Tue. Dec 7th, 2021

NASA has launched a mission to deliberately hit a spacecraft into an asteroid – a test run humanity would ever need to stop a giant space rock from wiping out life on Earth.

It may sound like science fiction, but the DART – Double Asteroid Redirection Test – is a true proof-of-concept experiment. It exploded Tuesday at 10:21 p.m. (06:21 GMT Wednesday) aboard a SpaceX rocket from Vandenberg Space Force Base in California.

The goal is to slightly change the trajectory of Dimorphos, a “moon” about 160 meters (525 feet) wide, which orbits a much larger asteroid called Didymos 762 meters (2,500 feet) in diameter. The pair orbit the Sun together.

Impact should occur in the third quarter of 2022 when the binary asteroid system is 11 million kilometers (6.8 million miles) from Earth, almost the closest point they ever get.

“What we’re trying to learn is how to ward off a threat,” said Thomas Zuburchen, NASA’s top scientist, about the $ 330 million project, the first of its kind.

To be clear, the asteroids involved poses no threat to the planet. But they belong to a class of bodies known as Near-Earth Objects (NEOs), which approach within 48 million kilometers (30 million miles).

NASA’s Planetary Defense Coordination Office is most interested in those larger than 140 meters (460 feet) in size, which potential to level whole cities or regions with many times the energy of the average nuclear bomb.

There are 10,000 known near-Earth asteroids of as large or larger, but none have a significant chance of hitting within the next 100 years. One big warning: scientists think there are another 15,000 more such objects waiting to be discovered.

Planetary scientist Essam Heggy said that although the NASA mission sounds like science fiction, the threat to the planet is real if the fate of the dinosaurs is recalled 80 million years ago.

“The chance of being hit by an asteroid again is far from science fiction,” he told Al Jazeera. “Asteroids 100 meters and larger are a threat to Earth, and we need to quantify our deflection capability for these threats.”

24,000 km / h kick

Planetary scientists can create miniature impacts in laboratories and use the results to create sophisticated models on how to derive an asteroid – but models are always inferior to actual tests.

Scientists say the Didymos-Dimorphos system is an “ideal natural laboratory” because terrestrial telescopes can easily measure the brightness variation of the pair and judge the time it takes the moon to orbit its big brother.

Since the current orbital period is known, the change will reveal the effect of the collision, which is scheduled to occur between September 26 and October 1, 2022.

What’s more, since the asteroids’ orbit never intersects the Earth, they are thought to be safer to study.

The DART probe, which is a box the size of a large refrigerator with limousine-sized solar panels on either side, will hit Dimorphos at more than 24,000 kilometers per hour (15,000 miles per hour).

Andy Rivkin, the DART investigation team leader, said the current orbital period is 11 hours and 55 minutes, and the team expects the kick to shave 10 minutes from that time.

There is some uncertainty about how much energy will be transferred by the impact because the moon’s internal composition and porosity are not known.

The more debris generated, the more pressure will be put on Dimorphos.

“Every time we arrive at an asteroid, we find things we do not expect,” Rivkin said.

The DART spacecraft also features sophisticated navigation and imaging tools, including the Italian Space Agency’s Light Italian CubeSat for Imaging of Asteroids (LICIACube) to look at the crash and its aftermath.

“We hope the CubeSat will give us the shot – the most spectacular image of DART’s impact and the ejection plume coming from the asteroid. It will be a truly historic, spectacular image, ”said Tom Statler, DART’s program scientist.

Armageddon scenario

The so-called “kinetic impactor” method is not the only way to derive an asteroid, but it is the only technique that is ready to be deployed with current technology.

Others that are supposed to include flying a spacecraft nearby to transmit a small gravitational force.

Yet another explodes a nuclear explosion nearby – but not on the object itself, as in the films Armageddon and Deep Impact – which would probably create many more dangerous objects.

Scientists estimate 140-meter asteroids hit once every 20,000 years.

Asteroids that are 10 km (6 miles) or wider – like the one that hit 66 million years ago and led to the extinction of most life on earth, including the dinosaurs – occur every 100-200 million years.

DART is the latest in several recent NASA missions to explore and interact with asteroids, primordial rock-like remnants of the solar system’s formation 4.6 billion years ago.

Last month, NASA launched a probe into a trip to the Trojan asteroid groups orbiting near Jupiter, while the grab-and-go spacecraft OSIRES-REx is on its way back to Earth with a sample taken last October from the asteroid Bennu was collected.

The spacecraft is on a collision course with an asteroid in the first test of whether the earth can be protected from a potentially catastrophic impact by slightly changing the orbit of a space rock [Bill Ingalls/NASA via AP]

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