NASA’s “Defend the Earth” test vehicle hits an asteroid to change its orbit to avoid a stellar collision | Big Vision

A NASA spacecraft is set to smash into an asteroid on Monday night, ET (Tuesday 27 morning Hong Kong time), slightly altering its orbit. This is NASA’s first “Defense Earth” test, which will help build Earth’s defenses from star strikes in the future.

The NASA mission, called the Double Asteroid Redirection Test (DART), is designed to understand whether the impact of such a human-launched vehicle on an asteroid might help change the orbit of a planet that threatens Earth. “We’re going to move an asteroid and change the motion of a natural object in space, which is unprecedented for mankind,” said Statler, the scientist in charge of the DART mission. The test vehicle for the DART mission is regarding a bus. It was launched in November last year and flew towards the target asteroid. It will fly to the target asteroid on the 26th (Monday), and the estimated impact time is 7:14 pm EST on Monday (7:14 am Hong Kong time on Tuesday 27th) .

The spacecraft was heading towards a double asteroid system, consisting of the larger Didymos and the smaller Dimorphos, which orbited Didymos like the moon. Didymos is regarding 780 meters in diameter, and Dimofas is regarding 160 meters in diameter. Although they are relatively close to the earth at 1.1 million kilometers (near-Earth objects within 48.3 million kilometers from the earth) at the moment of the impact mission, no matter what the impact mission , will not pose a threat to the earth.

The DART mission test is to require the aircraft to hit the smaller Demoface head-on at a speed of 21,600 kilometers per hour. Since the volume of the Demoface is regarding 100 times larger than that of the aircraft, the Demoface will not shatter following being hit. It’s like smashing the Great Pyramid with a golf cart. At most, it hits a pit. The purpose of the mission is to change the speed and operation of Demoface. It is expected to change only 1% of Demoface’s orbital speed following impact, and also slightly change the orbital period. The impact would also tighten the gravitational force between Deimos and Didymus. Scientists say that only a small change in space is enough to deflect an asteroid to pass Earth.

Although there are currently no asteroids coming directly to Earth, there are more than 27,000 near-Earth objects of various shapes and sizes in space. The valuable data collected by this mission can help to construct defense strategies to prevent “comet hitting”, especially to know what force will deflect near-Earth objects that will hit Earth. The European Space Agency (ESA) will launch a spacecraft in 2024 to study the follow-up to NASA’s impact, measuring the physical properties of the two asteroids, impact craters and the orbits of Demoface.

Schematic illustration of NASA’s spacecraft hitting a double asteroid system.