It may sound like science fiction, but the Dart (Double Asteroid Redirection Test) is a real experiment.
Broadcast live on NASA television, the Dart spacecraft took off at 10:21 pm this Tuesday (local time) aboard a SpaceX rocket from Vandenberg Space Force Base in California.
What was this mission launched for? To deliberately crash into an asteroid, a trial run in case humanity needs to one day stop a giant space rock from killing life on Earth.
The target is Dimorphos, a “moon” about 160 meters (two statues of freedom) wide, surrounding a much larger asteroid called Didymos (780 meters in diameter). Together, they form a system that orbits the Sun.
“Asteroid Dimorphos, we’re coming for you!” NASA tweeted after launch. He later indicated that the Dart had successfully separated from the second part of the rocket.
“We have received our first signals from #DARTMission, which will continue to deploy its solar panels in the coming hours and prepare for its 10-month round trip to the asteroid,” the space agency added.
The impact should occur in the autumn of 2022, when the pair of rocks meet 11 million kilometers from Earth, the closest point they can get to.
“What we’re trying to learn is how to deflect a threat,” NASA chief scientist Thomas Zuburchen said in a press conference call about the $ 330 million project and the first of its kind.
To make it clear: asteroids pose no threat to our planet. But they belong to a class of bodies known as Near Earth Objects (NEOs): asteroids and comets that come within 50 million kilometers of our planet.
NASA’s Planetary Defense Coordination Office is most interested in bodies that are larger than 140 meters, since they have the potential to devastate cities or entire regions with an energy several times higher than that of normal nuclear bombs.
There are 10,000 known near-Earth asteroids with a size of 140 meters or more, but none have a significant chance of impact in the next 100 years. However, it is estimated that only 40% of these asteroids have been found to date.
Impact at 24,000 km / h
Planetary scientists can create miniature impacts in laboratories and use the results to create sophisticated models on how to deflect an asteroid. But these models are based on flawed assumptions, so they want to run a real-world test.
The Dart probe, a box the volume of a large refrigerator and limousine-sized solar panels on each side, will crash into Dimorphos at just over 15,000 miles per hour, causing a small change in motion. of the asteroid.
Scientists say these rocks are an “ideal natural laboratory” for the test, because Earth-based telescopes can easily measure the variation in brightness of the Didymos-Dimorphos system and calculate the time it takes for Dimorphos to go one full circle around its big brother.
Its orbit never crosses our planet, providing a safe way to measure the effect of impact, which is scheduled to occur between September 26 and October 1, 2022.
Andy Rivkin, head of the Dart research team, said the current orbital period is 11 hours 55 minutes. The team expects the hit to reduce Dimorphos’ orbit by about 10 minutes.
Exists some uncertainty about the amount of energy that will be transferred on impact, since the internal composition and porosity of the small moon is unknown. The more debris generated, the more push Dimorphos will receive.
“Every time we go to an asteroid, we come across things we didn’t expect,” Rivkin said. The Dart spacecraft too contains sophisticated imaging and navigation tools, including the CubeSat of the Italian Space Agency, which will observe the crash and its subsequent effects.
Didymos’s trajectory could also be slightly affected, but it would not significantly alter its course or endanger Earth, according to scientists.