DART mission: test of asteroid defense – launch of the NASA space probe to deflect the asteroid moon Dimorphos – scinexx.de

On the way to a historical test: This morning the NASA space probe DART took off into space – a probe that is supposed to knock an asteroid out of its orbit for the first time. To do this, the 300-kilogram DART probe will ram the 160-meter-tall Dimorphos chunk in autumn 2022. The reaction of the celestial body provides valuable information for future defense missions in the event of an impending asteroid impact.

Even if our planet has been spared major asteroid impacts in the last millennia, the threat is real. According to NASA estimates, a good 25,000 asteroids with a diameter of more than 140 meters orbit the earth’s orbit regularly. There are also countless other cosmic fragments that are smaller or have not yet been discovered.

Should one of these chunks be on a collision course with the earth, there would be little time to start a defense mission. It is all the more important to test the methods that are suitable for asteroid defense in advance.

This is how the Double Asteroid Redirect Test will work. © NASA/ Johns Hopkins APL

An asteroid is rammed

This is exactly the purpose of the NASA mission DART (Double Asteroid Redirection Test), which is now starting. Your destination is the double asteroid Didymos, which orbits the sun on an elliptical orbit and commutes roughly between the orbits of Earth and Mars. The asteroid duo consists of the 750-meter-tall Didymos and its 160-meter-tall moon Dimorphos – and this is the test object.

The DART space probe, which weighs around 300 kilograms, will initially set course for the twin asteroids after its launch from Vandenberg Space Force Base in California. In just under a year, at the end of September 2022, the defense test will take place: the space probe the size of a drinks machine will rush head-on at Dimorphos at almost 22,000 kilometers per hour. Telescopes all over the world will then observe this experiment, some eleven million kilometers away.

Test for the real thing

“It is the first mission to test whether we can deflect an asteroid through the impact of a space probe,” explains Patrick Michel from the European Space Agency ESA, which supports the DART mission with its own probes on site. The decisive question in the test is whether and how this changes the orbit of the asteroid moon around Didymos – and whether the chunk remains stable despite the impact. If that were not the case, such a diversion could worsen the consequences of an impending impact.

If the asteroid consists of porous material or just loose rubble, then the energy of the kinetic impact is almost completely lost – the defense mission would have failed. It would be even worse if the impact of the probe caused such an unstable asteroid to break apart. Because then, in an emergency, the earth would be threatened with several devastating impacts instead of just one hit.

The double asteroid is well suited as a test object for such a mission because it poses no danger to the earth. In addition, the space probe should only change the orbit of the asteroid moon, which will then remain in orbit around Didymos. Even in the event of an unforeseen change in orbit, this ensures that the asteroid cannot pose a threat to Earth in the distant future either.

What: NASA


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