NASA launches Dart spacecraft with mission to close an asteroid

It may sound like the stuff of science fiction, but DART (the double asteroid redirection test) is a true proof-of-concept experiment, which exploded at 10:21 a.m. Pacific time on Tuesday (0621 GMT Wednesday) on Vandenberg’s SpaceX rocket. Has been doing. Space Force Base in California.

“All systems and weather looking good for tonight’s Falcon 9 launch,” tweeted Elon Musk’s company.

The goal is to slightly change the trajectory of Dimorphos, a “moonlight” approximately 525 feet (160 m, or two Statue of Liberty) wide that encircles a much larger asteroid called Didymos (2,500 feet in diameter). This pair orbits the Sun together.

The impact should occur in the fall of 2022, when the binary asteroid system is 6.8 million miles (11 million kilometers) from Earth, roughly the closest point they meet.

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

To be clear, the asteroids in question pose no threat to our planet.

But they belong to a class of objects known as Near-Earth Objects (NEOs) – asteroids and comets that reach our planet within 30 million miles.

NASA’s Planetary Defense Coordination Office is most interested in masses larger than 460 feet, which have the potential to flatten entire cities or regions with energy many times the energy of an average nuclear bomb.

There are 10,000 known near-Earth asteroids that measure 460 feet or more in size, but none have a significant chance of being hit in the next 100 years. One major caveat: Only 40 percent of those asteroids have been found to date.

– 15,000 mph kicks –

Planetary scientists can create miniature impacts in laboratories and use the results to build sophisticated models of how an asteroid is supposed to turn – but the models always fall short of real-world tests.

Scientists say the Didymos-Dimorphos system is an “ideal natural laboratory” because Earth-based telescopes can easily measure the pair’s brightness variations and judge the time it takes the Moon to orbit its bigger brother .

Since the current orbit period is known, the difference would reveal the effect of an impact occurring between 26 September and 1 October 2022.

Furthermore, since the orbits of asteroids never intersect our planet, they are considered safe to study.

The DART probe, which is a box the size of a large fridge with limousine-sized solar panels on either side, will hit just 15,000 mph in Dimorphos.

Dart probe team chief Andy Rivkin said the current orbital period is 11 hours 55 minutes, and the team expects Kick to be about 10 minutes past that time.

There is some uncertainty about how much energy will be transferred by impact, as the internal structure and porosity of moonshine are not known.

The more debris generated, the more pressure will be exerted on the dimorphos.

“Every time we look at an asteroid, we find stuff we don’t expect,” Rivkin said.

The DART spacecraft also carries sophisticated instruments for navigation and imaging, including the Italian Space Agency’s Light Italian CubeSat for Imaging of Asteroids (LICIACube) to observe the accident and its aftermath.

– nuclear explosion –

The so-called “kinetic impactor” method isn’t the only way to bend an asteroid, but it’s the one most devised with current technology.

Others that have been envisaged include flying a spacecraft closer to provide a smaller gravitational force.

Another is detonating nuclear — but not on the object itself, as in the Armageddon and Deep Impact movies — that would probably create many more dangerous objects.

Scientists estimate that 460-foot asteroids collide once every 20,000 years.

Asteroids six miles or more wide – such as those that struck 66 million years ago and caused the extinction of most life on Earth, including the dinosaurs – occur in about 100-200 million years.

This story has been published without modification in text from a wire agency feed. Only the title has been changed.