Can Is It Really Achieve a Steroid by Crashing Into It? Nobody knows, but we are excited to try

Can Is It Really Achieve a Steroid by Crashing Into It? Nobody knows, but we are excited to try ...

The Double Asteroid Redirection Test (DART) spacecraft was designed to be a one-hit wonder. It will end its days by smashing into an asteroid at 24,000 kilometres per hour on September 26. It was first launched from Earth in November 2021 and was designed to test and demonstrate our ability to defend Earth from a deadly asteroid.

It''s not easy to land a direct hit on an object from 11 million kilometers away. But while this sounds far, NASA has actually selected the asteroid because it is relatively close to Earth. This will provide engineers the possibility to test the spacecraft''s ability to operate itself in the final stages before the impact, as it crashes autonomously.

Dimorphos, a target asteroid measuring 163 metres in length that is surrounded by a 780mm wide asteroid called Didymos. This binary asteroid system was chosen because Dimorphos is in orbit around Didymos, which makes it easier to measure the effects due to the subsequent changes in its orbit. However, the Dimorphos system currently poses no risk to the Earth.

Regardless, NASA is considering only a small planetary defence experiment to alter an asteroid''s path. The technique is kinasizer, which alters the orbit of the asteroid by crashing into it. That''s essentially what''s known as a safety shot in snooker, but played on a planetary level between the spacecraft (as the cue ball) and the asteroid.

A tiny deflection might be sufficient to be certain that this technique can effectively alter the path of an asteroid on a collision path with the Earth.

The DART spacecraft will have a significant impact of around three tonnes of TNT, according to comparisons. The atomic bomb on Hiroshima was equal to 15,000 tonnes of TNT.

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So, with this level devastation and the distance involved, how will we be able to see the crash? Luckily, the DART spacecraft is not traveling alone on its quest, it is carrying a LICIACube, a shoebox-sized mini spacecraft, developed by Argotec. This little companion has recently separated from the DART spacecraft and is now travelling on its own to experience the impact at a safe distance of 55 kilometers.

A cubesat has never been operated around asteroids, thus this allows for new opportunities of exploring space in the near future. Combined, these methods will allow scientists to establish whether the operation has been successful.

It might, however, take weeks for LICIACube to return all images back to Earth. This period will be utterly nerve-wracking, and waiting for good news from a spacecraft is always a difficult time for an engineer.

What happens next? An investigation team will investigate the aftermath of the crash. These scientists will retrace the changes in Dimorphos'' motion around Didymos by observing its orbital period. This is the period during which Dimorphos passes in front and behind Didymos, which will take place every 12 hours.

As this happens, ground telescopes will aim to obtain images of the Dimorphos'' eclipse. DART must create at least a 73-second orbital period change to enable significant deflection.

These measurements will ultimately determine how effective kinetic impact technology is in deflecting a potentially hazardous asteroid we simply don''t know yet.

This is because we know very little about the asteroids'' composition. The enormous uncertainty about how strong Dimorphosis is has made designing a bullet spacecraft a huge engineering challenge. Based on ground observation, the Didymos system is believed to be a rubble-pile composed of many different rocks, but its internal structure is unknown.

There are also significant uncertainties about the effects of the collision. Materials ejected thereafter will contribute to the effects of the crash, providing an additional force. We don''t know if a crater will be formed by the impact or if the asteroid itself will suffer huge deformation, therefore we can''t be sure how much force the collision will unleash.

Future missions Do not end with DART. The European Space Agency is set to launch the Hera mission in 2024, arriving at Didymos in early 2027, in order to take a close look at the other impacts.

By observing the DART effects on Dimorphos, the Hera spacecraft will gain a better understanding of its composition and formation. Defined internal properties of objects such as Didymos and Dimorphos will also aid us in better understanding the danger they may pose to Earth in the event of an impact.

The lessons from this mission will help verify the mechanics of a high-velocity impact. While laboratory experiments and computer models can already validate scientists'' impact predictions, full-scale experiments in space such as DART are the closest we will get to the whole picture. Ultimately, finding out as much as we can about asteroids will help us understand the force we need to confront them in order to deflect them.

The DART mission has prompted worldwide collaboration among scientists in order to address the global issue of planet defense. Together with my colleagues on the DART investigation team, we will investigate the implications of the impact. My own focus will be on the motion of the material that has been ejected from the impact.

The spacecraft impact is scheduled for September 26 at 19:14 Eastern Daylight Time (00:14 British Summer Time on September 27). You may follow the impact on NASA TV.