P > < p > with wechat scanning code to friends and circles of friends < / P > < p > (observer online news) the National Aeronautics and Space Administration (NASA) announced in the early morning of November 24 local time that they launched the first "Planetary Defense tester" with the Falcon 9 carrier rocket of American space technology exploration company (SpaceX). The spacecraft of the "double asteroid redirection test" mission (DART) will actively impact an asteroid to test the technology of deflecting the orbit of Neos through kinetic energy impact < p > the spacecraft is expected to fly for 10 months and hit the target asteroid at the end of September 2022. NASA stressed that the size of the impact target meets the standard of posing a threat to the earth, but the asteroid system involved in the impact mission itself will not pose a threat to the earth < p > NASA twitter screenshot < / P > < p > according to the NASA website, the dart spacecraft, with a total weight of 610kg, will fly to a catamaran asteroid system called Didymos. The system consists of a larger asteroid "Didymos" and a smaller asteroid "dimorphos" running around it. The former is about 780 meters in diameter and the latter is 160 meters in diameter < p > the catamaran asteroid system will reach a position 11 million kilometers away from the earth in late September 2022. According to NASA's plan, this will be the best time to carry out the impact mission. At that time, dart spacecraft will impact the asteroid "dimorphus" with a mass of about 560kg and a speed of 6.8 kilometers per second, trying to change its orbit around "dimorphus" through kinetic energy impact < p > comparison picture of the European Space Agency: the impact target "dimorphus" asteroid has a diameter of 160 meters, which is about the same as that of the Rome arena < / P > < p > the spacecraft also carries a cubic star liciacube provided by the Italian Space Agency. It will be released two days before the impact, responsible for photographing and recording the whole impact process and details, and transmitting the image back to the earth for researchers' analysis < p > NASA predicts that if the impact achieves the expected effect, the current orbital cycle of "dimorphus" orbiting "dimorphus" every 11 hours and 55 minutes will be shortened by 10 minutes < p > demonstration of the impact process released by NASA < / P > < p > dart project scientist Tom Statler said in a statement that astronomers will compare the observation results before and after the impact through astronomical telescopes to determine how much the orbital period of the binary asteroid system has changed, "This key measurement will tell us how the asteroid responded to our deflection test." < / P > < p > in addition, the European Space Agency plans to report to "Didymos" in 2026 The catamaran asteroid system launches new spacecraft to carry out follow-up observation of the impact effect. < / P > < p > the schematic diagram of the impact effect released by the European Space Agency on social media < / P > < p > NASA emphasizes that "dimorphus" is selected As an impact target, because its size meets the criteria of threatening the earth, this catamaran asteroid system itself will not pose a threat to the earth. Since the spacecraft is much smaller than the target, it is impossible for the impact to destroy the asteroid. < / P > < p > American consumer news and business channel (CNBC) The dart mission cost NASA about $330 million and won a $69 million launch contract for SpaceX. This is the first time NASA has tested the "planetary defense mission" At the same time, it is also the first time that SpaceX launches a spacecraft to another celestial body. < / P > < p > the Falcon 9 rocket carrying the dart spacecraft arrived at Vandenberg Air Force base, California, USA before launch. The figure shows that dart is a mission to test the means of "planetary defense", which NASA is trying to study "How to deflect the threat of approaching the earth", but there is little obvious risk of asteroid impact for a long time. "None of the Neos we know today will pose a threat in 100 years." < / P > < p >