Tag: dart

NASA’s Hubble Telescope Captures Collision of DART With Asteroid Dimorphos

National Aeronautics and Space Administration’s (NASA’s) Hubble Space Telescope captured a series of photos of asteroid Dimorphos when it was deliberately hit by a 1,200-pound NASA spacecraft called DART on September 26, 2022, according to their statement.

Hubble‘s time-lapse movie of the aftermath of DART’s collision reveals surprising and remarkable, hour-by-hour changes as dust and chunks of debris were flung into space, NASA said in their statement.

Smashing head on into the asteroid at 13,000 miles per hour, the DART impactor blasted over 1,000 tons of dust and rock off of the asteroid.

The Hubble movie offers invaluable new clues into how the debris was dispersed into a complex pattern in the days following the impact, NASA said.

This was over a volume of space much larger than could be recorded by the LICIACube cubesat, which flew past the binary asteroid minutes after DART’s impact, they said.

The primary objective of DART, which stands for Double Asteroid Redirection Test, was to test our ability to alter the asteroid’s trajectory as it orbits its larger companion asteroid, Didymos, the agency said.

Though neither Didymos nor Dimorphos poses any threat to Earth, data from the mission will help inform researchers how to potentially divert an asteroid’s path away from Earth, if ever necessary, the statement said.

The DART experiment also provided fresh insights into planetary collisions that may have been common in the early solar system.

“The DART impact happened in a binary asteroid system. We’ve never witnessed an object collide with an asteroid in a binary asteroid system before in real time, and it’s really surprising.

“I think it’s fantastic. Too much stuff is going on here. It’s going to take some time to figure out,” said Jian-Yang Li of the Planetary Science Institute in Tucson, Arizona.

The study, led by Li along with 63 other DART team members, was published on March 1 in the journal Nature.

The movie shows three overlapping stages of the impact aftermath: the formation of an ejecta cone, the spiral swirl of debris caught up along the asteroid’s orbit about its companion asteroid, and the tail swept behind the asteroid by the pressure of sunlight, resembling a windsock caught in a breeze, the statement said.

The statement described that the Hubble movie starts at 1.3 hours before impact.

In this view both Didymos and Dimorphos are within the central bright spot; even Hubble can’t resolve the two asteroids separately.

The thin, straight spikes projecting away from the center (and seen in later images) are artifacts of Hubble’s optics.

The first post-impact snapshot is 2 hours after the event.

Debris flies away from the asteroid, moving with a range of speeds faster than four miles per hour, fast enough to escape the asteroid’s gravitational pull, so it does not fall back onto the asteroid, the statement said.

The ejecta forms a largely hollow cone with long, stringy filaments.

At about 17 hours after the impact the debris pattern entered a second stage.

The dynamic interaction within the binary system starts to distort the cone shape of the ejecta pattern, the statement described.

The most prominent structures are rotating, pinwheel-shaped features. The pinwheel is tied to the gravitational pull of the companion asteroid, Didymos.

“This is really unique for this particular incident,” said Li. “When I first saw these images, I couldn’t believe these features. I thought maybe the image was smeared or something.” Hubble next captures the debris being swept back into a comet-like tail by the pressure of sunlight on the tiny dust particles, the statement said.

This stretches out into a debris train where the lightest particles travel the fastest and farthest from the asteroid. The mystery is compounded later when Hubble records the tail splitting in two for a few days, the statement said.

A multitude of other telescopes on Earth and in space, including NASA’s James Webb Space Telescope and Lucy spacecraft, also observed the DART impact and its outcomes.

This Hubble movie is part of a suite of new studies published in the journal Nature about the DART mission.

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Can We Really Deflect an Asteroid by Crashing Into It? Nobody Knows, but We Are Excited to Try

NASA’s Double Asteroid Redirection Test (DART) spacecraft is designed to be a one hit wonder. It will end its days by crashing into an asteroid at 24,000 kilometres per hour on September 26. Launched from Earth in November 2021, DART is about the size of a bus and was created to test and prove our ability to defend Earth from a dangerous asteroid.

Landing a direct hit on a target from 11 million kilometres away isn’t easy. But while this sounds far, the asteroid was actually selected by NASA because it is relatively close to Earth. This will give engineers the opportunity to test the spacecraft’s ability to operate itself in the final stages before the impact, as it crashes autonomously.

The target asteroid is called Dimorphos, a body 163 metres in diameter that’s orbiting a 780 metre-wide asteroid called Didymos. This “binary asteroid system” was chosen because Dimorphos is in orbit around Didymos, which makes it easier to measure the result of the impact due to the resulting change in its orbit. However, the Dimorphos system does not currently pose any risk to the Earth.

Regardless, NASA is attempting nothing less than a full scale planetary defence experiment to change an asteroid’s path. The technique being used is called “kinetic impact”, which alters the orbit of the asteroid by crashing into it. That’s essentially what is 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 could be sufficient to prove that this technique can actually change the path of an asteroid on a collision path with the Earth.

But the DART spacecraft is going to be completely blown apart by the collision because it will have an impact equivalent to about three tonnes of TNT. In comparison, the atomic bomb dropped on Hiroshima was equal to 15,000 tonnes of TNT.

So, with this level destruction and the distance involved, how will we be able to see the crash? Luckily, the DART spacecraft is not travelling alone on its quest, it is carrying LICIACube, a shoebox-size mini spacecraft, known as a cubesat, developed by the Italian Space Agency and aerospace engineering company Argotec. This little companion has recently separated from the DART spacecraft and is now travelling on its own to witness the impact at a safe distance of 55km.

Never before has a cubesat operated around asteroids so this provides new potential ways of exploring space in the future. The impact will also be observed from Earth using telescopes. Combined, these methods will enable scientists to confirm whether the operation has been successful.

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

What happens next? An investigation team will look at the aftermath of the crash. These scientists will aim to measure the changes in Dimorphos’ motion around Didymos by observing its orbital period. This is the time during which Dimorphos passes in front and behind Didymos, which will happen every 12 hours.

Ground telescopes will aim to capture images of the Dimorphos’ eclipse as this happens. To cause a significant enough deflection, DART must create at least a 73-second orbital period change after impact – visible as changes in the frequencies of the eclipses.

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 actually know very little of the asteroids’ composition. The great uncertainty around how strong Dimorphosis is has made designing a bullet spacecraft a truly enormous engineering challenge. Based on ground observation, the Didymos system is suspected to be a rubble-pile made up of lots of different rocks, but its internal structure is unknown.

There are also great uncertainties about the outcome of the impact. Material ejected afterwards will contribute to the effects of the crash, providing an additional force. We don’t know whether a crater will be formed by the impact or if the asteroid itself will suffer major deformation, meaning we can’t be sure how much force the collision will unleash.

Future missions Our exploration of the asteroid system does not end with DART. The European Space Agency is set to launch the Hera mission in 2024, arriving at Didymos in early 2027 to take a close look at the remaining impact effects.

By observing the deformations caused by the DART impact on Dimorphos, the Hera spacecraft will gain a better understanding of its composition and formation. Knowledge of the internal properties of objects such as Didymos and Dimorphos will also help us better understand the danger they might pose to Earth in the event of an impact.

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

The DART mission has led to worldwide cooperation among scientists hoping to address the global issue of planetary defence and, together with my colleagues on the DART investigation team, we aim to analyse the impact effects. My own focus will be on studying the motion of the material that is 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 can follow the impact on NASA TV.

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NASA’s DART Asteroid Mission Could Severely Deform Target Asteroid, New Study Reveals

NASA’s Double Asteroid Redirection Test (DART) mission is the world’s first full-scale planetary defence test against potential asteroid impacts on Earth. Researchers now show that instead of leaving behind a relatively small crater, the impact of the DART spacecraft on its target could leave the asteroid near unrecognisable.

A giant asteroid impact on the Earth likely caused the extinction of the dinosaurs, 66 million years ago. Currently no known asteroid poses an immediate threat. But if one day a large asteroid were to be discovered on a collision course with Earth, it might have to be deflected from its trajectory to prevent catastrophic consequences.

Last November, the DART space probe of the US space agency NASA was launched as a first full-scale experiment of such a manoeuvre: Its mission is to collide with an asteroid and to deflect it from its orbit, in order to provide valuable information for the development of such a planetary defense system.

In a new study published in The Planetary Science Journal, researchers of the University of Bern and the National Centre of Competence in Research (NCCR) PlanetS have simulated this impact with a new method. Their results indicate that it may deform its target far more severely than previously thought.

Rubble instead of solid rock

“Contrary to what one might imagine when picturing an asteroid, direct evidence from space missions like the Japanese space agency’s (JAXA) Hayabusa2 probe demonstrate that asteroid can have a very loose internal structure — similar to a pile of rubble — that is held together by gravitational interactions and small cohesive forces,” says study lead-author Sabina Raducan from the Institute of Physics and the National Centre of Competence in Research PlanetS at the University of Bern.

Yet, previous simulations of the DART mission impact mostly assumed a much more solid interior of its asteroid target Dimorphos. “This could drastically change the outcome the collision of DART and Dimorphos, which is scheduled to take place in the coming September,” Raducan points out.

Instead of leaving a relatively small crater on the 160 meter wide asteroid, DART’s impact at a speed of around 24,000kmph could completely deform Dimorphos. The asteroid could also be deflected much more strongly and larger amounts of material could be ejected from the impact than the previous estimates predicted.

A prize winning new approach

“One of the reasons that this scenario of a loose internal structure has so far not been thoroughly studied is that the necessary methods were not available,” study lead-author Sabina Raducan says.

“Such impact conditions cannot be recreated in laboratory experiments and the relatively long and complex process of crater formation following such an impact — a matter of hours in the case of DART — made it impossible to realistically simulate these impact processes up to now,” according to the researcher.

“With our novel modelling approach, which takes into account the propagation of the shock waves, the compaction and the subsequent flow of material, we were for the first time able to model the entire cratering process resulting from impacts on small, asteroids like Dimorphos,” Raducan reports. For this achievement, she was awarded by ESA and by the mayor of Nice at a workshop on the DART follow-up mission HERA.

Widen horizon of expectations

In 2024, the European Space Agency ESA will send a space probe to Dimorphos as part of the space mission HERA. The aim is to visually investigate the aftermath of the DART probe impact. “To get the most out of the HERA mission, we need to have a good understanding of potential outcomes of the DART impact,” says study co-author Martin Jutzi from the Institute of Physics and the National Centre of Competence in Research PlanetS. “Our work on the impact simulations adds an important potential scenario that requires us to widen our expectations in this regard. This is not only relevant in the context of planetary defense, but also adds an important piece to the puzzle of our understanding of asteroids in general,” Jutzi concludes.

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